Bandwidth Aggregation Techniques in Heterogeneous Multi-homed Devices: A Survey
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paper_title: Wake on wireless: an event driven energy saving strategy for battery operated devices

paper_content:

The demand for an all-in-one phone with integrated personal information management and data access capabilities is beginning to accelerate. While personal digital assistants (PDAs) with built-in cellular, WiFi, and Voice-Over-IP technologies have the ability to serve these needs in a single package, the rate at which energy is consumed by PDA-based phones is very high. Thus, these devices can quickly drain their own batteries and become useless to their owner.In this paper, we introduce a technique to increase the battery lifetime of a PDA-based phone by reducing its idle power, the power a device consumes in a "standby" state. To reduce the idle power, we essentially shut down the device and its wireless network card when the device is not being used---the device is powered only when an incoming call is received. Using this technique, we can increase the battery lifetime by up to 115%.In this paper, we describe the design of our "wake-on-wireless" energy-saving strategy and the prototype device we implemented. To evaluate our technique, we compare it with alternative approaches. Our results show that our technique can provide a significant lifetime improvement over other technologies.
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paper_title: Review: Bandwidth aggregation in heterogeneous wireless networks: A survey of current approaches and issues

paper_content:

Future wireless networks are envisaged to consist of a variety of integrated and jointly managed radio access technologies (RATs). This is motivated by the complementary features of the individual RATs. When in the overlapping coverage of the integrated RATs, a multimode terminal can use them simultaneously, thus aggregating bandwidth to enhance performance of high-bandwidth applications. However, there are challenges that must be addressed to achieve efficient bandwidth aggregation. Packet reordering is the most dominant challenge. Packet reordering can lead to excessive delays that can affect real-time applications; it can also affect throughput of TCP applications adversely. To circumvent the reordering problem and other challenges associated with simultaneous use of the terminal's multiple interfaces, bandwidth aggregation solutions are developed. This paper reviews existing bandwidth aggregation solutions in heterogeneous wireless networks. Challenges and several open research issues in the design of bandwidth aggregation approaches are also outlined. To the best of our knowledge, this is the first comprehensive review of existing bandwidth aggregation techniques in heterogeneous wireless networks. This paper, therefore, provides important lessons and information from current bandwidth aggregation solutions, which can be used to guide the development of more efficient bandwidth aggregation approaches.
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paper_title: Routing in multi-radio, multi-hop wireless mesh networks

paper_content:

We present a new metric for routing in multi-radio, multi-hop wireless networks. We focus on wireless networks with stationary nodes, such as community wireless networks.The goal of the metric is to choose a high-throughput path between a source and a destination. Our metric assigns weights to individual links based on the Expected Transmission Time (ETT) of a packet over the link. The ETT is a function of the loss rate and the bandwidth of the link. The individual link weights are combined into a path metric called Weighted Cumulative ETT (WCETT) that explicitly accounts for the interference among links that use the same channel. The WCETT metric is incorporated into a routing protocol that we call Multi-Radio Link-Quality Source Routing.We studied the performance of our metric by implementing it in a wireless testbed consisting of 23 nodes, each equipped with two 802.11 wireless cards. We find that in a multi-radio environment, our metric significantly outperforms previously-proposed routing metrics by making judicious use of the second radio.
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paper_title: Survey of multipath routing protocols for mobile ad hoc networks

paper_content:

This survey investigates multipath routing protocols for mobile ad hoc networks (MANETs). The main objectives of multipath routing protocols are to provide reliable communication and to ensure load balancing as well as to improve quality of service (QoS) of MANETs. These multipath protocols are broadly classified into five categories based on their major goals. The goals are to improve delay, provide reliability, reduce overhead, maximize network life and support hybrid routing. Multipath routing protocols address issues such as multiple paths discovery and maintaining these paths. Issues, objectives, performances, advantages and disadvantages of these protocols are investigated and summarized. A checklist is provided as a guideline so that a network designer can choose an appropriate multipath routing protocol to meet the network's application objectives.
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paper_title: Disk System Architectures for High Performance Computing

paper_content:

Because of the mismatch between I/O and CPU speeds, high-performance computers have long been forced to confront the fundamental I/O bottleneck. As processing power and memory size continue to grow rapidly for micro- and minicomputers, they too will become I/O limited. A number of hardware and software approaches such as parallel read-out disks, expanded storage (for example, solid-state disks), and disk striping, have been used to increase I/O bandwidth and thus narrow the CPU-I/O performance gap. In addition, new developments driven by advances in small-diameter (5.25-in and 3.5-in) disk drives, promise very high I/O bandwidth if large numbers of devices can be organized into arrays of disks. In this paper we review the state of the art in disk devices and I/O controllers, and will describe new approaches for very high-performance I/O based on redundant arrays of inexpensive disks (RAIDs).
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paper_title: E2EMPT: A transport layer architecture for end-to-end multipath transfer

paper_content:

With the evolving of the network technology, the number of terminal equipping with multiple network interfaces keeps increasing because of the deploying of various access methods and the price descending of access devices. However, the terminals can not make full use of multiple interfaces concurrently in conversional network. In this paper, we motivate the advantages of simultaneously using multiple interfaces and present a transport layer architecture, E2EMPT, which supports end-to-end multipath transfer. E2EMPT (i) exploits path diversity and distributes data adaptively following characters of the end-toend paths, (ii) reduces the effect of reordering when transferring on multiple end-to-end paths, (iii) implements smart path management policies to select appropriate end-to-end paths. Our evaluation using simulations suggests that E2EMPT aggregates bandwidth of the terminal interfaces efficiently, and meanwhile improves the security and reliability of data transfer.
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paper_title: G-DBAS: A green and deployable bandwidth aggregation system

paper_content:

The widespread deployment of varying networking technologies, coupled with the exponential increase in end-user data demand, have all led to the proliferation of multi-homed or multi-interface enabled devices. To date, these interfaces are mainly utilized one at a time based on network availability, cost, and user-choice. Researchers have recently focused on leveraging these interfaces simultaneously by proposing solutions to aggregate their bandwidths in order to ultimately increase throughput and satisfy the end-user's growing demand on data. These solutions, however, have faced a steep deployment barrier due to various system design choices and heavy demand on energy. In this paper, we propose a novel Green and Deployable Bandwidth Aggregation System (G-DBAS) for multiple interface enabled devices. G-DBAS addresses a set of challenges including automatically estimating the characteristics of applications and scheduling various connections to different interfaces along with meeting different energy consumption goals set by users. We fully implement G-DBAS on the Windows OS and evaluate various scheduling strategies that we propose. Our implementation and simulation results show that G-DBAS can achieve the user energy-throughput goals while operating as an out-of-the-box standard Windows executable, highlighting its deployability and ease of use.
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paper_title: Using HTTP Pipelining to Improve Progressive Download over Multiple Heterogeneous Interfaces

paper_content:

Today, mobile devices like laptops and cell phones often come equipped with multiple network interfaces, enabling clients to simultaneously connect to independent access networks. Even though applications, such as multimedia streaming and video-on-demand delivery systems, could potentially benefit greatly from the aggregated bandwidth, implementation and standardization challenges have so far hindered the deployment of multilink solutions. Previously, we have explored the benefits of collaboratively using multiple Internet connections to progressively download and play back large multimedia files. In this paper, we present an improved version of our approach that utilizes HTTP's capability of request pipelining in combination with range retrieval requests. While, in our earlier work, the optimal choice of file segmentation size presented a tradeoff between throughput and startup latency, the enhanced solution is able to overcome this tradeoff. The use of very small segments no longer impairs the efficiency of throughput aggregation, which additionally makes our solution robust against link variances and agnostic to network heterogeneity.
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paper_title: Design and implementation of a socket-level bandwidth aggregation mechanism for wireless networks

paper_content:

This paper proposes a mechanism to aggregate bandwidth of multiple network interfaces on a computer. Recently one single computer entails multiple different wireless network interfaces, such as IEEE 802.11a/b/g/n, Bluetooth, WiMAX, and so on. They can be combined, and we can aquire broad bandwidth. We designed and developed a Socket-level Bandwidth Aggregation Mechanism (SBAM). SBAM can aggregate multiple interfaces on a computer to offer broad bandwidth. In addition, implementation in socket layer causes easy deployment and adaptation to existing environment. We evaluated SBAM under actual wireless network environments. SBAM offers broad bandwidth by utilizing various wireless devices on a computer while it avoids modification to existing environment.
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paper_title: Handheld routers: intelligent bandwidth aggregation for mobile collaborative communities

paper_content:

Multi-homed, mobile wireless computing and communication devices can spontaneously form communities to logically combine and share the bandwidth of each other's wide-area communication links using inverse multiplexing. But membership in such a community can be highly dynamic, as devices and their associated WAN links randomly join and leave the community. We identify the issues and tradeoffs faced in designing a decentralized inverse multiplexing system in this challenging setting, and determine precisely how heterogeneous WAN links should be characterized, and when they should be added to, or deleted from, the shared pool. We then propose methods of choosing the appropriate channels on which to assign newly-arriving application flows. Using video traffic as a motivating example, we demonstrate how significant performance gains can be realized by adapting allocation of the shared WAN channels to specific application requirements. Our simulation and experimentation results show that collaborative bandwidth aggregation systems are, indeed, a practical and compelling means of achieving high-speed Internet access for groups of wireless computing devices beyond the reach of public or private access points.
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paper_title: OPERETTA: An optimal energy efficient bandwidth aggregation system

paper_content:

The widespread deployment of varying networking technologies, coupled with the exponential increase in end-user data demand, have led to the proliferation of multi-homed or multi-interface enabled devices. To date, these interfaces are mainly utilized one at a time based on network availability, cost, and user-choice. While researchers have focused on simultaneously leveraging these interfaces by aggregating their bandwidths, these solutions however, have faced a steep deployment barrier. In this paper, we propose a novel optimal, energy-efficient, and deployable bandwidth aggregation system (OPERETTA) for multiple interface enabled devices. OPERETTA satisfies three goals: achieving a user defined throughput level with optimal energy consumption over multiple interfaces, deployability without changes to current legacy servers, and leveraging incremental deployment to achieve increased performance gains. We present the OPERETTA architecture and formulate the optimal scheduling problem as a mixed integer programming problem yielding an efficient solution. We evaluate OPERETTA via implementation on the the Windows OS, and further verify our results with simulations on NS2. Our evaluation shows the tradeoffs between the energy and throughput goals. Furthermore, with no modifications to current legacy servers, OPERETTA achieves throughput gains up to 150% compared to current operating systems with the same energy consumption. In addition, with as few as 25% of the servers becoming OPERETTA enabled, OPERETTA performance reaches the throughput upper bound, highlighting its incremental deployment and performance gains.
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paper_title: A Data-Scheduling Mechanism for Multi-Homed Mobile Terminals with Disparate Link Latencies

paper_content:

A mobile terminal equipped with multiple network interfaces can often be found under coverage of multiple access networks. Multihoming enables mobile terminals to communicate simultaneously through multiple interfaces. Connection-oriented transport layer mechanisms ensure reliable, in-order delivery of data, however parallel data transfers in multihoming face problems due to out-of-order reception of data which causes fast-retransmissions and limit the communication throughput. In this paper, we propose a transport layer based mechanism which stripes one flow''s data across multiple disjoint paths efficiently, reducing possible occurrence of out-of-order data. Our mechanism estimates arrival times of data packets to be sent through available paths in an association, and decides which packets are to be sent through each path. We compared our mechanism with a relatively closer approach called Westwood SCTP. We illustrate with the help of simulation results that our mechanism proves to improve multipath communication.
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paper_title: Architecture, Implementation, and Evaluation of a Concurrent Multi-path Real-time Transport Control Protocol

paper_content:

Current multimedia applications utilize a combination of real-time transport protocol (RTP) and user datagram protocol (UDP) for transmitting real-time streams across the network. Bandwidth aggregation over multiple paths for improved real-time stream transmission can be achieved using either a combination of multi-flow RTP (MRTP) and UDP, or various adaptations of Partial reliability (PR) extension of SCTP (SCTP-PR). However, they are not really useful for balancing load on the multiple paths. The receiving end of these protocols can neither identify late arriving packets nor notify the sender about them. The novel concurrent multi-path real-time transmission control protocol (cmpRTCP) proposed, implemented, and evaluated in this work not only overcomes the problems faced by existing multi-path protocols, but also preserves the novel design and implementation features of the recently proposed cmpTCP. This protocol which has a congestion controller and a packet scheduler embedded in its core, intelligently exploits the availability of multiple paths between multi-homed hosts for concurrent transmission and showcases the ability of (i) remaining TCP-friendly while aggregating bandwidth, (ii) balancing load across paths by scheduling more packets on less congested paths, (iii) increasing end-to-end connection reliability by using multiple paths and (iv) improving QoS at the receiving end by scheduling more packets on better paths.
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paper_title: Deployable multipath communication scheme with sufficient performance data distribution method

paper_content:

Multi-homed environments are increasingly common, especially for mobile users. And several multipath communication techniques have been proposed, such as multipath TCP communication techniques. Multipath TCP techniques have potential to fully utilize multiple paths, but, these methods have difficulties in implementation and deployment, because users need to modify their applications or operating system or both. In this paper, we propose simple multipath communication technique, which we call Arrival-Time matching Load-Balancing (ATLB). ATLB is designed to be easily implementable on several environments. Besides, we also introduce overlay network approach which implicitly provides parallel data transfer scheme to users. The ATLB continuously calculates transmission delays of each path, including TCP queuing delay at a sender and network delay, and then sends a data segment through the TCP connection with the lowest delay. Simulation results show that ATLB realizes sufficient performance even in heterogeneous environments where the quality of paths differs. Measurement results over our wireless LAN test-bed system suggest that ATLB can fully utilize the aggregate available bandwidth over unstable multiple wireless links.
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paper_title: The Design of Mobile Concurrent Multipath Transfer in Multihomed Wireless Mobile Networks

paper_content:

As more and more devices are equipped with multiple network interfaces, the multihomed technology is becoming an important technology that can provide more reliable connection against the network failure and higher data transmission rate. Concurrent Multipath Transfer (CMT), which is based on SCTP, is devised for multihomed networks. CMT can transmit data over all paths to maximize the data transmission speed. One of the main concerns of CMT is the receiver buffer blocking issue, especially in multihomed wireless mobile networks. Receiver buffer blocking is mainly caused by lost data. In this paper, we propose mobile CMT (mCMT) over wireless networks to deal with the receiver buffer blocking caused by error loss and handoff loss. mCMT has the features of (i) path-oriented multistreaming, (ii) MIH-assisted handoff mechanism, in which MIH denotes Media Independent Handover and (iii) association resume. Path-oriented multistreaming can reduce the receiver buffer blocking caused by error loss. MIH-assisted a handoff can reduce the amount of packet loss during a handoff, which may lead to receiver buffer blocking. Moreover, mCMT introduces the concept of association resume to recover the disconnected association. Simulation results show that mCMT can reduce the effect of the receiver buffer blocking effectively for devices that have smaller buffer size.
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paper_title: DNIS: a middleware for dynamic multiple network interfaces scheduling

paper_content:

Wireless Intelligent Networks Center, Nile University, Smart Village, Egypt Many of today's mobile devices are equipped with multiple network interfaces that can be used to connect to the Internet, including Ethernet, WiFi, 3G, and Bluetooth. However, current operating systems, such as Windows and Linux, typically choose only one of the available network interfaces and assign all the traffic to it, even if more than one is connected to the Internet. This results in an obvious under utilization of the available bandwidth. Different bandwidth aggregation techniques suggested altering different layers of the TCP/IP stack which requires applying modifications on the client's stack and/or the cloud, which cannot be widely deployed easily. In this work, we present DNIS, a networking middleware that achieves bandwidth aggregation using per-TCP connection scheduling on different interfaces in a way that is transparent to both the user and the applications. DNIS is composed of two main components: (1) a parameter estimator that estimates the applications' characteristics and requirements as well as interfaces' properties; (2) a scheduler that uses the estimated parameters to assign different TCP connections to network interfaces. We present an implementation for DNIS for the Windows OS and show its performance for different scheduling algorithms. Our initial results show significant enhancement of the overall device's throughput, up to 54%, increasing resource utilization and enhancing the user's experience.
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paper_title: DBAS: A Deployable Bandwidth Aggregation System

paper_content:

The explosive increase in data demand coupled with the rapid deployment of various wireless access technologies have led to the increase of number of multi-homed or multi-interface enabled devices. Fully exploiting these interfaces has motivated researchers to propose numerous solutions that aggregate their available bandwidths to increase overall throughput and satisfy the end-user's growing data demand. These solutions, however, have faced a steep deployment barrier that we attempt to overcome in this paper. We propose a Deployable Bandwidth Aggregation System (DBAS) for multi- interface enabled devices. Our system does not introduce any intermediate hardware, modify current operating systems, modify socket implementations, nor require changes to current applications or legacy servers. The DBAS architecture is designed to automatically estimate the characteristics of applications and dynamically schedule various connections or packets to different interfaces. Since our main focus is deployability, we fully implement DBAS on the Windows operating system and evaluate various modes of operation. Our implementation and simulation results show that DBAS achieves up to more than double the throughput gains compared to current operating systems, while operating as an out-of-the- box standard Windows executable, highlighting its deployability.
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paper_title: Collaborative Downloading for Multi-homed Wireless Devices

paper_content:

Mobile devices are increasingly equipped with multiple network interfaces: Wireless Local Area Network (WLAN) interfaces for local connectivity and Wireless Wide Area Network (WWAN) interfaces for wide-area connectivity. The WWAN typically provides much wider coverage but much lower speeds than the WLAN. To address this dichotomy, we consider collaborative downloading among mobile devices in close proximity. We demonstrate the potential benefits of such an approach and discuss the many challenges to realizing it in practice: incentivizing cooperation by adequately compensating nodes, effecting such cooperation via an efficient protocol, and facilitating it with a suitable user interface. We present our current thinking on these as we design a collaborative downloading system called COMBINE.
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paper_title: cmpSCTP: An Extension of SCTP to Support Concurrent Multi-Path Transfer

paper_content:

This paper introduced cmpSCTP, a transport layer solution for concurrent multi-path transfer that modifies the standard Stream Control Transmission Protocol (SCTP). The cmpSCTP aims at exploiting SCTP's multi-homing capability by selecting several best paths among multiple available network interfaces to improve data transfer rate to the same multi-homed device. Through the use of path monitoring and packet allotment techniques, cmpSCTP tries to transmit given amount of packets at corresponding path as its ability. At the same time, cmpSCTP updates the transmission strategy based on the real-time information of all of paths. Using cmpSCTP's flexible path management capability, we may switch the flow between multiple paths automatically to realize seamless path handover. Extensive simulations under different scenarios using OPNET verified that cmpSCTP can effectively enhance transmission efficiency and highlighted the superiority of cmpSCTP against the other SCTP's extension implementations under performance indexes such as throughput, handover latency, packet delay, and packet loss.
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paper_title: A Concurrent Multipath TCP and Its Markov Model

paper_content:

Concurrent Multipath Transport (CMT) has been of increasing interest recently for aggregating bandwidth, balancing load, and increasing reliability. In this paper we propose a concurrent multipath Transport Control Protocol (cmpTCP), which is an extension of TCP New Reno and Steam Control Transmission Protocol (SCTP). The proposed cmpTCP has been implemented by altering and extending library-based open-source for SCTP. The proposed cmpTCP manages transport control parameters of all paths simultaneously; a scheduler concurrently dispatches packets over all the paths from a common transmission queue. However, one virtual retransmission queue is maintained for each path, and the receiver sends acknowledgment for a packet on the same path on which the packet is received. A Markov model for estimation of expected window size of each path has been proposed. Next, the proposed model has been utilized to derive an expression for computing average data transmission rate when the proposed cmpTCP is used. To validate performance of the proposed model, two host computers were connected through two independent network emulators. Each network emulator runs on a separate computer, and the network parameters are adjusted independently. We used our cmpTCP for transferring files from one host to the other. Comparison of experimental results with model predicted results shows excellent agreement.
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paper_title: WiMP-SCTP: Multi-Path Transmission Using Stream Control Transmission Protocol (SCTP) in Wireless Networks

paper_content:

In this paper, WiMP-SCTP, which allows a host to improve its transmission goodput in wireless networks using multi-path transmission of stream control transmission protocol, is proposed. Along with a transmission mode switching scheme, two transmission modes of WiMP-SCTP, i.e., the "Data-duplicating Mode" and the "Data-striping Mode", are designed to enhance transmission goodputs for different wireless link status. The issue of path selection scenarios are investigated and the possible solution for the path selection is also discussed in this paper.
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paper_title: Multi-Path Load Balancing in Transport Layer

paper_content:

In this paper, we propose an extension to current TCP protocol named concurrent TCP (cTCP), which can improve throughput of connections through balancing traffic load on multiple end-to-end paths. We keep the single-sliding-window architecture of TCP untouched for compatibility reasons. The two core components of the design are a packet scheduling switch that balances load among paths, and a duplicated acknowledgement classifier that handles packet reordering. We implemented our protocol in FreeBSD kernel and compared the performance of cTCP with theoretical results. Experiment outcomes show that throughputs of our protocol are close to the ideal values.
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paper_title: Improving throughput and reliability in mobile wireless networks via transport layer bandwidth aggregation

paper_content:

Currently, most battlefield mobile communication devices are equipped with multiple wireless interfaces. The main target of the multiple interfaces is to increase the communication reliability between the soldiers in the battlefield and the command center, so that if one of the interfaces fails, the other interfaces can still provide a communication path. In this case each application data stream is limited to use only one communication channel. Due to the limited and variable bandwidth of the wireless channels, as well as their lossy and break-prone nature, the performance of mobile applications can be greatly hurt. In this paper, we present a transport layer solution for aggregating the bandwidth of the available interfaces. Our solution is based on extending Stream Control Transmission Protocol (SCTP). Our choice to extend SCTP for bandwidth aggregation was motivated by its inherent support for multi-homing. The extended SCTP, which we refer to as Load Sharing-SCTP (LS-SCTP), is able to aggregate the bandwidth of all the active transmission paths between the communicating endpoints. In addition, LS-SCTP dynamically adds/drops communication paths to the aggregated paths bundle. To ensure that the aggregate connection will not stall due to the high loss rate or continuous failure of individual paths, LS-SCTP includes path monitoring and packet assignment mechanisms that distribute the packets on the paths according to their current condition. Simulation results demonstrate the effectiveness of our proposed mechanism in providing throughput and reliability to mobile applications under battlefield conditions.
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paper_title: G-DBAS: A green and deployable bandwidth aggregation system

paper_content:

The widespread deployment of varying networking technologies, coupled with the exponential increase in end-user data demand, have all led to the proliferation of multi-homed or multi-interface enabled devices. To date, these interfaces are mainly utilized one at a time based on network availability, cost, and user-choice. Researchers have recently focused on leveraging these interfaces simultaneously by proposing solutions to aggregate their bandwidths in order to ultimately increase throughput and satisfy the end-user's growing demand on data. These solutions, however, have faced a steep deployment barrier due to various system design choices and heavy demand on energy. In this paper, we propose a novel Green and Deployable Bandwidth Aggregation System (G-DBAS) for multiple interface enabled devices. G-DBAS addresses a set of challenges including automatically estimating the characteristics of applications and scheduling various connections to different interfaces along with meeting different energy consumption goals set by users. We fully implement G-DBAS on the Windows OS and evaluate various scheduling strategies that we propose. Our implementation and simulation results show that G-DBAS can achieve the user energy-throughput goals while operating as an out-of-the-box standard Windows executable, highlighting its deployability and ease of use.
---
paper_title: Design and implementation of a socket-level bandwidth aggregation mechanism for wireless networks

paper_content:

This paper proposes a mechanism to aggregate bandwidth of multiple network interfaces on a computer. Recently one single computer entails multiple different wireless network interfaces, such as IEEE 802.11a/b/g/n, Bluetooth, WiMAX, and so on. They can be combined, and we can aquire broad bandwidth. We designed and developed a Socket-level Bandwidth Aggregation Mechanism (SBAM). SBAM can aggregate multiple interfaces on a computer to offer broad bandwidth. In addition, implementation in socket layer causes easy deployment and adaptation to existing environment. We evaluated SBAM under actual wireless network environments. SBAM offers broad bandwidth by utilizing various wireless devices on a computer while it avoids modification to existing environment.
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paper_title: Enhancing Video-on-Demand Playout over Multiple Heterogeneous Access Networks

paper_content:

Multimedia streaming is increasing in popularity and has become one of the dominating services on the Internet today. Even though user devices are often equipped with multiple network interfaces and in reach of several access networks at the same time, media streams are normally communicated over only one of the available Internet connections. ::: ::: In this paper, we explore the challenges and potential benefits of using multiple access networks simultaneously. Exploiting HTTP's capability of handling requests for specific byte ranges of a file, we present the implementation of a lightweight, application-layer, on-demand streaming service that requires no changes to existing servers and infrastructure. ::: ::: Based on real-world experiments with a multihomed host, we investigate the potential performance gains of video-on-demand playout. We achieve a bandwidth aggregation efficiency of 90% when downloading over 3 heterogeneous access networks in parallel. In addition, we analyze the effect of file segmentation on the buffer requirements and the startup latency.
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paper_title: Handheld routers: intelligent bandwidth aggregation for mobile collaborative communities

paper_content:

Multi-homed, mobile wireless computing and communication devices can spontaneously form communities to logically combine and share the bandwidth of each other's wide-area communication links using inverse multiplexing. But membership in such a community can be highly dynamic, as devices and their associated WAN links randomly join and leave the community. We identify the issues and tradeoffs faced in designing a decentralized inverse multiplexing system in this challenging setting, and determine precisely how heterogeneous WAN links should be characterized, and when they should be added to, or deleted from, the shared pool. We then propose methods of choosing the appropriate channels on which to assign newly-arriving application flows. Using video traffic as a motivating example, we demonstrate how significant performance gains can be realized by adapting allocation of the shared WAN channels to specific application requirements. Our simulation and experimentation results show that collaborative bandwidth aggregation systems are, indeed, a practical and compelling means of achieving high-speed Internet access for groups of wireless computing devices beyond the reach of public or private access points.
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paper_title: MOTA: engineering an operator agnostic mobile service

paper_content:

There are two emerging trends in the mobile data world. First, mobile data is exploding at a rapid rate with analysts predicting 25-50X growth by the year 2015. The second trend is that users are demanding greater degree of flexibility in selecting their operators at fine timescales. Across Asia, dual-SIM phones have become popular, while Apple is rumored to be designing a Universal SIM that will allow iPhone users to toggle between different operators. This latter trend points towards an impending disruption in wireless service models which could also be the need of the hour from the spectrum shortage perspective. This points towards a new service model where users can choose an operator based on application needs. However, if users make this choice greedily without network assistance, it can exacerbate spectrum scarcity and degrade user experience. In this work, we consider user devices with multiple network interfaces (3G, LTE etc.) that can be simultaneously active and each running multiple applications. We propose the MOTA service model to enable users to associate each interface with the operator of choice at fine time scales. Under the MOTA service model, through concise signalling information, operators provide information about their own network, so that each user can (i) choose a suitable operator for each interface, and (ii) choose an interface for each active application. We make the following contributions in this paper. First, we propose concise network signalling that assists users to make informed choices even under mobility. Second, we develop user-choice algorithms that maximize a suitable notion of user satisfaction while using spectrum resources efficiently. Third, we perform extensive evaluation over actual base station deployment in a city coupled with real signal propagation maps. Our results with two operators show that, MOTA service model provides capacity gain in the range 2.5-4X over the current existing service model. Finally, we argue that our solution is practically implementable by combining appropriate IEEE standards and IETF proposals.
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paper_title: Transport level mechanisms for bandwidth aggregation on mobile hosts

paper_content:

Present mobile computing does not support the simultaneous use of multiple heterogeneous network interfaces for a single transport layer connection. We describe a solution for channel aggregation at the transport layer, which provides increased bandwidth to mobile nodes. We present R-MTP (reliable multiplexing transport protocol), a rate-based reliable transport protocol capable of multiplexing data from a single application data stream across multiple network interfaces. Due to the lossy nature of wireless links in mobile environments, R-MTP tracks packet interarrival time for discrimination between congestion-based and transmission-based losses as well as better bandwidth estimation. The challenges to such a reliable protocol lie in the coordination of packets across streams with varying channel characteristics. Our experimental results validate R-MTP's bandwidth estimation and loss characterization techniques. Successful bandwidth aggregation is demonstrated in ideal and lossy environments.
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paper_title: OPERETTA: An optimal energy efficient bandwidth aggregation system

paper_content:

The widespread deployment of varying networking technologies, coupled with the exponential increase in end-user data demand, have led to the proliferation of multi-homed or multi-interface enabled devices. To date, these interfaces are mainly utilized one at a time based on network availability, cost, and user-choice. While researchers have focused on simultaneously leveraging these interfaces by aggregating their bandwidths, these solutions however, have faced a steep deployment barrier. In this paper, we propose a novel optimal, energy-efficient, and deployable bandwidth aggregation system (OPERETTA) for multiple interface enabled devices. OPERETTA satisfies three goals: achieving a user defined throughput level with optimal energy consumption over multiple interfaces, deployability without changes to current legacy servers, and leveraging incremental deployment to achieve increased performance gains. We present the OPERETTA architecture and formulate the optimal scheduling problem as a mixed integer programming problem yielding an efficient solution. We evaluate OPERETTA via implementation on the the Windows OS, and further verify our results with simulations on NS2. Our evaluation shows the tradeoffs between the energy and throughput goals. Furthermore, with no modifications to current legacy servers, OPERETTA achieves throughput gains up to 150% compared to current operating systems with the same energy consumption. In addition, with as few as 25% of the servers becoming OPERETTA enabled, OPERETTA performance reaches the throughput upper bound, highlighting its incremental deployment and performance gains.
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paper_title: The PPP Multilink Protocol (MP)

paper_content:

This document proposes a method for splitting, recombining and sequencing datagrams across multiple logical data links. This work was originally motivated by the desire to exploit multiple bearer channels in ISDN, but is equally applicable to any situation in which multiple PPP links connect two systems, including async links. This is accomplished by means of new PPP [2] options and protocols.
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paper_title: DNIS: a middleware for dynamic multiple network interfaces scheduling

paper_content:

Wireless Intelligent Networks Center, Nile University, Smart Village, Egypt Many of today's mobile devices are equipped with multiple network interfaces that can be used to connect to the Internet, including Ethernet, WiFi, 3G, and Bluetooth. However, current operating systems, such as Windows and Linux, typically choose only one of the available network interfaces and assign all the traffic to it, even if more than one is connected to the Internet. This results in an obvious under utilization of the available bandwidth. Different bandwidth aggregation techniques suggested altering different layers of the TCP/IP stack which requires applying modifications on the client's stack and/or the cloud, which cannot be widely deployed easily. In this work, we present DNIS, a networking middleware that achieves bandwidth aggregation using per-TCP connection scheduling on different interfaces in a way that is transparent to both the user and the applications. DNIS is composed of two main components: (1) a parameter estimator that estimates the applications' characteristics and requirements as well as interfaces' properties; (2) a scheduler that uses the estimated parameters to assign different TCP connections to network interfaces. We present an implementation for DNIS for the Windows OS and show its performance for different scheduling algorithms. Our initial results show significant enhancement of the overall device's throughput, up to 54%, increasing resource utilization and enhancing the user's experience.
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paper_title: A User-level Socket Layer over Multiple Physical Network Interfaces

paper_content:

In this paper, we describe the design and implementation of an UDP-based socket that utilizes multiple network interface units connected through one or more networks. The socket is a middleware layer that provides abstract network APIs to hide low-level technical details from users. Parallel message fragmentation and reconstruction techniques and a reliable UDP-based protocol are introduced. The proposed socket layer transparently provides an expandable high bandwidth solution, fault tolerance, and load balancing for transmitting large messages over multiple networks. A prototype socket based on this model, called MuniSocket (Multiple Network Interface Socket), has been implemented and evaluated.
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paper_title: DBAS: A Deployable Bandwidth Aggregation System

paper_content:

The explosive increase in data demand coupled with the rapid deployment of various wireless access technologies have led to the increase of number of multi-homed or multi-interface enabled devices. Fully exploiting these interfaces has motivated researchers to propose numerous solutions that aggregate their available bandwidths to increase overall throughput and satisfy the end-user's growing data demand. These solutions, however, have faced a steep deployment barrier that we attempt to overcome in this paper. We propose a Deployable Bandwidth Aggregation System (DBAS) for multi- interface enabled devices. Our system does not introduce any intermediate hardware, modify current operating systems, modify socket implementations, nor require changes to current applications or legacy servers. The DBAS architecture is designed to automatically estimate the characteristics of applications and dynamically schedule various connections or packets to different interfaces. Since our main focus is deployability, we fully implement DBAS on the Windows operating system and evaluate various modes of operation. Our implementation and simulation results show that DBAS achieves up to more than double the throughput gains compared to current operating systems, while operating as an out-of-the- box standard Windows executable, highlighting its deployability.
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paper_title: GreenBag: Energy-Efficient Bandwidth Aggregation for Real-Time Streaming in Heterogeneous Mobile Wireless Networks

paper_content:

Modern mobile devices are equipped with multiple network interfaces, including 3G/LTE and WiFi. Bandwidth aggregation over LTE and WiFi links offers an attractive opportunity of supporting bandwidth-intensive services, such as high-quality video streaming, on mobile devices. However, achieving effective bandwidth aggregation in mobile environments raises several challenges related to deployment, link heterogeneity, network fluctuation, and energy consumption. We present GreenBag, an energy-efficient bandwidth aggregation middleware that supports real-time data-streaming services over asymmetric wireless links, requiring no modifications to the existing Internet infrastructure and servers. GreenBag employs several techniques, including medium load balancing, efficient segment management, and energy-aware mode control, to resolve such challenges. We implement a prototype of GreenBag on Android-based mobile devices which hosts, to the best knowledge of the authors, the first LTE-enabled bandwidth aggregation prototype for energy-efficient real-time video streaming. Our experiment results in both emulated and real-world environments show that GreenBag not only achieves good bandwidth aggregation to provide QoS in bandwidth-scarce environments but also efficiently saves energy on mobile devices. Moreover, energy-aware GreenBag can minimize video interruption while consuming 14-25% less energy than the non-energy-aware counterpart in real-world experiments.
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paper_title: A Transport Layer Approach for Improving End-to-End Performance and Robustness Using Redundant Paths

paper_content:

Recent work on Internet measurement and overlay networks has shown that redundant paths are common between pairs of hosts and that one can often achieve better end-to-end performance by adaptively choosing an alternate path [8, 28]. In this paper, we propose an end-to-end transport layer protocol, mTCP, which can aggregate the available bandwidth of those redundant paths in parallel. By striping one flow's packets across multiple paths, mTCP can not only obtain higher end-to-end throughput but also become more robust under path failures. When some paths fail, mTCP can continue sending packets on other living paths and the recovery process normally takes only a few seconds. Because mTCP could obtain an unfair share of bandwidth under shared congestion, we integrate a shared congestion detection mechanism into our system. It allows us to dynamically detect and suppress paths with shared congestion so as to alleviate the aggressiveness problem. mTCP can also passively monitor the performance of several paths in parallel and discover better paths than the path provided by the underlying routing infrastructure. We also propose a heuristic to find disjoint paths between pairs of nodes using traceroute. We have implemented our system on top of overlay networks and evaluated it in both Planet-Lab and Emulab.
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paper_title: Improved data distribution for multipath TCP communication

paper_content:

Multi-homed environments are increasingly common, especially for mobile users. To efficiently utilize multiple access lines for single file transfer, multipath TCP communication methods have been proposed. A multipath TCP enables simultaneous distributed data transfer between two end-points on multiple TCP connections. However, these methods cannot fully utilize the available bandwidth of multiple paths because they do not properly consider the end-to-end delay of packet transmission, so out-of-order data arrival at a receiver causes a bottleneck in data sort operations. This problem is more severe in environments where the quality of each path is different or unstable, such as in wireless environments. To solve this problem, we propose a multipath TCP communication method that includes a data distribution method to enable in-order delivery at a receiver. We call this arrival-time matching load-balancing (ATLB). ATLB continuously calculates the delay of each path, including the TCP queuing delay at a sender and the network delay, and then sends a data segment through the TCP connection with the lowest end-to-end delay. Simulation results show that ATLB improves end-to-end throughput, especially in heterogeneous environments where the quality of paths differs. For example, ATLB enabled twice the throughput with the conventional multipath TCP. We also report performance evaluation results from our ATLB test bed system in a wireless network environment. Our ATLB test bed system was able to fully utilize the aggregate available bandwidth of unstable multiple wireless links.
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paper_title: Aggregating Bandwidth for Multihomed Mobile Collaborative Communities

paper_content:

Multihomed, mobile wireless computing and communication devices can spontaneously form communities to logically combine and share the bandwidth of each other's wide-area communication links using inverse multiplexing. But, membership in such a community can be highly dynamic, as devices and their associated WWAN links randomly join and leave the community. We identify the issues and trade-offs faced in designing a decentralized inverse multiplexing system in this challenging setting and determine precisely how heterogeneous WWAN links should be characterized and when they should be added to, or deleted from, the shared pool. We then propose methods of choosing the appropriate channels on which to assign newly arriving application flows. Using video traffic as a motivating example, we demonstrate how significant performance gains can be realized by adapting allocation of the shared WWAN channels to specific application requirements. Our simulation and experimentation results show that collaborative bandwidth aggregation systems are, indeed, a practical and compelling means of achieving high-speed Internet access for groups of wireless computing devices beyond the reach of public or private access points
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paper_title: Using bandwidth aggregation to improve the performance of quality-adaptive streaming

paper_content:

Devices capable of connecting to multiple, overlapping networks simultaneously is becoming increasingly common. For example, most laptops are equipped with LAN- and WLAN-interface, and smart phones can typically connect to both WLANs and 3G mobile networks. At the same time, streaming high-quality video is becoming increasingly popular. However, due to bandwidth limitations or the unreliable and unpredictable nature of some types of networks, streaming video can be subject to frequent periods of rebuffering and characterized by a low picture quality. In this paper, we present a multilink extension to the data retrieval part of the DAVVI adaptive, segmented video streaming system. DAVVI implements the same core functionality as the MPEG DASH standard. It uses HTTP to retrieve data, segments video, provides clients with a description of the content, and allows clients to switch quality during playback. Any DAVVI-data retrieval extensions can also be implemented in a DASH-solution. The multilink-enabled DAVVI client divides video segments into smaller subsegments, which are requested over multiple interfaces simultaneously. The size of each subsegment is dynamic and calculated on the fly, based on the throughput of the different links. This is an improvement over our earlier subsegment approach, which divided segments into fixed size subsegments. The quality of the video is adapted based on the measured, aggregated throughput. Both the static and the dynamic subsegment approaches were evaluated with on-demand streaming and quasi-live streaming. The new subsegment approach reduces the number of playback interruptions and improves video quality significantly for all cases where the earlier approach struggled. Otherwise, they show similar performance.
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paper_title: Intentional networking: opportunistic exploitation of mobile network diversity

paper_content:

Mobile devices face a diverse and dynamic set of networking options. Using those options to the fullest requires knowledge of application intent. This paper describes Intentional Networking, a simple but powerful mechanism for handling network diversity. Applications supply a declarative label for network transmissions, and the system matches transmissions to the most appropriate network. The system may also defer and re-order opportunistic transmissions subject to application-supplied mutual exclusion and ordering constraints. We have modified three applications to use Intentional Networking: BlueFS, a distributed file system for pervasive computing, Mozilla's Thunderbird e-mail client, and a vehicular participatory sensing application. We evaluated the performance of these applications using measurements obtained by driving a vehicle through WiFi and cellular 3G network coverage. Compared to an idealized solution that makes optimal use of all aggregated available networks but that lacks knowledge of application intent, Intentional Networking improves the latency of interactive messages from 48% to 13x, while adding no more than 7% throughput overhead.
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paper_title: LS-SCTP: a bandwidth aggregation technique for stream control transmission protocol

paper_content:

Stream Control Transmission Protocol (SCTP) specifications utilize the multiple paths capabilities between the sender and receiver for retransmission of lost data chunks and as a backup in case of primary path failure. Under normal conditions, all data chunks are sent on the primary path chosen by the SCTP user during the transport connection initiation. In this paper, we address in detail various aspects related to extending and engineering SCTP in order to utilize the available paths for simultaneous transmission of data chunks, while maintaining the SCTP congestion control on each path so as to ensure fair integration with other traffic in the network. The extended SCTP, referred to as Load-Sharing SCTP (LS-SCTP), is able to aggregate the bandwidth of all the active transmission paths between the communicating endpoints. LS-SCTP monitors the paths, and accordingly it chooses the paths that are suitable for load sharing. LS-SCTP retransmission mechanism accelerates the delivery of missing data to the receiver in order to prevent stalling the transport connection while waiting for missing data chunks. Simulation results show that LS-SCTP is extremely beneficial for networks with limited bandwidth, high loss rate and failure prone links.
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paper_title: Using multiple links to increase the performance of bandwidth-intensive UDP-based applications

paper_content:

Networked devices often come equipped with multiple network interfaces, and bandwidth aggregation is one of the many possible benefits of using multiple interfaces simultaneously. Real-world networks introduce several challenges that have often been ignored by related work on bandwidth aggregation. The challenges include limited connectivity due to NAT-boxes, link heterogeneity and link variability. In this paper, we present a transparent solution for proxy-based bandwidth aggregation that is able to overcome the different deployment and link heterogeneity challenges present in real-world networks. Our focus has been on increasing the performance of bandwidth-intensive UDP-based applications, and through evaluation we show that our solution efficiently aggregates bandwidth and increases the in-order throughput. Previously, we introduced a multi-link UDP proxy solution that improves in-order throughput. This paper presents a significant extension and improvement in terms of support for middle-boxes (NAT), congestion control, a client-based resequencer and support for all operating systems.
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paper_title: Collaborative Downloading for Multi-homed Wireless Devices

paper_content:

Mobile devices are increasingly equipped with multiple network interfaces: Wireless Local Area Network (WLAN) interfaces for local connectivity and Wireless Wide Area Network (WWAN) interfaces for wide-area connectivity. The WWAN typically provides much wider coverage but much lower speeds than the WLAN. To address this dichotomy, we consider collaborative downloading among mobile devices in close proximity. We demonstrate the potential benefits of such an approach and discuss the many challenges to realizing it in practice: incentivizing cooperation by adequately compensating nodes, effecting such cooperation via an efficient protocol, and facilitating it with a suitable user interface. We present our current thinking on these as we design a collaborative downloading system called COMBINE.
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paper_title: Westwood SCTP: load balancing over multipaths using bandwidth-aware source scheduling

paper_content:

While it is more and more usual to buy computer equipment with multiple network interfaces, and the proliferation of ISPs for both wired and wireless users provides different solutions to access the network core, upper layers across the protocol spectrum seem unprepared to accept the challenge posed by multiple interfaces and, consequently, by multiple paths between the same source-destination pair. This paper tries to partially answer this challenge by proposing an enhancement of the SCTP protocol that aims at balancing load across multiple connections on disjoint paths in an accurate fashion, through the knowledge of bandwidth estimation on each path. Some results confirm the viability of the approach and invite further research.
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paper_title: OSCAR: A Collaborative Bandwidth Aggregation System

paper_content:

The exponential increase in mobile data demand, coupled with growing user expectation to be connected in all places at all times, have introduced novel challenges for researchers to address. Fortunately, the wide spread deployment of various network technologies and the increased adoption of multi-interface enabled devices have enabled researchers to develop solutions for those challenges. Such solutions aim to exploit available interfaces on such devices in both solitary and collaborative forms. These solutions, however, have faced a steep deployment barrier. ::: In this paper, we present OSCAR, a multi-objective, incentive-based, collaborative, and deployable bandwidth aggregation system. We present the OSCAR architecture that does not introduce any intermediate hardware nor require changes to current applications or legacy servers. The OSCAR architecture is designed to automatically estimate the system's context, dynamically schedule various connections and/or packets to different interfaces, be backwards compatible with the current Internet architecture, and provide the user with incentives for collaboration. We also formulate the OSCAR scheduler as a multi-objective, multi-modal scheduler that maximizes system throughput while minimizing energy consumption or financial cost. We evaluate OSCAR via implementation on Linux, as well as via simulation, and compare our results to the current optimal achievable throughput, cost, and energy consumption. Our evaluation shows that, in the throughput maximization mode, we provide up to 150% enhancement in throughput compared to current operating systems, without any changes to legacy servers. Moreover, this performance gain further increases with the availability of connection resume-supporting, or OSCAR-enabled servers, reaching the maximum achievable upper-bound throughput.
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paper_title: Bandwidth aggregation with SCTP

paper_content:

We present a number of modifications to the stream control transmission protocol (SCTP) recently adopted by IETF; they allow bandwidth aggregation over the multiple interfaces of a host. We show that it is possible to implement a number of algorithms for bandwidth aggregation, with only a small number of modifications to the basic SCTP. Our simulation results clearly depict the efficiency of our approach in terms of bandwidth utilization. Furthermore, we implement and evaluate a mechanism for identifying bottlenecks that are shared by flows from the same aggregate connection. Our purpose is to show that SCTP is a good candidate for building a practical protocol for bandwidth aggregation that is fair and supportive of TCP.
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paper_title: BondingPlus: Real-Time Message Channel in Linux Ethernet Environment Using Regular Switching Hub

paper_content:

Bandwidth management is very important to quality of service of network applications. Communications and data transmissions between hosts in a LAN environment may be large in many systems, such as clustering systems and parallel systems. If the network bandwidth is not enough, real-time packets may be delayed and miss their timing constraints. There are many technologies developed to increase host bandwidth in a LAN environment, but most of them need switching hubs with special support such as IEEE Link Aggregation Standard and are very expensive. In this paper, we propose a real-time message channel, BondingPlus, in Linux Ethernet environment which can make use of multiple Ethernet adapters simultaneously between hosts connected with regular switching hubs. When receiving packets from upper network layer, BondingPlus schedules packets in data link layer. Real-time packets can be dispatched into a higher-priority queue so that the packets can be transmitted through the physical Ethernet interface right away. Furthermore, real-time applications can transmit real-time packets via one or several dedicated network adapters which create real-time message channels between hosts and thus reduce transmission delay and jitter dramatically, especially suitable for applications that have high bandwidth and real-time requirements. This approach is implemented in two Linux kernel modules and is backward compatible, flexible and transparent to users. BondingPlus pseudo Ethernet device driver module receives packets from upper network layer and dispatches the packets to multiple physical network adapters with a single IP address. ARP+ protocol module is responsible for maintaining a table of the mapping between an IP address and its corresponding MAC addresses of multiple physical network adapters.
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paper_title: Improving throughput and reliability in mobile wireless networks via transport layer bandwidth aggregation

paper_content:

Currently, most battlefield mobile communication devices are equipped with multiple wireless interfaces. The main target of the multiple interfaces is to increase the communication reliability between the soldiers in the battlefield and the command center, so that if one of the interfaces fails, the other interfaces can still provide a communication path. In this case each application data stream is limited to use only one communication channel. Due to the limited and variable bandwidth of the wireless channels, as well as their lossy and break-prone nature, the performance of mobile applications can be greatly hurt. In this paper, we present a transport layer solution for aggregating the bandwidth of the available interfaces. Our solution is based on extending Stream Control Transmission Protocol (SCTP). Our choice to extend SCTP for bandwidth aggregation was motivated by its inherent support for multi-homing. The extended SCTP, which we refer to as Load Sharing-SCTP (LS-SCTP), is able to aggregate the bandwidth of all the active transmission paths between the communicating endpoints. In addition, LS-SCTP dynamically adds/drops communication paths to the aggregated paths bundle. To ensure that the aggregate connection will not stall due to the high loss rate or continuous failure of individual paths, LS-SCTP includes path monitoring and packet assignment mechanisms that distribute the packets on the paths according to their current condition. Simulation results demonstrate the effectiveness of our proposed mechanism in providing throughput and reliability to mobile applications under battlefield conditions.
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paper_title: Multipath TCP algorithms: theory and design

paper_content:

Multi-path TCP (MP-TCP) has the potential to greatly improve application performance by using multiple paths transparently. We propose a fluid model for a large class of MP-TCP algorithms and identify design criteria that guarantee the existence, uniqueness, and stability of system equilibrium. We characterize algorithm parameters for TCP-friendliness and prove an inevitable tradeoff between responsiveness and friendliness. We discuss the implications of these properties on the behavior of existing algorithms and motivate a new design that generalizes existing algorithms. We use ns2 simulations to evaluate the proposed algorithm and illustrate its superior overall performance.
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paper_title: E2EMPT: A transport layer architecture for end-to-end multipath transfer

paper_content:

With the evolving of the network technology, the number of terminal equipping with multiple network interfaces keeps increasing because of the deploying of various access methods and the price descending of access devices. However, the terminals can not make full use of multiple interfaces concurrently in conversional network. In this paper, we motivate the advantages of simultaneously using multiple interfaces and present a transport layer architecture, E2EMPT, which supports end-to-end multipath transfer. E2EMPT (i) exploits path diversity and distributes data adaptively following characters of the end-toend paths, (ii) reduces the effect of reordering when transferring on multiple end-to-end paths, (iii) implements smart path management policies to select appropriate end-to-end paths. Our evaluation using simulations suggests that E2EMPT aggregates bandwidth of the terminal interfaces efficiently, and meanwhile improves the security and reliability of data transfer.
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paper_title: WTCP: A Reliable Transport Protocol for Wireless Wide-Area Networks

paper_content:

Wireless wide-area networks (WWANs) are characterized by very low and variable bandwidths, very high and variable delays, significant non-congestion related losses, asymmetric uplink and downlink channels, and occasional blackouts. Additionally, the majority of the latency in a WWAN connection is incurred over the wireless link. Under such operating conditions, most contemporary wireless TCP algorithms do not perform very well. In this paper, we present WTCP, a reliable transport protocol that addresses rate control and reliability over commercial WWAN networks such as CDPD. WTCP is rate-based, uses only end-to-end mechanisms, performs rate control at the receiver, and uses inter-packet delays as the primary metric for rate control. We have implemented and evaluated WTCP over the CDPD network, and also simulated it in the ns-2 simulator. Our results indicate that WTCP can improve on the performance of comparable algorithms such as TCP-NewReno, TCP-Vegas, and Snoop-TCP by between 20% to 200% for typical operating conditions.
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paper_title: Binomial congestion control algorithms

paper_content:

This paper introduces and analyzes a class of nonlinear congestion control algorithms called binomial algorithms, motivated in part by the needs of streaming audio and video applications for which a drastic reduction in transmission rate upon each congestion indication (or loss) is problematic. Binomial algorithms generalize TCP-style additive-increase by increasing inversely proportional to a power k of the current window (for TCP, k=0); they generalize TCP-style multiplicative decrease by decreasing proportional to a power l of the current window (for TCP, l=1). We show that there are an infinite number of deployable TCP-compatible binomial algorithms, those which satisfy k+1=1, and that all binomial algorithms converge to fairness under a synchronized-feedback assumption provided k+l>0; k, l/spl ges/0. Our simulation results show that binomial algorithms interact well with TCP across a RED gateway. We focus on two particular algorithms, IIAD (k=1, l=0) and SQRT (k=l=0.5), showing that they are well-suited to applications that do not react well to large TCP-style window reductions.
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paper_title: Cross-layer FPS: A SCTP-based cross-layer data scheduling approach

paper_content:

In heterogeneous wireless networks, multi-interfaced mobile terminals may be connected to links with rapidly varying MAC and physical characteristics. On the other hand, current deployment of communication protocols rely on the information available at associated layer only. In order to improve transport layer performance for multi-homed mobile terminals, we propose a cross-layer approach to schedule data over multiple available paths. Our data-striping approach strengthens the cooperation between higher and lower layers and enables transport layer mechanism to exploit information provided by MAC layer. We compare our approach with existing techniques and prove that our cross-layer system improves multipath performance over single-layer multipath systems.
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paper_title: Transport level mechanisms for bandwidth aggregation on mobile hosts

paper_content:

Present mobile computing does not support the simultaneous use of multiple heterogeneous network interfaces for a single transport layer connection. We describe a solution for channel aggregation at the transport layer, which provides increased bandwidth to mobile nodes. We present R-MTP (reliable multiplexing transport protocol), a rate-based reliable transport protocol capable of multiplexing data from a single application data stream across multiple network interfaces. Due to the lossy nature of wireless links in mobile environments, R-MTP tracks packet interarrival time for discrimination between congestion-based and transmission-based losses as well as better bandwidth estimation. The challenges to such a reliable protocol lie in the coordination of packets across streams with varying channel characteristics. Our experimental results validate R-MTP's bandwidth estimation and loss characterization techniques. Successful bandwidth aggregation is demonstrated in ideal and lossy environments.
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paper_title: A Data-Scheduling Mechanism for Multi-Homed Mobile Terminals with Disparate Link Latencies

paper_content:

A mobile terminal equipped with multiple network interfaces can often be found under coverage of multiple access networks. Multihoming enables mobile terminals to communicate simultaneously through multiple interfaces. Connection-oriented transport layer mechanisms ensure reliable, in-order delivery of data, however parallel data transfers in multihoming face problems due to out-of-order reception of data which causes fast-retransmissions and limit the communication throughput. In this paper, we propose a transport layer based mechanism which stripes one flow''s data across multiple disjoint paths efficiently, reducing possible occurrence of out-of-order data. Our mechanism estimates arrival times of data packets to be sent through available paths in an association, and decides which packets are to be sent through each path. We compared our mechanism with a relatively closer approach called Westwood SCTP. We illustrate with the help of simulation results that our mechanism proves to improve multipath communication.
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paper_title: A Compound TCP Approach for High-Speed and Long Distance Networks

paper_content:

Many applications require fast data transfer over high speed and long distance networks. However, standard TCP fails to fully utilize the network capacity due to the limitation in its conservative congestion control (CC) algorithm. Some works have been proposed to improve the connection 鈂s throughput by adopt- ing more aggressive loss-based CC algorithms. These algorithms, although can effectively improve the link utilization, have the weakness of poor RTT fairness. Further, they may severely de- crease the performance of regular TCP flows that traverse the same network path. On the other hand, pure delay-based ap- proaches that improve the throughput in high-speed networks may not work well when the traffic is mixed with both delay- based and greedy loss-based flows. In this paper, we propose a novel Compound TCP (CTCP) approach, which is a synergy of delay-based and loss-based approach. Specifically, we add a scal- able delay-based component into the standard TCP Reno conges- tion avoidance algorithm (a.k.a., the loss-based component). The sending rate of CTCP is controlled by both components. This new delay-based component can rapidly increase sending rate when network path is under utilized, but gracefully retreat in a busy network when bottleneck queue is built. Augmented with this delay-based component, CTCP provides very good bandwidth scalability with improved RTT fairness, and at the same time achieves good TCP-fairness, irrelevant to the windows size. We developed an analytical model of CTCP and implemented it on the Windows operating system. Our analysis and experiment results verify the properties of CTCP.
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paper_title: The Design of Mobile Concurrent Multipath Transfer in Multihomed Wireless Mobile Networks

paper_content:

As more and more devices are equipped with multiple network interfaces, the multihomed technology is becoming an important technology that can provide more reliable connection against the network failure and higher data transmission rate. Concurrent Multipath Transfer (CMT), which is based on SCTP, is devised for multihomed networks. CMT can transmit data over all paths to maximize the data transmission speed. One of the main concerns of CMT is the receiver buffer blocking issue, especially in multihomed wireless mobile networks. Receiver buffer blocking is mainly caused by lost data. In this paper, we propose mobile CMT (mCMT) over wireless networks to deal with the receiver buffer blocking caused by error loss and handoff loss. mCMT has the features of (i) path-oriented multistreaming, (ii) MIH-assisted handoff mechanism, in which MIH denotes Media Independent Handover and (iii) association resume. Path-oriented multistreaming can reduce the receiver buffer blocking caused by error loss. MIH-assisted a handoff can reduce the amount of packet loss during a handoff, which may lead to receiver buffer blocking. Moreover, mCMT introduces the concept of association resume to recover the disconnected association. Simulation results show that mCMT can reduce the effect of the receiver buffer blocking effectively for devices that have smaller buffer size.
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paper_title: A Transport Layer Approach for Improving End-to-End Performance and Robustness Using Redundant Paths

paper_content:

Recent work on Internet measurement and overlay networks has shown that redundant paths are common between pairs of hosts and that one can often achieve better end-to-end performance by adaptively choosing an alternate path [8, 28]. In this paper, we propose an end-to-end transport layer protocol, mTCP, which can aggregate the available bandwidth of those redundant paths in parallel. By striping one flow's packets across multiple paths, mTCP can not only obtain higher end-to-end throughput but also become more robust under path failures. When some paths fail, mTCP can continue sending packets on other living paths and the recovery process normally takes only a few seconds. Because mTCP could obtain an unfair share of bandwidth under shared congestion, we integrate a shared congestion detection mechanism into our system. It allows us to dynamically detect and suppress paths with shared congestion so as to alleviate the aggressiveness problem. mTCP can also passively monitor the performance of several paths in parallel and discover better paths than the path provided by the underlying routing infrastructure. We also propose a heuristic to find disjoint paths between pairs of nodes using traceroute. We have implemented our system on top of overlay networks and evaluated it in both Planet-Lab and Emulab.
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paper_title: Improved data distribution for multipath TCP communication

paper_content:

Multi-homed environments are increasingly common, especially for mobile users. To efficiently utilize multiple access lines for single file transfer, multipath TCP communication methods have been proposed. A multipath TCP enables simultaneous distributed data transfer between two end-points on multiple TCP connections. However, these methods cannot fully utilize the available bandwidth of multiple paths because they do not properly consider the end-to-end delay of packet transmission, so out-of-order data arrival at a receiver causes a bottleneck in data sort operations. This problem is more severe in environments where the quality of each path is different or unstable, such as in wireless environments. To solve this problem, we propose a multipath TCP communication method that includes a data distribution method to enable in-order delivery at a receiver. We call this arrival-time matching load-balancing (ATLB). ATLB continuously calculates the delay of each path, including the TCP queuing delay at a sender and the network delay, and then sends a data segment through the TCP connection with the lowest end-to-end delay. Simulation results show that ATLB improves end-to-end throughput, especially in heterogeneous environments where the quality of paths differs. For example, ATLB enabled twice the throughput with the conventional multipath TCP. We also report performance evaluation results from our ATLB test bed system in a wireless network environment. Our ATLB test bed system was able to fully utilize the aggregate available bandwidth of unstable multiple wireless links.
---
paper_title: LS-SCTP: a bandwidth aggregation technique for stream control transmission protocol

paper_content:

Stream Control Transmission Protocol (SCTP) specifications utilize the multiple paths capabilities between the sender and receiver for retransmission of lost data chunks and as a backup in case of primary path failure. Under normal conditions, all data chunks are sent on the primary path chosen by the SCTP user during the transport connection initiation. In this paper, we address in detail various aspects related to extending and engineering SCTP in order to utilize the available paths for simultaneous transmission of data chunks, while maintaining the SCTP congestion control on each path so as to ensure fair integration with other traffic in the network. The extended SCTP, referred to as Load-Sharing SCTP (LS-SCTP), is able to aggregate the bandwidth of all the active transmission paths between the communicating endpoints. LS-SCTP monitors the paths, and accordingly it chooses the paths that are suitable for load sharing. LS-SCTP retransmission mechanism accelerates the delivery of missing data to the receiver in order to prevent stalling the transport connection while waiting for missing data chunks. Simulation results show that LS-SCTP is extremely beneficial for networks with limited bandwidth, high loss rate and failure prone links.
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paper_title: CUBIC: a new TCP-friendly high-speed TCP variant

paper_content:

CUBIC is a congestion control protocol for TCP (transmission control protocol) and the current default TCP algorithm in Linux. The protocol modifies the linear window growth function of existing TCP standards to be a cubic function in order to improve the scalability of TCP over fast and long distance networks. It also achieves more equitable bandwidth allocations among flows with different RTTs (round trip times) by making the window growth to be independent of RTT -- thus those flows grow their congestion window at the same rate. During steady state, CUBIC increases the window size aggressively when the window is far from the saturation point, and the slowly when it is close to the saturation point. This feature allows CUBIC to be very scalable when the bandwidth and delay product of the network is large, and at the same time, be highly stable and also fair to standard TCP flows. The implementation of CUBIC in Linux has gone through several upgrades. This paper documents its design, implementation, performance and evolution as the default TCP algorithm of Linux.
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paper_title: QoS-oriented MPTCP Extensions for Multimedia Multi-homed Systems

paper_content:

The increasing number of interfaces using different access technologies in modern devices gives opportunities for enhancing the Quality of Service (QoS) delivered to multimedia and interactive data transfers involved in distributed applications. In the current Internet, the presence of "middleboxes" such as Network Address Translators (NAT) or firewalls hardly lets applications use any Transport protocol but the well-known Transmission Control Protocol (TCP). Currently under standardization at the IETF, the new Multipath-TCP (MPTCP) protocol uses several TCP flows to make use of the multiple interfaces available on the end terminals, thus improving both network availability and QoS, still being capable to cross over middle boxes. Although originally being fully reliable and fully ordered, its two sub-layers architecture gives opportunity to use QoS techniques over fully reliable paths. This paper studies the QoS benefits induced by the implementation of the "partial reliability" concept in MPTCP for interactive video applications. Two different mechanisms are experimented with the aim to enhance global quality of video transmission over paths close to 3G networks characteristics. The Internet Engineering Task Force (IETF) MPTCP working group's ns-2 implementation is used for the experimentations. The Evalvid toolkit over ns-2 is used to measure the QoS benefits expressed in terms of Peak Signal to Noise Ratio (PSNR).
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paper_title: pTCP: an end-to-end transport layer protocol for striped connections

paper_content:

The TCP transport layer protocol is designed for connections that traverse a single path between the sender and receiver. However there are several environments in which multiple paths can be used by a connection simultaneously. We consider the problem of supporting striped connections that operate over multiple paths. We propose an end-to-end transport layer protocol called pTCP (parallel TCP) that allows connections to enjoy the aggregate bandwidths offered by the multiple paths, irrespective of the individual characteristics of the paths. We show that pTCP can have a varied range of applications through instantiations in three different environments: (a) bandwidth aggregation on multi-homed mobile hosts; (b) service differentiation using purely end-to-end mechanisms; (c) end-systems based network striping. In each of the applications, we demonstrate the applicability of pTCP and how its efficacy compares with existing approaches through simulation results.
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paper_title: Westwood SCTP: load balancing over multipaths using bandwidth-aware source scheduling

paper_content:

While it is more and more usual to buy computer equipment with multiple network interfaces, and the proliferation of ISPs for both wired and wireless users provides different solutions to access the network core, upper layers across the protocol spectrum seem unprepared to accept the challenge posed by multiple interfaces and, consequently, by multiple paths between the same source-destination pair. This paper tries to partially answer this challenge by proposing an enhancement of the SCTP protocol that aims at balancing load across multiple connections on disjoint paths in an accurate fashion, through the knowledge of bandwidth estimation on each path. Some results confirm the viability of the approach and invite further research.
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paper_title: cmpSCTP: An Extension of SCTP to Support Concurrent Multi-Path Transfer

paper_content:

This paper introduced cmpSCTP, a transport layer solution for concurrent multi-path transfer that modifies the standard Stream Control Transmission Protocol (SCTP). The cmpSCTP aims at exploiting SCTP's multi-homing capability by selecting several best paths among multiple available network interfaces to improve data transfer rate to the same multi-homed device. Through the use of path monitoring and packet allotment techniques, cmpSCTP tries to transmit given amount of packets at corresponding path as its ability. At the same time, cmpSCTP updates the transmission strategy based on the real-time information of all of paths. Using cmpSCTP's flexible path management capability, we may switch the flow between multiple paths automatically to realize seamless path handover. Extensive simulations under different scenarios using OPNET verified that cmpSCTP can effectively enhance transmission efficiency and highlighted the superiority of cmpSCTP against the other SCTP's extension implementations under performance indexes such as throughput, handover latency, packet delay, and packet loss.
---
paper_title: A Concurrent Multipath TCP and Its Markov Model

paper_content:

Concurrent Multipath Transport (CMT) has been of increasing interest recently for aggregating bandwidth, balancing load, and increasing reliability. In this paper we propose a concurrent multipath Transport Control Protocol (cmpTCP), which is an extension of TCP New Reno and Steam Control Transmission Protocol (SCTP). The proposed cmpTCP has been implemented by altering and extending library-based open-source for SCTP. The proposed cmpTCP manages transport control parameters of all paths simultaneously; a scheduler concurrently dispatches packets over all the paths from a common transmission queue. However, one virtual retransmission queue is maintained for each path, and the receiver sends acknowledgment for a packet on the same path on which the packet is received. A Markov model for estimation of expected window size of each path has been proposed. Next, the proposed model has been utilized to derive an expression for computing average data transmission rate when the proposed cmpTCP is used. To validate performance of the proposed model, two host computers were connected through two independent network emulators. Each network emulator runs on a separate computer, and the network parameters are adjusted independently. We used our cmpTCP for transferring files from one host to the other. Comparison of experimental results with model predicted results shows excellent agreement.
---
paper_title: MPSCTP: A multipath variant of SCTP and its performance comparison with other multipath protocols

paper_content:

Multipath protocols have great potential to improve error resilience and utilization of scarce network resources. In 2000, IETF introduced Stream Control Transmission Protocol (SCTP) for multihomed transport. Concurrent Multipath Transfer (CMT) and Multipath SCTP (MPSCTP) were proposed as extensions of SCTP to support concurrent usage of available paths. Our original MPSCTP proposal assumes that all the paths between the source and the destination are disjoint and there is no acknowledgement loss in the reverse direction. In this paper we propose a generalized version of the MPSCTP protocol where these assumptions are relaxed. We also present a comparative study of the performance of MPSCTP with CMT and MPTCP, a multipath variant of TCP, in different network scenarios using ns-2 based simulations.
---
paper_title: TCP westwood: Bandwidth estimation for enhanced transport over wireless links

paper_content:

TCP Westwood (TCPW) is a sender-side modification of the TCP congestion window algorithm that improves upon the performance of TCP Reno in wired as well as wireless networks. The improvement is most significant in wireless networks with lossy links, since TCP Westwood relies on end-to-end bandwidth estimation to discriminate the cause of packet loss (congestion or wireless channel effect) which is a major problem in TCP Reno. An important distinguishing feature of TCP Westwood with respect to previous wireless TCP “extensions” is that it does not require inspection and/or interception of TCP packets at intermediate (proxy) nodes. Rather, it fully complies with the end-to-end TCP design principle. The key innovative idea is to continuously measure at the TCP source the rate of the connection by monitoring the rate of returning ACKs. The estimate is then used to compute congestion window and slow start threshold after a congestion episode, that is, after three duplicate acknowledgments or after a timeout. The rationale of this strategy is simple: in contrast with TCP Reno, which “blindly” halves the congestion window after three duplicate ACKs, TCP Westwood attempts to select a slow start threshold and a congestion window which are consistent with the effective bandwidth used at the time congestion is experienced. We call this mechanism faster recovery. The proposed mechanism is particularly effective over wireless links where sporadic losses due to radio channel problems are often misinterpreted as a symptom of congestion by current TCP schemes and thus lead to an unnecessary window reduction. Experimental studies reveal improvements in throughput performance, as well as in fairness. In addition, friendliness with TCP Reno was observed in a set of experiments showing that TCP Reno connections are not starved by TCPW connections. Most importantly, TCPW is extremely effective in mixed wired and wireless networks where throughput improvements of up to 550% are observed. Finally, TCPW performs almost as well as localized link layer approaches such as the popular Snoop scheme, without incurring the O/H of a specialized link layer protocol.
---
paper_title: Binary increase congestion control (BIC) for fast long-distance networks

paper_content:

High-speed networks with large delays present a unique environment where TCP may have a problem utilizing the full bandwidth. Several congestion control proposals have been suggested to remedy this problem. The existing protocols consider mainly two properties: TCP friendliness and bandwidth scalability. That is, a protocol should not take away too much bandwidth from standard TCP flows while utilizing the full bandwidth of high-speed networks. This work presents another important constraint, namely, RTT (round trip time) unfairness where competing flows with different RTTs may consume vastly unfair bandwidth shares. Existing schemes have a severe RTT unfairness problem because the congestion window increase rate gets larger as the window grows ironically the very reason that makes them more scalable. RTT unfairness for high-speed networks occurs distinctly with drop tail routers for flows with large congestion windows where packet loss can be highly synchronized. After identifying the RTT unfairness problem of existing protocols, This work presents a new congestion control scheme that alleviates RTT unfairness while supporting TCP friendliness and bandwidth scalability. The proposed congestion control algorithm uses two window size control policies called additive increase and binary search increase. When the congestion window is large, additive increase with a large increment ensures square RTT unfairness as well as good scalability. Under small congestion windows, binary search increase supports TCP friendliness. The simulation results confirm these properties of the protocol.
---
paper_title: A Multipath Cubic TCP Congestion Control with Multipath Fast Recovery over High Bandwidth-Delay Product Networks

paper_content:

Cubic TCP, one of transport protocols designed for high bandwidth-delay product (BDP) networks, has successfully been deployed in the Internet. Multi-homed computers with multiple interfaces to access the Internet via high speed links will become more popular. In this work, we introduce an extended version of Cubic TCP for multiple paths, called MPCubic. The extension process is approached from an analysis model of Cubic by using coordinated congestion control between paths. MPCubic can spread its traffic across paths in load-balancing manner, while preserving fair sharing with regular TCP, Cubic, and MPTCP at common bottlenecks. Moreover, to improve resilience to link failure, we propose a multipath fast recovery algorithm. The algorithm can significantly reduce the recovery time of data rate after restoration of failed links. These techniques can be useful for resilient high-bandwidth applications (for example, tele-health conference) in disaster-affected areas. Our simulation results show that MPCubic can achieve stability, throughput improvement, fairness, load-balancing, and quick data rate recovery from link failure under a variety of network conditions. key words: multipath congestion control, Cubic TCP for multiple paths, load-balancing, resource pooling, fairness, resilience, disaster
---
paper_title: Multipath Binomial Congestion Control Algorithms

paper_content:

Nowadays portable devices with multiple wireless interfaces and using multimedia services are becoming more popular on the Internet. This paper describes a family of multipath binomial congestion control algorithms for audio/video streaming, where a low variant of transmission rate is important. We extend the fluid model of binomial algorithms for single-path transmission to support the concurrent transmission of packets across multiple paths. We focus on the extension of two particular algorithms, SQRT and IIAD, for multiple paths, called MPSQRT and MPIIAD, respectively. Additionally, we apply the design technique (using the multipath fluid model) for multipath TCP (MPTCP) into the extension of SQRT and IIAD, called fbMPSQRT and fbMPIIAD, respectively. Both two approaches ensure that multipath binomial congestion control algorithms achieve load-balancing, throughput improvement, and fairness to single-path binomial algorithms at shared bottlenecks. Through the simulations and comparison with the uncoordinated protocols MPSQRT/MPIIAD, fbMPSQRT/fbMPIIAD and MPTCP, we find that our extended multipath transport protocols can preserve lower latency and transmission rate variance than MPTCP, fairly share with single-path SQRT/IIAD, MPTCP and TCP, and also can achieve throughput improvements and load-balancing equivalent to those of MPTCP under various scenarios and network conditions. key words: multipath binomial congestion control, multimedia streaming, fairness, load-balancing
---
paper_title: Design, implementation and evaluation of congestion control for multipath TCP

paper_content:

Multipath TCP, as proposed by the IETF working group mptcp, allows a single data stream to be split across multiple paths. This has obvious benefits for reliability, and it can also lead to more efficient use of networked resources. We describe the design of a multipath congestion control algorithm, we implement it in Linux, and we evaluate it for multihomed servers, data centers and mobile clients. We show that some 'obvious' solutions for multipath congestion control can be harmful, but that our algorithm improves throughput and fairness compared to single-path TCP. Our algorithmis a drop-in replacement for TCP, and we believe it is safe to deploy.
---
paper_title: Bandwidth aggregation with SCTP

paper_content:

We present a number of modifications to the stream control transmission protocol (SCTP) recently adopted by IETF; they allow bandwidth aggregation over the multiple interfaces of a host. We show that it is possible to implement a number of algorithms for bandwidth aggregation, with only a small number of modifications to the basic SCTP. Our simulation results clearly depict the efficiency of our approach in terms of bandwidth utilization. Furthermore, we implement and evaluate a mechanism for identifying bottlenecks that are shared by flows from the same aggregate connection. Our purpose is to show that SCTP is a good candidate for building a practical protocol for bandwidth aggregation that is fair and supportive of TCP.
---
paper_title: Multi-Path Load Balancing in Transport Layer

paper_content:

In this paper, we propose an extension to current TCP protocol named concurrent TCP (cTCP), which can improve throughput of connections through balancing traffic load on multiple end-to-end paths. We keep the single-sliding-window architecture of TCP untouched for compatibility reasons. The two core components of the design are a packet scheduling switch that balances load among paths, and a duplicated acknowledgement classifier that handles packet reordering. We implemented our protocol in FreeBSD kernel and compared the performance of cTCP with theoretical results. Experiment outcomes show that throughputs of our protocol are close to the ideal values.
---
paper_title: Feasibility considerations of multipath TCP in dealing with big data application

paper_content:

In this paper we present an idea to handle big data in a better way. We consider Multipath TCP (MPTCP) to use all available paths simultaneously. MPTCP is a tailored form of TCP which aspire to improve throughput by sharing available resources smartly and fairly. The key concentration of this paper is to analyze the benefit of MPTCP over single path TCP for bandwidth and time sensitive applications as well as big data application. Our simulation shows that MPTCP can higher goodput by bandwidth aggregation, Couple Congestion Control(CCC) provide better throughput without being unfair to other legacy TCP flows and also portray that large receive buffer causes performance enhancement for relatively large RTT link. As a result, MPTCP can be a enormous addition in contrast with single path TCP in dealing with big data application.
---
paper_title: A Network Layer Approach to Enable TCP over Multiple Interfaces

paper_content:

The mobile Internet is set to become ubiquitous with the deployment of various wireless technologies. When heterogeneous wireless networks overlap in coverage, a mobile terminal can potentially use multiple wireless interfaces simultaneously. In this paper, we motivate the advantages of simultaneous use of multiple interfaces and present a network layer architecture that supports diverse multi-access services. Our main focus is on one such service provided by the architecture: Bandwidth Aggregation (BAG), specifically for TCP applications.While aggregating bandwidth across multiple interfaces can improve raw throughput, it introduces challenges in the form of packet reordering for TCP applications. When packets are reordered, TCP misinterprets the duplicate ACKS received as indicative of packet loss and invokes congestion control. This can significantly lower TCP throughput and counter any gains that can be had through bandwidth aggregation. To improve overall performance of TCP, we take a two-pronged approach: (1) We propose a scheduling algorithm that partitions traffic onto the different paths (corresponding to each interface) such that reordering is minimized. The algorithm estimates available bandwidth and thereby minimizes reordering by sending packet pairs on the path that introduces the least amount of delay. (2) A buffer management policy is introduced at the client to hide any residual reordering from TCP. We show through simulations that our network-layer approach can achieve good bandwidth aggregation under a variety of network conditions.
---
paper_title: MOTA: engineering an operator agnostic mobile service

paper_content:

There are two emerging trends in the mobile data world. First, mobile data is exploding at a rapid rate with analysts predicting 25-50X growth by the year 2015. The second trend is that users are demanding greater degree of flexibility in selecting their operators at fine timescales. Across Asia, dual-SIM phones have become popular, while Apple is rumored to be designing a Universal SIM that will allow iPhone users to toggle between different operators. This latter trend points towards an impending disruption in wireless service models which could also be the need of the hour from the spectrum shortage perspective. This points towards a new service model where users can choose an operator based on application needs. However, if users make this choice greedily without network assistance, it can exacerbate spectrum scarcity and degrade user experience. In this work, we consider user devices with multiple network interfaces (3G, LTE etc.) that can be simultaneously active and each running multiple applications. We propose the MOTA service model to enable users to associate each interface with the operator of choice at fine time scales. Under the MOTA service model, through concise signalling information, operators provide information about their own network, so that each user can (i) choose a suitable operator for each interface, and (ii) choose an interface for each active application. We make the following contributions in this paper. First, we propose concise network signalling that assists users to make informed choices even under mobility. Second, we develop user-choice algorithms that maximize a suitable notion of user satisfaction while using spectrum resources efficiently. Third, we perform extensive evaluation over actual base station deployment in a city coupled with real signal propagation maps. Our results with two operators show that, MOTA service model provides capacity gain in the range 2.5-4X over the current existing service model. Finally, we argue that our solution is practically implementable by combining appropriate IEEE standards and IETF proposals.
---
paper_title: MAR: a commuter router infrastructure for the mobile Internet

paper_content:

We introduce MAR, a commuter mobile access router infrastructure that exploits wireless diversity (e.g. channel diversity, network diversity, and technology diversity) to provide improved data performance for wireless data users. Our system design stems from the observation that rather than choosing a single wireless service provider (e.g. Sprint, AT&T, BT, Vodafone), a single technology (e.g. GPRS, UMTS, CDMA, 802.11), or a single wireless channel, users can obtain significant benefits by using the multiplicity of choices available. MAR is a wireless multi-homed device that can be placed in moving vehicles (e.g. car, bus, train) to enable high-speed data access. MAR dynamically instantiates new channels based on traffic demand, aggregates the bandwidth and dynamically shifts load from poor quality to better quality channels. MAR, thus, provides a faster, more stable, and reliable communication channel to mobile users.We have implemented and tested the MAR system in our testbed which spans the networks of three different cellular providers. Through our experiments we have performed a detailed evaluation to quantify the benefits of MAR for different protocols and applications. For example, even in highly mobile environments, MAR, on average, improves the end-user experience of web-browsing and streaming applications by a factor of 2.8 and 4.4 respectively. Our results show that significant benefits can be obtained by exploiting the diversity in coverage offered by many cellular operators, different technology networks (e.g. GPRS, CDMA), and diverse wireless channels.
---
paper_title: A novel mechanism for data streaming across multiple IP links for improving throughput and reliability in mobile environments

paper_content:

With ubiquitous computing and network access, multiple network conduits are becoming available to mobile as well as static hosts. Selection of the preferred mode of data transfer is a dynamic optimization problem depending on the type of application, its bandwidth/latency/jitter requirements, current network status, cost, power consumption, battery life, and so on. Furthermore, since wireless bandwidth is likely to remain a scarce resource, we foresee scenarios wherein mobile hosts require simultaneous data transfer across multiple IP interfaces to obtain higher overall bandwidth. We present a brief overview of related work identifying schemes that might be applicable to the problem, along with their feasibility, and pros and cons. We then propose a new mechanism to aggregate the bandwidth of multiple IP links by splitting a data flow across multiple network interfaces at the IP level. Our method is transparent to transport (TCP/UDP) and higher layers. We have analyzed the performance characteristics of the aggregation scheme and demonstrated significant gain when the links being aggregated have similar bandwidth and latency. The use of multiple interfaces also enhances reliability. Our analysis identifies the conditions under which the proposed scheme, or any other scheme that stripes a single TCP connection across multiple IP links, can be used to enhance throughput. Several interesting directions for future work have also been identified.
---
paper_title: Host Identity Protocol (HIP): Connectivity, Mobility, Multi-Homing, Security, and Privacy over IPv4 and IPv6 Networks

paper_content:

The Host Identity Protocol (HIP) is an inter-networking architecture and an associated set of protocols, developed at the IETF since 1999 and reaching their first stable version in 2007. HIP enhances the original Internet architecture by adding a name space used between the IP layer and the transport protocols. This new name space consists of cryptographic identifiers, thereby implementing the so-called identifier/locator split. In the new architecture, the new identifiers are used in naming application level end-points (sockets), replacing the prior identification role of IP addresses in applications, sockets, TCP connections, and UDP-based send and receive system calls. IPv4 and IPv6 addresses are still used, but only as names for topological locations in the network. HIP can be deployed such that no changes are needed in applications or routers. Almost all pre-compiled legacy applications continue to work, without modifications, for communicating with both HIP-enabled and non-HIP-enabled peer hosts. The architectural enhancement implemented by HIP has profound consequences. A number of the previously hard networking problems become suddenly much easier. Mobility, multi-homing, and baseline end-to-end security integrate neatly into the new architecture. The use of cryptographic identifiers allows enhanced accountability, thereby providing a base for easier build up of trust. With privacy enhancements, HIP allows good location anonymity, assuring strong identity only towards relevant trusted parties. Finally, the HIP protocols have been carefully designed to take middle boxes into account, providing for overlay networks and enterprise deployment concerns. This article provides an in-depth look at HIP, discussing its architecture, design, benefits, potential drawbacks, and ongoing work.
---
paper_title: OSCAR: A Collaborative Bandwidth Aggregation System

paper_content:

The exponential increase in mobile data demand, coupled with growing user expectation to be connected in all places at all times, have introduced novel challenges for researchers to address. Fortunately, the wide spread deployment of various network technologies and the increased adoption of multi-interface enabled devices have enabled researchers to develop solutions for those challenges. Such solutions aim to exploit available interfaces on such devices in both solitary and collaborative forms. These solutions, however, have faced a steep deployment barrier. ::: In this paper, we present OSCAR, a multi-objective, incentive-based, collaborative, and deployable bandwidth aggregation system. We present the OSCAR architecture that does not introduce any intermediate hardware nor require changes to current applications or legacy servers. The OSCAR architecture is designed to automatically estimate the system's context, dynamically schedule various connections and/or packets to different interfaces, be backwards compatible with the current Internet architecture, and provide the user with incentives for collaboration. We also formulate the OSCAR scheduler as a multi-objective, multi-modal scheduler that maximizes system throughput while minimizing energy consumption or financial cost. We evaluate OSCAR via implementation on Linux, as well as via simulation, and compare our results to the current optimal achievable throughput, cost, and energy consumption. Our evaluation shows that, in the throughput maximization mode, we provide up to 150% enhancement in throughput compared to current operating systems, without any changes to legacy servers. Moreover, this performance gain further increases with the availability of connection resume-supporting, or OSCAR-enabled servers, reaching the maximum achievable upper-bound throughput.
---
paper_title: Improving TCP performance over an on-board multi-homed network

paper_content:

Previously, a multi-homed NEMO architecture has been proposed to improve the reliability and aggregate the bandwidth of MR by simultaneously using multiple wireless links. In this work, we propose a novel protocol called ETOM (Enhancements for TCP On a Multi-homed mobile router) to improve the performance of sending a single TCP connection over multiple wireless links on a MR. ETOM consists of three components. First, we use a reordering buffer to eliminate unnecessary retransmission caused by out-of-order packets. Second, we develop a Multi-homed Split Connection mechanism to enable the TCP connection to quickly adapt to the conditions of multiple links when packet loss occurs. Finally, a Scheduled Window-based Transmission Control algorithm is proposed to mitigate the negative effects of out-of-order packets in the case of using heterogeneous links in a multi-homed environment. We evaluate the performance of ETOM by comparing it with the Concurrent Multi-path Transfer SCTP (CMT-SCTP). ETOM resolves several performance issues that could hinder the development and practical application of multi-homed mobile router technology.
---
paper_title: A Network Layer Approach to Enable TCP over Multiple Interfaces

paper_content:

The mobile Internet is set to become ubiquitous with the deployment of various wireless technologies. When heterogeneous wireless networks overlap in coverage, a mobile terminal can potentially use multiple wireless interfaces simultaneously. In this paper, we motivate the advantages of simultaneous use of multiple interfaces and present a network layer architecture that supports diverse multi-access services. Our main focus is on one such service provided by the architecture: Bandwidth Aggregation (BAG), specifically for TCP applications.While aggregating bandwidth across multiple interfaces can improve raw throughput, it introduces challenges in the form of packet reordering for TCP applications. When packets are reordered, TCP misinterprets the duplicate ACKS received as indicative of packet loss and invokes congestion control. This can significantly lower TCP throughput and counter any gains that can be had through bandwidth aggregation. To improve overall performance of TCP, we take a two-pronged approach: (1) We propose a scheduling algorithm that partitions traffic onto the different paths (corresponding to each interface) such that reordering is minimized. The algorithm estimates available bandwidth and thereby minimizes reordering by sending packet pairs on the path that introduces the least amount of delay. (2) A buffer management policy is introduced at the client to hide any residual reordering from TCP. We show through simulations that our network-layer approach can achieve good bandwidth aggregation under a variety of network conditions.
---
paper_title: MAR: a commuter router infrastructure for the mobile Internet

paper_content:

We introduce MAR, a commuter mobile access router infrastructure that exploits wireless diversity (e.g. channel diversity, network diversity, and technology diversity) to provide improved data performance for wireless data users. Our system design stems from the observation that rather than choosing a single wireless service provider (e.g. Sprint, AT&T, BT, Vodafone), a single technology (e.g. GPRS, UMTS, CDMA, 802.11), or a single wireless channel, users can obtain significant benefits by using the multiplicity of choices available. MAR is a wireless multi-homed device that can be placed in moving vehicles (e.g. car, bus, train) to enable high-speed data access. MAR dynamically instantiates new channels based on traffic demand, aggregates the bandwidth and dynamically shifts load from poor quality to better quality channels. MAR, thus, provides a faster, more stable, and reliable communication channel to mobile users.We have implemented and tested the MAR system in our testbed which spans the networks of three different cellular providers. Through our experiments we have performed a detailed evaluation to quantify the benefits of MAR for different protocols and applications. For example, even in highly mobile environments, MAR, on average, improves the end-user experience of web-browsing and streaming applications by a factor of 2.8 and 4.4 respectively. Our results show that significant benefits can be obtained by exploiting the diversity in coverage offered by many cellular operators, different technology networks (e.g. GPRS, CDMA), and diverse wireless channels.
---
paper_title: INTELiCON: A Framework for the Simultaneous Utilization of Multiple Interfaces and its Application on TCP

paper_content:

Widespread deployment of Wi-Fi together with 3G upgrades to cellular networks is rapidly creating areas where multiple wireless IP technologies will coexist. WiMAX will further contribute to this phenomenon. The ability to use diverse access technologies simultaneously creates opportunities to improve application service quality and reliability. In this paper, we present an intelligent connectivity framework (INTELiCON) that allows devices to exploit access diversity in new ways. INTELiCON provides a modular, flexible platform for discovering, selecting, executing and evaluating the most appropriate transmission strategies over multiple interfaces while maintaining transparency to both the application and the link layers. We present the architectural characteristics of the INTELiCON framework and describe a prototype proof-of-concept implementation. Indicatively, we show how the framework exploits access diversity to improve TCP-based transmission despite limited resources and unreliable links.
---
paper_title: A novel mechanism for data streaming across multiple IP links for improving throughput and reliability in mobile environments

paper_content:

With ubiquitous computing and network access, multiple network conduits are becoming available to mobile as well as static hosts. Selection of the preferred mode of data transfer is a dynamic optimization problem depending on the type of application, its bandwidth/latency/jitter requirements, current network status, cost, power consumption, battery life, and so on. Furthermore, since wireless bandwidth is likely to remain a scarce resource, we foresee scenarios wherein mobile hosts require simultaneous data transfer across multiple IP interfaces to obtain higher overall bandwidth. We present a brief overview of related work identifying schemes that might be applicable to the problem, along with their feasibility, and pros and cons. We then propose a new mechanism to aggregate the bandwidth of multiple IP links by splitting a data flow across multiple network interfaces at the IP level. Our method is transparent to transport (TCP/UDP) and higher layers. We have analyzed the performance characteristics of the aggregation scheme and demonstrated significant gain when the links being aggregated have similar bandwidth and latency. The use of multiple interfaces also enhances reliability. Our analysis identifies the conditions under which the proposed scheme, or any other scheme that stripes a single TCP connection across multiple IP links, can be used to enhance throughput. Several interesting directions for future work have also been identified.
---
paper_title: OSCAR: A Collaborative Bandwidth Aggregation System

paper_content:

The exponential increase in mobile data demand, coupled with growing user expectation to be connected in all places at all times, have introduced novel challenges for researchers to address. Fortunately, the wide spread deployment of various network technologies and the increased adoption of multi-interface enabled devices have enabled researchers to develop solutions for those challenges. Such solutions aim to exploit available interfaces on such devices in both solitary and collaborative forms. These solutions, however, have faced a steep deployment barrier. ::: In this paper, we present OSCAR, a multi-objective, incentive-based, collaborative, and deployable bandwidth aggregation system. We present the OSCAR architecture that does not introduce any intermediate hardware nor require changes to current applications or legacy servers. The OSCAR architecture is designed to automatically estimate the system's context, dynamically schedule various connections and/or packets to different interfaces, be backwards compatible with the current Internet architecture, and provide the user with incentives for collaboration. We also formulate the OSCAR scheduler as a multi-objective, multi-modal scheduler that maximizes system throughput while minimizing energy consumption or financial cost. We evaluate OSCAR via implementation on Linux, as well as via simulation, and compare our results to the current optimal achievable throughput, cost, and energy consumption. Our evaluation shows that, in the throughput maximization mode, we provide up to 150% enhancement in throughput compared to current operating systems, without any changes to legacy servers. Moreover, this performance gain further increases with the availability of connection resume-supporting, or OSCAR-enabled servers, reaching the maximum achievable upper-bound throughput.
---
paper_title: INTELiCON: Intelligent Connectivity Framework for the Simultaneous Use of Multiple Interfaces

paper_content:

Widespread deployment of Wi-Fi together with 3G upgrades to cellular networks is rapidly creating areas where multiple wireless IP technologies are accessible. WiMAX will further contribute to this phenomenon. The ability to use diverse access technologies simultaneously creates opportunities to improve application service quality and reliability. In this paper, we present an intelligent connectivity framework (INTELiCON) that allows devices to exploit access diversity in new ways. INTELiCON provides a modular, flexible platform for discovering, selecting, executing and evaluating the most appropriate connectivity strategies. The framework executes connectivity strategies and evaluates their effectiveness while maintaining transparency to the application layer. Furthermore INTELiCON can also dynamically implement new strategies to meet variations in network conditions or application requirements. We present the architectural characteristics of the INTELiCON framework with details of a prototype implementation and show how the framework exploits access diversity to support high-quality streaming video despite limited resources and unreliable links.
---
paper_title: Improving TCP performance over an on-board multi-homed network

paper_content:

Previously, a multi-homed NEMO architecture has been proposed to improve the reliability and aggregate the bandwidth of MR by simultaneously using multiple wireless links. In this work, we propose a novel protocol called ETOM (Enhancements for TCP On a Multi-homed mobile router) to improve the performance of sending a single TCP connection over multiple wireless links on a MR. ETOM consists of three components. First, we use a reordering buffer to eliminate unnecessary retransmission caused by out-of-order packets. Second, we develop a Multi-homed Split Connection mechanism to enable the TCP connection to quickly adapt to the conditions of multiple links when packet loss occurs. Finally, a Scheduled Window-based Transmission Control algorithm is proposed to mitigate the negative effects of out-of-order packets in the case of using heterogeneous links in a multi-homed environment. We evaluate the performance of ETOM by comparing it with the Concurrent Multi-path Transfer SCTP (CMT-SCTP). ETOM resolves several performance issues that could hinder the development and practical application of multi-homed mobile router technology.
---
paper_title: An architecture for packet-striping protocols

paper_content:

Link-striping algorithms are often used to overcome transmission bottlenecks in computer networks. Traditional striping algorithms suffer from two major disadvantages. They provide inadequate load sharing in the presence of variable-length packets, and may result in non-FIFO delivery of data. We describe a new family of link-striping algorithms that solves both problems. Our scheme applies to any layer that can provide multiple FIFO channels. We deal with variable-sized packets by showing how fair-queuing algorithms can be transformed into load-sharing algorithms. Our transformation results in practical load-sharing protocols, and shows a theoretical connection between two seemingly different problems. The same transformation can be applied to obtain load-sharing protocols for links with different capacities. We deal with the FIFO requirement for two separate cases. If a sequence number can be added to each packet, we show how to speed up packet processing by letting the receiver simulate the sender algorithm. If no header can be added, we show how to provide quasi FIFO delivery. Quasi FIFO is FIFO except during occasional periods of loss of synchronization. We argue that quasi FIFO is adequate for most applications. We also describe a simple technique for speedy restoration of synchronization in the event of loss. We develop an architectural framework for transparently embedding our protocol at the network level by striping IP packets across multiple physical interfaces. The resulting stripe protocol has been implemented within the NetBSD kernel. Our measurements and simulations show that the protocol offers scalable throughput even when striping is done over dissimilar links, and that the protocol synchronized quickly after packet loss. Measurements show performance improvements over conventional round-robin striping schemes and striping schemes that do not resequence packets. Some aspects of our solution have been implemented in Cisco's router operating system (IOS 11.3) in the context of Multilink PPP striping.
---
paper_title: Improving throughput and reliability in mobile wireless networks via transport layer bandwidth aggregation

paper_content:

Currently, most battlefield mobile communication devices are equipped with multiple wireless interfaces. The main target of the multiple interfaces is to increase the communication reliability between the soldiers in the battlefield and the command center, so that if one of the interfaces fails, the other interfaces can still provide a communication path. In this case each application data stream is limited to use only one communication channel. Due to the limited and variable bandwidth of the wireless channels, as well as their lossy and break-prone nature, the performance of mobile applications can be greatly hurt. In this paper, we present a transport layer solution for aggregating the bandwidth of the available interfaces. Our solution is based on extending Stream Control Transmission Protocol (SCTP). Our choice to extend SCTP for bandwidth aggregation was motivated by its inherent support for multi-homing. The extended SCTP, which we refer to as Load Sharing-SCTP (LS-SCTP), is able to aggregate the bandwidth of all the active transmission paths between the communicating endpoints. In addition, LS-SCTP dynamically adds/drops communication paths to the aggregated paths bundle. To ensure that the aggregate connection will not stall due to the high loss rate or continuous failure of individual paths, LS-SCTP includes path monitoring and packet assignment mechanisms that distribute the packets on the paths according to their current condition. Simulation results demonstrate the effectiveness of our proposed mechanism in providing throughput and reliability to mobile applications under battlefield conditions.
---
paper_title: Multipath TCP algorithms: theory and design

paper_content:

Multi-path TCP (MP-TCP) has the potential to greatly improve application performance by using multiple paths transparently. We propose a fluid model for a large class of MP-TCP algorithms and identify design criteria that guarantee the existence, uniqueness, and stability of system equilibrium. We characterize algorithm parameters for TCP-friendliness and prove an inevitable tradeoff between responsiveness and friendliness. We discuss the implications of these properties on the behavior of existing algorithms and motivate a new design that generalizes existing algorithms. We use ns2 simulations to evaluate the proposed algorithm and illustrate its superior overall performance.
---
paper_title: E2EMPT: A transport layer architecture for end-to-end multipath transfer

paper_content:

With the evolving of the network technology, the number of terminal equipping with multiple network interfaces keeps increasing because of the deploying of various access methods and the price descending of access devices. However, the terminals can not make full use of multiple interfaces concurrently in conversional network. In this paper, we motivate the advantages of simultaneously using multiple interfaces and present a transport layer architecture, E2EMPT, which supports end-to-end multipath transfer. E2EMPT (i) exploits path diversity and distributes data adaptively following characters of the end-toend paths, (ii) reduces the effect of reordering when transferring on multiple end-to-end paths, (iii) implements smart path management policies to select appropriate end-to-end paths. Our evaluation using simulations suggests that E2EMPT aggregates bandwidth of the terminal interfaces efficiently, and meanwhile improves the security and reliability of data transfer.
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paper_title: The Design of Mobile Concurrent Multipath Transfer in Multihomed Wireless Mobile Networks

paper_content:

As more and more devices are equipped with multiple network interfaces, the multihomed technology is becoming an important technology that can provide more reliable connection against the network failure and higher data transmission rate. Concurrent Multipath Transfer (CMT), which is based on SCTP, is devised for multihomed networks. CMT can transmit data over all paths to maximize the data transmission speed. One of the main concerns of CMT is the receiver buffer blocking issue, especially in multihomed wireless mobile networks. Receiver buffer blocking is mainly caused by lost data. In this paper, we propose mobile CMT (mCMT) over wireless networks to deal with the receiver buffer blocking caused by error loss and handoff loss. mCMT has the features of (i) path-oriented multistreaming, (ii) MIH-assisted handoff mechanism, in which MIH denotes Media Independent Handover and (iii) association resume. Path-oriented multistreaming can reduce the receiver buffer blocking caused by error loss. MIH-assisted a handoff can reduce the amount of packet loss during a handoff, which may lead to receiver buffer blocking. Moreover, mCMT introduces the concept of association resume to recover the disconnected association. Simulation results show that mCMT can reduce the effect of the receiver buffer blocking effectively for devices that have smaller buffer size.
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paper_title: LS-SCTP: a bandwidth aggregation technique for stream control transmission protocol

paper_content:

Stream Control Transmission Protocol (SCTP) specifications utilize the multiple paths capabilities between the sender and receiver for retransmission of lost data chunks and as a backup in case of primary path failure. Under normal conditions, all data chunks are sent on the primary path chosen by the SCTP user during the transport connection initiation. In this paper, we address in detail various aspects related to extending and engineering SCTP in order to utilize the available paths for simultaneous transmission of data chunks, while maintaining the SCTP congestion control on each path so as to ensure fair integration with other traffic in the network. The extended SCTP, referred to as Load-Sharing SCTP (LS-SCTP), is able to aggregate the bandwidth of all the active transmission paths between the communicating endpoints. LS-SCTP monitors the paths, and accordingly it chooses the paths that are suitable for load sharing. LS-SCTP retransmission mechanism accelerates the delivery of missing data to the receiver in order to prevent stalling the transport connection while waiting for missing data chunks. Simulation results show that LS-SCTP is extremely beneficial for networks with limited bandwidth, high loss rate and failure prone links.
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paper_title: QoS-oriented MPTCP Extensions for Multimedia Multi-homed Systems

paper_content:

The increasing number of interfaces using different access technologies in modern devices gives opportunities for enhancing the Quality of Service (QoS) delivered to multimedia and interactive data transfers involved in distributed applications. In the current Internet, the presence of "middleboxes" such as Network Address Translators (NAT) or firewalls hardly lets applications use any Transport protocol but the well-known Transmission Control Protocol (TCP). Currently under standardization at the IETF, the new Multipath-TCP (MPTCP) protocol uses several TCP flows to make use of the multiple interfaces available on the end terminals, thus improving both network availability and QoS, still being capable to cross over middle boxes. Although originally being fully reliable and fully ordered, its two sub-layers architecture gives opportunity to use QoS techniques over fully reliable paths. This paper studies the QoS benefits induced by the implementation of the "partial reliability" concept in MPTCP for interactive video applications. Two different mechanisms are experimented with the aim to enhance global quality of video transmission over paths close to 3G networks characteristics. The Internet Engineering Task Force (IETF) MPTCP working group's ns-2 implementation is used for the experimentations. The Evalvid toolkit over ns-2 is used to measure the QoS benefits expressed in terms of Peak Signal to Noise Ratio (PSNR).
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paper_title: cmpSCTP: An Extension of SCTP to Support Concurrent Multi-Path Transfer

paper_content:

This paper introduced cmpSCTP, a transport layer solution for concurrent multi-path transfer that modifies the standard Stream Control Transmission Protocol (SCTP). The cmpSCTP aims at exploiting SCTP's multi-homing capability by selecting several best paths among multiple available network interfaces to improve data transfer rate to the same multi-homed device. Through the use of path monitoring and packet allotment techniques, cmpSCTP tries to transmit given amount of packets at corresponding path as its ability. At the same time, cmpSCTP updates the transmission strategy based on the real-time information of all of paths. Using cmpSCTP's flexible path management capability, we may switch the flow between multiple paths automatically to realize seamless path handover. Extensive simulations under different scenarios using OPNET verified that cmpSCTP can effectively enhance transmission efficiency and highlighted the superiority of cmpSCTP against the other SCTP's extension implementations under performance indexes such as throughput, handover latency, packet delay, and packet loss.
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paper_title: A Concurrent Multipath TCP and Its Markov Model

paper_content:

Concurrent Multipath Transport (CMT) has been of increasing interest recently for aggregating bandwidth, balancing load, and increasing reliability. In this paper we propose a concurrent multipath Transport Control Protocol (cmpTCP), which is an extension of TCP New Reno and Steam Control Transmission Protocol (SCTP). The proposed cmpTCP has been implemented by altering and extending library-based open-source for SCTP. The proposed cmpTCP manages transport control parameters of all paths simultaneously; a scheduler concurrently dispatches packets over all the paths from a common transmission queue. However, one virtual retransmission queue is maintained for each path, and the receiver sends acknowledgment for a packet on the same path on which the packet is received. A Markov model for estimation of expected window size of each path has been proposed. Next, the proposed model has been utilized to derive an expression for computing average data transmission rate when the proposed cmpTCP is used. To validate performance of the proposed model, two host computers were connected through two independent network emulators. Each network emulator runs on a separate computer, and the network parameters are adjusted independently. We used our cmpTCP for transferring files from one host to the other. Comparison of experimental results with model predicted results shows excellent agreement.
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paper_title: MPSCTP: A multipath variant of SCTP and its performance comparison with other multipath protocols

paper_content:

Multipath protocols have great potential to improve error resilience and utilization of scarce network resources. In 2000, IETF introduced Stream Control Transmission Protocol (SCTP) for multihomed transport. Concurrent Multipath Transfer (CMT) and Multipath SCTP (MPSCTP) were proposed as extensions of SCTP to support concurrent usage of available paths. Our original MPSCTP proposal assumes that all the paths between the source and the destination are disjoint and there is no acknowledgement loss in the reverse direction. In this paper we propose a generalized version of the MPSCTP protocol where these assumptions are relaxed. We also present a comparative study of the performance of MPSCTP with CMT and MPTCP, a multipath variant of TCP, in different network scenarios using ns-2 based simulations.
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paper_title: A Multipath Cubic TCP Congestion Control with Multipath Fast Recovery over High Bandwidth-Delay Product Networks

paper_content:

Cubic TCP, one of transport protocols designed for high bandwidth-delay product (BDP) networks, has successfully been deployed in the Internet. Multi-homed computers with multiple interfaces to access the Internet via high speed links will become more popular. In this work, we introduce an extended version of Cubic TCP for multiple paths, called MPCubic. The extension process is approached from an analysis model of Cubic by using coordinated congestion control between paths. MPCubic can spread its traffic across paths in load-balancing manner, while preserving fair sharing with regular TCP, Cubic, and MPTCP at common bottlenecks. Moreover, to improve resilience to link failure, we propose a multipath fast recovery algorithm. The algorithm can significantly reduce the recovery time of data rate after restoration of failed links. These techniques can be useful for resilient high-bandwidth applications (for example, tele-health conference) in disaster-affected areas. Our simulation results show that MPCubic can achieve stability, throughput improvement, fairness, load-balancing, and quick data rate recovery from link failure under a variety of network conditions. key words: multipath congestion control, Cubic TCP for multiple paths, load-balancing, resource pooling, fairness, resilience, disaster
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paper_title: WiMP-SCTP: Multi-Path Transmission Using Stream Control Transmission Protocol (SCTP) in Wireless Networks

paper_content:

In this paper, WiMP-SCTP, which allows a host to improve its transmission goodput in wireless networks using multi-path transmission of stream control transmission protocol, is proposed. Along with a transmission mode switching scheme, two transmission modes of WiMP-SCTP, i.e., the "Data-duplicating Mode" and the "Data-striping Mode", are designed to enhance transmission goodputs for different wireless link status. The issue of path selection scenarios are investigated and the possible solution for the path selection is also discussed in this paper.
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paper_title: MPSCTP: A Simple and Efficient Multipath Algorithm for SCTP

paper_content:

A simple multipath algorithm is proposed to augment Stream Control Transmission Protocol (SCTP) so that multiple available paths may be used concurrently. This requires an additional sequence number in the SCTP header for packets of each path and additional algorithms to handle the reordering that may naturally arise due to flow division over multiple paths. Performance of the proposed protocol has been studied using ns2 based simulation. The results indicate that our algorithm reduces the transmission delay and improves the throughput of the network.
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paper_title: Multipath Binomial Congestion Control Algorithms

paper_content:

Nowadays portable devices with multiple wireless interfaces and using multimedia services are becoming more popular on the Internet. This paper describes a family of multipath binomial congestion control algorithms for audio/video streaming, where a low variant of transmission rate is important. We extend the fluid model of binomial algorithms for single-path transmission to support the concurrent transmission of packets across multiple paths. We focus on the extension of two particular algorithms, SQRT and IIAD, for multiple paths, called MPSQRT and MPIIAD, respectively. Additionally, we apply the design technique (using the multipath fluid model) for multipath TCP (MPTCP) into the extension of SQRT and IIAD, called fbMPSQRT and fbMPIIAD, respectively. Both two approaches ensure that multipath binomial congestion control algorithms achieve load-balancing, throughput improvement, and fairness to single-path binomial algorithms at shared bottlenecks. Through the simulations and comparison with the uncoordinated protocols MPSQRT/MPIIAD, fbMPSQRT/fbMPIIAD and MPTCP, we find that our extended multipath transport protocols can preserve lower latency and transmission rate variance than MPTCP, fairly share with single-path SQRT/IIAD, MPTCP and TCP, and also can achieve throughput improvements and load-balancing equivalent to those of MPTCP under various scenarios and network conditions. key words: multipath binomial congestion control, multimedia streaming, fairness, load-balancing
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paper_title: Design, implementation and evaluation of congestion control for multipath TCP

paper_content:

Multipath TCP, as proposed by the IETF working group mptcp, allows a single data stream to be split across multiple paths. This has obvious benefits for reliability, and it can also lead to more efficient use of networked resources. We describe the design of a multipath congestion control algorithm, we implement it in Linux, and we evaluate it for multihomed servers, data centers and mobile clients. We show that some 'obvious' solutions for multipath congestion control can be harmful, but that our algorithm improves throughput and fairness compared to single-path TCP. Our algorithmis a drop-in replacement for TCP, and we believe it is safe to deploy.
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paper_title: Multi-Path Load Balancing in Transport Layer

paper_content:

In this paper, we propose an extension to current TCP protocol named concurrent TCP (cTCP), which can improve throughput of connections through balancing traffic load on multiple end-to-end paths. We keep the single-sliding-window architecture of TCP untouched for compatibility reasons. The two core components of the design are a packet scheduling switch that balances load among paths, and a duplicated acknowledgement classifier that handles packet reordering. We implemented our protocol in FreeBSD kernel and compared the performance of cTCP with theoretical results. Experiment outcomes show that throughputs of our protocol are close to the ideal values.
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paper_title: Feasibility considerations of multipath TCP in dealing with big data application

paper_content:

In this paper we present an idea to handle big data in a better way. We consider Multipath TCP (MPTCP) to use all available paths simultaneously. MPTCP is a tailored form of TCP which aspire to improve throughput by sharing available resources smartly and fairly. The key concentration of this paper is to analyze the benefit of MPTCP over single path TCP for bandwidth and time sensitive applications as well as big data application. Our simulation shows that MPTCP can higher goodput by bandwidth aggregation, Couple Congestion Control(CCC) provide better throughput without being unfair to other legacy TCP flows and also portray that large receive buffer causes performance enhancement for relatively large RTT link. As a result, MPTCP can be a enormous addition in contrast with single path TCP in dealing with big data application.
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paper_title: A Network Layer Approach to Enable TCP over Multiple Interfaces

paper_content:

The mobile Internet is set to become ubiquitous with the deployment of various wireless technologies. When heterogeneous wireless networks overlap in coverage, a mobile terminal can potentially use multiple wireless interfaces simultaneously. In this paper, we motivate the advantages of simultaneous use of multiple interfaces and present a network layer architecture that supports diverse multi-access services. Our main focus is on one such service provided by the architecture: Bandwidth Aggregation (BAG), specifically for TCP applications.While aggregating bandwidth across multiple interfaces can improve raw throughput, it introduces challenges in the form of packet reordering for TCP applications. When packets are reordered, TCP misinterprets the duplicate ACKS received as indicative of packet loss and invokes congestion control. This can significantly lower TCP throughput and counter any gains that can be had through bandwidth aggregation. To improve overall performance of TCP, we take a two-pronged approach: (1) We propose a scheduling algorithm that partitions traffic onto the different paths (corresponding to each interface) such that reordering is minimized. The algorithm estimates available bandwidth and thereby minimizes reordering by sending packet pairs on the path that introduces the least amount of delay. (2) A buffer management policy is introduced at the client to hide any residual reordering from TCP. We show through simulations that our network-layer approach can achieve good bandwidth aggregation under a variety of network conditions.
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paper_title: Improved access point selection

paper_content:

This paper presents Virgil, an automatic access point discovery and selection system. Unlike existing systems that select access points based entirely on received signal strength, Virgil scans for all available APs at a location, quickly associates to each, and runs a battery of tests to estimate the quality of each AP's connection to the Internet. Virgil also probes for blocked or redirected ports, to guide AP selection in favor of preserving application services that are currently in use. Results of our evaluation across five neighborhoods in three cities show Virgil finds a usable connection from 22% to 100% more often than selecting based on signal strength alone. By caching AP test results, Virgil both improves performance and success rate. Our overhead is acceptable and is shown to be faster than manually selecting an AP with Windows XP.
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paper_title: G-DBAS: A green and deployable bandwidth aggregation system

paper_content:

The widespread deployment of varying networking technologies, coupled with the exponential increase in end-user data demand, have all led to the proliferation of multi-homed or multi-interface enabled devices. To date, these interfaces are mainly utilized one at a time based on network availability, cost, and user-choice. Researchers have recently focused on leveraging these interfaces simultaneously by proposing solutions to aggregate their bandwidths in order to ultimately increase throughput and satisfy the end-user's growing demand on data. These solutions, however, have faced a steep deployment barrier due to various system design choices and heavy demand on energy. In this paper, we propose a novel Green and Deployable Bandwidth Aggregation System (G-DBAS) for multiple interface enabled devices. G-DBAS addresses a set of challenges including automatically estimating the characteristics of applications and scheduling various connections to different interfaces along with meeting different energy consumption goals set by users. We fully implement G-DBAS on the Windows OS and evaluate various scheduling strategies that we propose. Our implementation and simulation results show that G-DBAS can achieve the user energy-throughput goals while operating as an out-of-the-box standard Windows executable, highlighting its deployability and ease of use.
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paper_title: Design and implementation of a socket-level bandwidth aggregation mechanism for wireless networks

paper_content:

This paper proposes a mechanism to aggregate bandwidth of multiple network interfaces on a computer. Recently one single computer entails multiple different wireless network interfaces, such as IEEE 802.11a/b/g/n, Bluetooth, WiMAX, and so on. They can be combined, and we can aquire broad bandwidth. We designed and developed a Socket-level Bandwidth Aggregation Mechanism (SBAM). SBAM can aggregate multiple interfaces on a computer to offer broad bandwidth. In addition, implementation in socket layer causes easy deployment and adaptation to existing environment. We evaluated SBAM under actual wireless network environments. SBAM offers broad bandwidth by utilizing various wireless devices on a computer while it avoids modification to existing environment.
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paper_title: Cross-layer FPS: A SCTP-based cross-layer data scheduling approach

paper_content:

In heterogeneous wireless networks, multi-interfaced mobile terminals may be connected to links with rapidly varying MAC and physical characteristics. On the other hand, current deployment of communication protocols rely on the information available at associated layer only. In order to improve transport layer performance for multi-homed mobile terminals, we propose a cross-layer approach to schedule data over multiple available paths. Our data-striping approach strengthens the cooperation between higher and lower layers and enables transport layer mechanism to exploit information provided by MAC layer. We compare our approach with existing techniques and prove that our cross-layer system improves multipath performance over single-layer multipath systems.
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paper_title: MOTA: engineering an operator agnostic mobile service

paper_content:

There are two emerging trends in the mobile data world. First, mobile data is exploding at a rapid rate with analysts predicting 25-50X growth by the year 2015. The second trend is that users are demanding greater degree of flexibility in selecting their operators at fine timescales. Across Asia, dual-SIM phones have become popular, while Apple is rumored to be designing a Universal SIM that will allow iPhone users to toggle between different operators. This latter trend points towards an impending disruption in wireless service models which could also be the need of the hour from the spectrum shortage perspective. This points towards a new service model where users can choose an operator based on application needs. However, if users make this choice greedily without network assistance, it can exacerbate spectrum scarcity and degrade user experience. In this work, we consider user devices with multiple network interfaces (3G, LTE etc.) that can be simultaneously active and each running multiple applications. We propose the MOTA service model to enable users to associate each interface with the operator of choice at fine time scales. Under the MOTA service model, through concise signalling information, operators provide information about their own network, so that each user can (i) choose a suitable operator for each interface, and (ii) choose an interface for each active application. We make the following contributions in this paper. First, we propose concise network signalling that assists users to make informed choices even under mobility. Second, we develop user-choice algorithms that maximize a suitable notion of user satisfaction while using spectrum resources efficiently. Third, we perform extensive evaluation over actual base station deployment in a city coupled with real signal propagation maps. Our results with two operators show that, MOTA service model provides capacity gain in the range 2.5-4X over the current existing service model. Finally, we argue that our solution is practically implementable by combining appropriate IEEE standards and IETF proposals.
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paper_title: Transport level mechanisms for bandwidth aggregation on mobile hosts

paper_content:

Present mobile computing does not support the simultaneous use of multiple heterogeneous network interfaces for a single transport layer connection. We describe a solution for channel aggregation at the transport layer, which provides increased bandwidth to mobile nodes. We present R-MTP (reliable multiplexing transport protocol), a rate-based reliable transport protocol capable of multiplexing data from a single application data stream across multiple network interfaces. Due to the lossy nature of wireless links in mobile environments, R-MTP tracks packet interarrival time for discrimination between congestion-based and transmission-based losses as well as better bandwidth estimation. The challenges to such a reliable protocol lie in the coordination of packets across streams with varying channel characteristics. Our experimental results validate R-MTP's bandwidth estimation and loss characterization techniques. Successful bandwidth aggregation is demonstrated in ideal and lossy environments.
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paper_title: A network-layer proxy for bandwidth aggregation and reduction of IP packet reordering

paper_content:

With today's widespread deployment of wireless technologies, it is often the case that a single communication device can select from a variety of access networks. At the same time, there is an ongoing trend towards integration of multiple network interfaces into end-hosts, such as cell phones with HSDPA, Bluetooth and WLAN. By using multiple Internet connections concurrently, network applications can benefit from aggregated bandwidth and increased fault tolerance. However, the heterogeneity of wireless environments introduce challenges with respect to implementation, deployment, and protocol compatibility. Variable link characteristics cause reordering when sending IP packets of the same flow over multiple paths. This paper introduces a multilink proxy that is able to transparently stripe traffic destined for multihomed clients. Operating on the network layer, the proxy uses path monitoring statistics to adapt to changes in throughput and latency. Experimental results obtained from a proof-of-concept implementation verify that our approach is able to fully aggregate the throughput of heterogeneous downlink streams, even if the path characteristics change over time. In addition, our novel method of equalizing delays by buffering packets on the proxy significantly reduces IP packet reordering and the buffer requirements of clients.
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paper_title: OPERETTA: An optimal energy efficient bandwidth aggregation system

paper_content:

The widespread deployment of varying networking technologies, coupled with the exponential increase in end-user data demand, have led to the proliferation of multi-homed or multi-interface enabled devices. To date, these interfaces are mainly utilized one at a time based on network availability, cost, and user-choice. While researchers have focused on simultaneously leveraging these interfaces by aggregating their bandwidths, these solutions however, have faced a steep deployment barrier. In this paper, we propose a novel optimal, energy-efficient, and deployable bandwidth aggregation system (OPERETTA) for multiple interface enabled devices. OPERETTA satisfies three goals: achieving a user defined throughput level with optimal energy consumption over multiple interfaces, deployability without changes to current legacy servers, and leveraging incremental deployment to achieve increased performance gains. We present the OPERETTA architecture and formulate the optimal scheduling problem as a mixed integer programming problem yielding an efficient solution. We evaluate OPERETTA via implementation on the the Windows OS, and further verify our results with simulations on NS2. Our evaluation shows the tradeoffs between the energy and throughput goals. Furthermore, with no modifications to current legacy servers, OPERETTA achieves throughput gains up to 150% compared to current operating systems with the same energy consumption. In addition, with as few as 25% of the servers becoming OPERETTA enabled, OPERETTA performance reaches the throughput upper bound, highlighting its incremental deployment and performance gains.
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paper_title: A Data-Scheduling Mechanism for Multi-Homed Mobile Terminals with Disparate Link Latencies

paper_content:

A mobile terminal equipped with multiple network interfaces can often be found under coverage of multiple access networks. Multihoming enables mobile terminals to communicate simultaneously through multiple interfaces. Connection-oriented transport layer mechanisms ensure reliable, in-order delivery of data, however parallel data transfers in multihoming face problems due to out-of-order reception of data which causes fast-retransmissions and limit the communication throughput. In this paper, we propose a transport layer based mechanism which stripes one flow''s data across multiple disjoint paths efficiently, reducing possible occurrence of out-of-order data. Our mechanism estimates arrival times of data packets to be sent through available paths in an association, and decides which packets are to be sent through each path. We compared our mechanism with a relatively closer approach called Westwood SCTP. We illustrate with the help of simulation results that our mechanism proves to improve multipath communication.
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paper_title: DNIS: a middleware for dynamic multiple network interfaces scheduling

paper_content:

Wireless Intelligent Networks Center, Nile University, Smart Village, Egypt Many of today's mobile devices are equipped with multiple network interfaces that can be used to connect to the Internet, including Ethernet, WiFi, 3G, and Bluetooth. However, current operating systems, such as Windows and Linux, typically choose only one of the available network interfaces and assign all the traffic to it, even if more than one is connected to the Internet. This results in an obvious under utilization of the available bandwidth. Different bandwidth aggregation techniques suggested altering different layers of the TCP/IP stack which requires applying modifications on the client's stack and/or the cloud, which cannot be widely deployed easily. In this work, we present DNIS, a networking middleware that achieves bandwidth aggregation using per-TCP connection scheduling on different interfaces in a way that is transparent to both the user and the applications. DNIS is composed of two main components: (1) a parameter estimator that estimates the applications' characteristics and requirements as well as interfaces' properties; (2) a scheduler that uses the estimated parameters to assign different TCP connections to network interfaces. We present an implementation for DNIS for the Windows OS and show its performance for different scheduling algorithms. Our initial results show significant enhancement of the overall device's throughput, up to 54%, increasing resource utilization and enhancing the user's experience.
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paper_title: A User-level Socket Layer over Multiple Physical Network Interfaces

paper_content:

In this paper, we describe the design and implementation of an UDP-based socket that utilizes multiple network interface units connected through one or more networks. The socket is a middleware layer that provides abstract network APIs to hide low-level technical details from users. Parallel message fragmentation and reconstruction techniques and a reliable UDP-based protocol are introduced. The proposed socket layer transparently provides an expandable high bandwidth solution, fault tolerance, and load balancing for transmitting large messages over multiple networks. A prototype socket based on this model, called MuniSocket (Multiple Network Interface Socket), has been implemented and evaluated.
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paper_title: DBAS: A Deployable Bandwidth Aggregation System

paper_content:

The explosive increase in data demand coupled with the rapid deployment of various wireless access technologies have led to the increase of number of multi-homed or multi-interface enabled devices. Fully exploiting these interfaces has motivated researchers to propose numerous solutions that aggregate their available bandwidths to increase overall throughput and satisfy the end-user's growing data demand. These solutions, however, have faced a steep deployment barrier that we attempt to overcome in this paper. We propose a Deployable Bandwidth Aggregation System (DBAS) for multi- interface enabled devices. Our system does not introduce any intermediate hardware, modify current operating systems, modify socket implementations, nor require changes to current applications or legacy servers. The DBAS architecture is designed to automatically estimate the characteristics of applications and dynamically schedule various connections or packets to different interfaces. Since our main focus is deployability, we fully implement DBAS on the Windows operating system and evaluate various modes of operation. Our implementation and simulation results show that DBAS achieves up to more than double the throughput gains compared to current operating systems, while operating as an out-of-the- box standard Windows executable, highlighting its deployability.
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paper_title: GreenBag: Energy-Efficient Bandwidth Aggregation for Real-Time Streaming in Heterogeneous Mobile Wireless Networks

paper_content:

Modern mobile devices are equipped with multiple network interfaces, including 3G/LTE and WiFi. Bandwidth aggregation over LTE and WiFi links offers an attractive opportunity of supporting bandwidth-intensive services, such as high-quality video streaming, on mobile devices. However, achieving effective bandwidth aggregation in mobile environments raises several challenges related to deployment, link heterogeneity, network fluctuation, and energy consumption. We present GreenBag, an energy-efficient bandwidth aggregation middleware that supports real-time data-streaming services over asymmetric wireless links, requiring no modifications to the existing Internet infrastructure and servers. GreenBag employs several techniques, including medium load balancing, efficient segment management, and energy-aware mode control, to resolve such challenges. We implement a prototype of GreenBag on Android-based mobile devices which hosts, to the best knowledge of the authors, the first LTE-enabled bandwidth aggregation prototype for energy-efficient real-time video streaming. Our experiment results in both emulated and real-world environments show that GreenBag not only achieves good bandwidth aggregation to provide QoS in bandwidth-scarce environments but also efficiently saves energy on mobile devices. Moreover, energy-aware GreenBag can minimize video interruption while consuming 14-25% less energy than the non-energy-aware counterpart in real-world experiments.
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paper_title: Improved data distribution for multipath TCP communication

paper_content:

Multi-homed environments are increasingly common, especially for mobile users. To efficiently utilize multiple access lines for single file transfer, multipath TCP communication methods have been proposed. A multipath TCP enables simultaneous distributed data transfer between two end-points on multiple TCP connections. However, these methods cannot fully utilize the available bandwidth of multiple paths because they do not properly consider the end-to-end delay of packet transmission, so out-of-order data arrival at a receiver causes a bottleneck in data sort operations. This problem is more severe in environments where the quality of each path is different or unstable, such as in wireless environments. To solve this problem, we propose a multipath TCP communication method that includes a data distribution method to enable in-order delivery at a receiver. We call this arrival-time matching load-balancing (ATLB). ATLB continuously calculates the delay of each path, including the TCP queuing delay at a sender and the network delay, and then sends a data segment through the TCP connection with the lowest end-to-end delay. Simulation results show that ATLB improves end-to-end throughput, especially in heterogeneous environments where the quality of paths differs. For example, ATLB enabled twice the throughput with the conventional multipath TCP. We also report performance evaluation results from our ATLB test bed system in a wireless network environment. Our ATLB test bed system was able to fully utilize the aggregate available bandwidth of unstable multiple wireless links.
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paper_title: Intentional networking: opportunistic exploitation of mobile network diversity

paper_content:

Mobile devices face a diverse and dynamic set of networking options. Using those options to the fullest requires knowledge of application intent. This paper describes Intentional Networking, a simple but powerful mechanism for handling network diversity. Applications supply a declarative label for network transmissions, and the system matches transmissions to the most appropriate network. The system may also defer and re-order opportunistic transmissions subject to application-supplied mutual exclusion and ordering constraints. We have modified three applications to use Intentional Networking: BlueFS, a distributed file system for pervasive computing, Mozilla's Thunderbird e-mail client, and a vehicular participatory sensing application. We evaluated the performance of these applications using measurements obtained by driving a vehicle through WiFi and cellular 3G network coverage. Compared to an idealized solution that makes optimal use of all aggregated available networks but that lacks knowledge of application intent, Intentional Networking improves the latency of interactive messages from 48% to 13x, while adding no more than 7% throughput overhead.
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paper_title: A novel mechanism for data streaming across multiple IP links for improving throughput and reliability in mobile environments

paper_content:

With ubiquitous computing and network access, multiple network conduits are becoming available to mobile as well as static hosts. Selection of the preferred mode of data transfer is a dynamic optimization problem depending on the type of application, its bandwidth/latency/jitter requirements, current network status, cost, power consumption, battery life, and so on. Furthermore, since wireless bandwidth is likely to remain a scarce resource, we foresee scenarios wherein mobile hosts require simultaneous data transfer across multiple IP interfaces to obtain higher overall bandwidth. We present a brief overview of related work identifying schemes that might be applicable to the problem, along with their feasibility, and pros and cons. We then propose a new mechanism to aggregate the bandwidth of multiple IP links by splitting a data flow across multiple network interfaces at the IP level. Our method is transparent to transport (TCP/UDP) and higher layers. We have analyzed the performance characteristics of the aggregation scheme and demonstrated significant gain when the links being aggregated have similar bandwidth and latency. The use of multiple interfaces also enhances reliability. Our analysis identifies the conditions under which the proposed scheme, or any other scheme that stripes a single TCP connection across multiple IP links, can be used to enhance throughput. Several interesting directions for future work have also been identified.
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paper_title: OSCAR: A Collaborative Bandwidth Aggregation System

paper_content:

The exponential increase in mobile data demand, coupled with growing user expectation to be connected in all places at all times, have introduced novel challenges for researchers to address. Fortunately, the wide spread deployment of various network technologies and the increased adoption of multi-interface enabled devices have enabled researchers to develop solutions for those challenges. Such solutions aim to exploit available interfaces on such devices in both solitary and collaborative forms. These solutions, however, have faced a steep deployment barrier. ::: In this paper, we present OSCAR, a multi-objective, incentive-based, collaborative, and deployable bandwidth aggregation system. We present the OSCAR architecture that does not introduce any intermediate hardware nor require changes to current applications or legacy servers. The OSCAR architecture is designed to automatically estimate the system's context, dynamically schedule various connections and/or packets to different interfaces, be backwards compatible with the current Internet architecture, and provide the user with incentives for collaboration. We also formulate the OSCAR scheduler as a multi-objective, multi-modal scheduler that maximizes system throughput while minimizing energy consumption or financial cost. We evaluate OSCAR via implementation on Linux, as well as via simulation, and compare our results to the current optimal achievable throughput, cost, and energy consumption. Our evaluation shows that, in the throughput maximization mode, we provide up to 150% enhancement in throughput compared to current operating systems, without any changes to legacy servers. Moreover, this performance gain further increases with the availability of connection resume-supporting, or OSCAR-enabled servers, reaching the maximum achievable upper-bound throughput.
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paper_title: Improving TCP performance over an on-board multi-homed network

paper_content:

Previously, a multi-homed NEMO architecture has been proposed to improve the reliability and aggregate the bandwidth of MR by simultaneously using multiple wireless links. In this work, we propose a novel protocol called ETOM (Enhancements for TCP On a Multi-homed mobile router) to improve the performance of sending a single TCP connection over multiple wireless links on a MR. ETOM consists of three components. First, we use a reordering buffer to eliminate unnecessary retransmission caused by out-of-order packets. Second, we develop a Multi-homed Split Connection mechanism to enable the TCP connection to quickly adapt to the conditions of multiple links when packet loss occurs. Finally, a Scheduled Window-based Transmission Control algorithm is proposed to mitigate the negative effects of out-of-order packets in the case of using heterogeneous links in a multi-homed environment. We evaluate the performance of ETOM by comparing it with the Concurrent Multi-path Transfer SCTP (CMT-SCTP). ETOM resolves several performance issues that could hinder the development and practical application of multi-homed mobile router technology.
---
paper_title: Improving throughput and reliability in mobile wireless networks via transport layer bandwidth aggregation

paper_content:

Currently, most battlefield mobile communication devices are equipped with multiple wireless interfaces. The main target of the multiple interfaces is to increase the communication reliability between the soldiers in the battlefield and the command center, so that if one of the interfaces fails, the other interfaces can still provide a communication path. In this case each application data stream is limited to use only one communication channel. Due to the limited and variable bandwidth of the wireless channels, as well as their lossy and break-prone nature, the performance of mobile applications can be greatly hurt. In this paper, we present a transport layer solution for aggregating the bandwidth of the available interfaces. Our solution is based on extending Stream Control Transmission Protocol (SCTP). Our choice to extend SCTP for bandwidth aggregation was motivated by its inherent support for multi-homing. The extended SCTP, which we refer to as Load Sharing-SCTP (LS-SCTP), is able to aggregate the bandwidth of all the active transmission paths between the communicating endpoints. In addition, LS-SCTP dynamically adds/drops communication paths to the aggregated paths bundle. To ensure that the aggregate connection will not stall due to the high loss rate or continuous failure of individual paths, LS-SCTP includes path monitoring and packet assignment mechanisms that distribute the packets on the paths according to their current condition. Simulation results demonstrate the effectiveness of our proposed mechanism in providing throughput and reliability to mobile applications under battlefield conditions.
---
paper_title: Cross-layer FPS: A SCTP-based cross-layer data scheduling approach

paper_content:

In heterogeneous wireless networks, multi-interfaced mobile terminals may be connected to links with rapidly varying MAC and physical characteristics. On the other hand, current deployment of communication protocols rely on the information available at associated layer only. In order to improve transport layer performance for multi-homed mobile terminals, we propose a cross-layer approach to schedule data over multiple available paths. Our data-striping approach strengthens the cooperation between higher and lower layers and enables transport layer mechanism to exploit information provided by MAC layer. We compare our approach with existing techniques and prove that our cross-layer system improves multipath performance over single-layer multipath systems.
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paper_title: A Data-Scheduling Mechanism for Multi-Homed Mobile Terminals with Disparate Link Latencies

paper_content:

A mobile terminal equipped with multiple network interfaces can often be found under coverage of multiple access networks. Multihoming enables mobile terminals to communicate simultaneously through multiple interfaces. Connection-oriented transport layer mechanisms ensure reliable, in-order delivery of data, however parallel data transfers in multihoming face problems due to out-of-order reception of data which causes fast-retransmissions and limit the communication throughput. In this paper, we propose a transport layer based mechanism which stripes one flow''s data across multiple disjoint paths efficiently, reducing possible occurrence of out-of-order data. Our mechanism estimates arrival times of data packets to be sent through available paths in an association, and decides which packets are to be sent through each path. We compared our mechanism with a relatively closer approach called Westwood SCTP. We illustrate with the help of simulation results that our mechanism proves to improve multipath communication.
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paper_title: Intentional networking: opportunistic exploitation of mobile network diversity

paper_content:

Mobile devices face a diverse and dynamic set of networking options. Using those options to the fullest requires knowledge of application intent. This paper describes Intentional Networking, a simple but powerful mechanism for handling network diversity. Applications supply a declarative label for network transmissions, and the system matches transmissions to the most appropriate network. The system may also defer and re-order opportunistic transmissions subject to application-supplied mutual exclusion and ordering constraints. We have modified three applications to use Intentional Networking: BlueFS, a distributed file system for pervasive computing, Mozilla's Thunderbird e-mail client, and a vehicular participatory sensing application. We evaluated the performance of these applications using measurements obtained by driving a vehicle through WiFi and cellular 3G network coverage. Compared to an idealized solution that makes optimal use of all aggregated available networks but that lacks knowledge of application intent, Intentional Networking improves the latency of interactive messages from 48% to 13x, while adding no more than 7% throughput overhead.
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paper_title: LS-SCTP: a bandwidth aggregation technique for stream control transmission protocol

paper_content:

Stream Control Transmission Protocol (SCTP) specifications utilize the multiple paths capabilities between the sender and receiver for retransmission of lost data chunks and as a backup in case of primary path failure. Under normal conditions, all data chunks are sent on the primary path chosen by the SCTP user during the transport connection initiation. In this paper, we address in detail various aspects related to extending and engineering SCTP in order to utilize the available paths for simultaneous transmission of data chunks, while maintaining the SCTP congestion control on each path so as to ensure fair integration with other traffic in the network. The extended SCTP, referred to as Load-Sharing SCTP (LS-SCTP), is able to aggregate the bandwidth of all the active transmission paths between the communicating endpoints. LS-SCTP monitors the paths, and accordingly it chooses the paths that are suitable for load sharing. LS-SCTP retransmission mechanism accelerates the delivery of missing data to the receiver in order to prevent stalling the transport connection while waiting for missing data chunks. Simulation results show that LS-SCTP is extremely beneficial for networks with limited bandwidth, high loss rate and failure prone links.
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paper_title: Westwood SCTP: load balancing over multipaths using bandwidth-aware source scheduling

paper_content:

While it is more and more usual to buy computer equipment with multiple network interfaces, and the proliferation of ISPs for both wired and wireless users provides different solutions to access the network core, upper layers across the protocol spectrum seem unprepared to accept the challenge posed by multiple interfaces and, consequently, by multiple paths between the same source-destination pair. This paper tries to partially answer this challenge by proposing an enhancement of the SCTP protocol that aims at balancing load across multiple connections on disjoint paths in an accurate fashion, through the knowledge of bandwidth estimation on each path. Some results confirm the viability of the approach and invite further research.
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paper_title: cmpSCTP: An Extension of SCTP to Support Concurrent Multi-Path Transfer

paper_content:

This paper introduced cmpSCTP, a transport layer solution for concurrent multi-path transfer that modifies the standard Stream Control Transmission Protocol (SCTP). The cmpSCTP aims at exploiting SCTP's multi-homing capability by selecting several best paths among multiple available network interfaces to improve data transfer rate to the same multi-homed device. Through the use of path monitoring and packet allotment techniques, cmpSCTP tries to transmit given amount of packets at corresponding path as its ability. At the same time, cmpSCTP updates the transmission strategy based on the real-time information of all of paths. Using cmpSCTP's flexible path management capability, we may switch the flow between multiple paths automatically to realize seamless path handover. Extensive simulations under different scenarios using OPNET verified that cmpSCTP can effectively enhance transmission efficiency and highlighted the superiority of cmpSCTP against the other SCTP's extension implementations under performance indexes such as throughput, handover latency, packet delay, and packet loss.
---
paper_title: Bandwidth aggregation with SCTP

paper_content:

We present a number of modifications to the stream control transmission protocol (SCTP) recently adopted by IETF; they allow bandwidth aggregation over the multiple interfaces of a host. We show that it is possible to implement a number of algorithms for bandwidth aggregation, with only a small number of modifications to the basic SCTP. Our simulation results clearly depict the efficiency of our approach in terms of bandwidth utilization. Furthermore, we implement and evaluate a mechanism for identifying bottlenecks that are shared by flows from the same aggregate connection. Our purpose is to show that SCTP is a good candidate for building a practical protocol for bandwidth aggregation that is fair and supportive of TCP.
---
paper_title: MOTA: engineering an operator agnostic mobile service

paper_content:

There are two emerging trends in the mobile data world. First, mobile data is exploding at a rapid rate with analysts predicting 25-50X growth by the year 2015. The second trend is that users are demanding greater degree of flexibility in selecting their operators at fine timescales. Across Asia, dual-SIM phones have become popular, while Apple is rumored to be designing a Universal SIM that will allow iPhone users to toggle between different operators. This latter trend points towards an impending disruption in wireless service models which could also be the need of the hour from the spectrum shortage perspective. This points towards a new service model where users can choose an operator based on application needs. However, if users make this choice greedily without network assistance, it can exacerbate spectrum scarcity and degrade user experience. In this work, we consider user devices with multiple network interfaces (3G, LTE etc.) that can be simultaneously active and each running multiple applications. We propose the MOTA service model to enable users to associate each interface with the operator of choice at fine time scales. Under the MOTA service model, through concise signalling information, operators provide information about their own network, so that each user can (i) choose a suitable operator for each interface, and (ii) choose an interface for each active application. We make the following contributions in this paper. First, we propose concise network signalling that assists users to make informed choices even under mobility. Second, we develop user-choice algorithms that maximize a suitable notion of user satisfaction while using spectrum resources efficiently. Third, we perform extensive evaluation over actual base station deployment in a city coupled with real signal propagation maps. Our results with two operators show that, MOTA service model provides capacity gain in the range 2.5-4X over the current existing service model. Finally, we argue that our solution is practically implementable by combining appropriate IEEE standards and IETF proposals.
---
paper_title: OPERETTA: An optimal energy efficient bandwidth aggregation system

paper_content:

The widespread deployment of varying networking technologies, coupled with the exponential increase in end-user data demand, have led to the proliferation of multi-homed or multi-interface enabled devices. To date, these interfaces are mainly utilized one at a time based on network availability, cost, and user-choice. While researchers have focused on simultaneously leveraging these interfaces by aggregating their bandwidths, these solutions however, have faced a steep deployment barrier. In this paper, we propose a novel optimal, energy-efficient, and deployable bandwidth aggregation system (OPERETTA) for multiple interface enabled devices. OPERETTA satisfies three goals: achieving a user defined throughput level with optimal energy consumption over multiple interfaces, deployability without changes to current legacy servers, and leveraging incremental deployment to achieve increased performance gains. We present the OPERETTA architecture and formulate the optimal scheduling problem as a mixed integer programming problem yielding an efficient solution. We evaluate OPERETTA via implementation on the the Windows OS, and further verify our results with simulations on NS2. Our evaluation shows the tradeoffs between the energy and throughput goals. Furthermore, with no modifications to current legacy servers, OPERETTA achieves throughput gains up to 150% compared to current operating systems with the same energy consumption. In addition, with as few as 25% of the servers becoming OPERETTA enabled, OPERETTA performance reaches the throughput upper bound, highlighting its incremental deployment and performance gains.
---
paper_title: DNIS: a middleware for dynamic multiple network interfaces scheduling

paper_content:

Wireless Intelligent Networks Center, Nile University, Smart Village, Egypt Many of today's mobile devices are equipped with multiple network interfaces that can be used to connect to the Internet, including Ethernet, WiFi, 3G, and Bluetooth. However, current operating systems, such as Windows and Linux, typically choose only one of the available network interfaces and assign all the traffic to it, even if more than one is connected to the Internet. This results in an obvious under utilization of the available bandwidth. Different bandwidth aggregation techniques suggested altering different layers of the TCP/IP stack which requires applying modifications on the client's stack and/or the cloud, which cannot be widely deployed easily. In this work, we present DNIS, a networking middleware that achieves bandwidth aggregation using per-TCP connection scheduling on different interfaces in a way that is transparent to both the user and the applications. DNIS is composed of two main components: (1) a parameter estimator that estimates the applications' characteristics and requirements as well as interfaces' properties; (2) a scheduler that uses the estimated parameters to assign different TCP connections to network interfaces. We present an implementation for DNIS for the Windows OS and show its performance for different scheduling algorithms. Our initial results show significant enhancement of the overall device's throughput, up to 54%, increasing resource utilization and enhancing the user's experience.
---
paper_title: DBAS: A Deployable Bandwidth Aggregation System

paper_content:

The explosive increase in data demand coupled with the rapid deployment of various wireless access technologies have led to the increase of number of multi-homed or multi-interface enabled devices. Fully exploiting these interfaces has motivated researchers to propose numerous solutions that aggregate their available bandwidths to increase overall throughput and satisfy the end-user's growing data demand. These solutions, however, have faced a steep deployment barrier that we attempt to overcome in this paper. We propose a Deployable Bandwidth Aggregation System (DBAS) for multi- interface enabled devices. Our system does not introduce any intermediate hardware, modify current operating systems, modify socket implementations, nor require changes to current applications or legacy servers. The DBAS architecture is designed to automatically estimate the characteristics of applications and dynamically schedule various connections or packets to different interfaces. Since our main focus is deployability, we fully implement DBAS on the Windows operating system and evaluate various modes of operation. Our implementation and simulation results show that DBAS achieves up to more than double the throughput gains compared to current operating systems, while operating as an out-of-the- box standard Windows executable, highlighting its deployability.
---
paper_title: GreenBag: Energy-Efficient Bandwidth Aggregation for Real-Time Streaming in Heterogeneous Mobile Wireless Networks

paper_content:

Modern mobile devices are equipped with multiple network interfaces, including 3G/LTE and WiFi. Bandwidth aggregation over LTE and WiFi links offers an attractive opportunity of supporting bandwidth-intensive services, such as high-quality video streaming, on mobile devices. However, achieving effective bandwidth aggregation in mobile environments raises several challenges related to deployment, link heterogeneity, network fluctuation, and energy consumption. We present GreenBag, an energy-efficient bandwidth aggregation middleware that supports real-time data-streaming services over asymmetric wireless links, requiring no modifications to the existing Internet infrastructure and servers. GreenBag employs several techniques, including medium load balancing, efficient segment management, and energy-aware mode control, to resolve such challenges. We implement a prototype of GreenBag on Android-based mobile devices which hosts, to the best knowledge of the authors, the first LTE-enabled bandwidth aggregation prototype for energy-efficient real-time video streaming. Our experiment results in both emulated and real-world environments show that GreenBag not only achieves good bandwidth aggregation to provide QoS in bandwidth-scarce environments but also efficiently saves energy on mobile devices. Moreover, energy-aware GreenBag can minimize video interruption while consuming 14-25% less energy than the non-energy-aware counterpart in real-world experiments.
---
paper_title: OSCAR: A Collaborative Bandwidth Aggregation System

paper_content:

The exponential increase in mobile data demand, coupled with growing user expectation to be connected in all places at all times, have introduced novel challenges for researchers to address. Fortunately, the wide spread deployment of various network technologies and the increased adoption of multi-interface enabled devices have enabled researchers to develop solutions for those challenges. Such solutions aim to exploit available interfaces on such devices in both solitary and collaborative forms. These solutions, however, have faced a steep deployment barrier. ::: In this paper, we present OSCAR, a multi-objective, incentive-based, collaborative, and deployable bandwidth aggregation system. We present the OSCAR architecture that does not introduce any intermediate hardware nor require changes to current applications or legacy servers. The OSCAR architecture is designed to automatically estimate the system's context, dynamically schedule various connections and/or packets to different interfaces, be backwards compatible with the current Internet architecture, and provide the user with incentives for collaboration. We also formulate the OSCAR scheduler as a multi-objective, multi-modal scheduler that maximizes system throughput while minimizing energy consumption or financial cost. We evaluate OSCAR via implementation on Linux, as well as via simulation, and compare our results to the current optimal achievable throughput, cost, and energy consumption. Our evaluation shows that, in the throughput maximization mode, we provide up to 150% enhancement in throughput compared to current operating systems, without any changes to legacy servers. Moreover, this performance gain further increases with the availability of connection resume-supporting, or OSCAR-enabled servers, reaching the maximum achievable upper-bound throughput.
---
paper_title: G-DBAS: A green and deployable bandwidth aggregation system

paper_content:

The widespread deployment of varying networking technologies, coupled with the exponential increase in end-user data demand, have all led to the proliferation of multi-homed or multi-interface enabled devices. To date, these interfaces are mainly utilized one at a time based on network availability, cost, and user-choice. Researchers have recently focused on leveraging these interfaces simultaneously by proposing solutions to aggregate their bandwidths in order to ultimately increase throughput and satisfy the end-user's growing demand on data. These solutions, however, have faced a steep deployment barrier due to various system design choices and heavy demand on energy. In this paper, we propose a novel Green and Deployable Bandwidth Aggregation System (G-DBAS) for multiple interface enabled devices. G-DBAS addresses a set of challenges including automatically estimating the characteristics of applications and scheduling various connections to different interfaces along with meeting different energy consumption goals set by users. We fully implement G-DBAS on the Windows OS and evaluate various scheduling strategies that we propose. Our implementation and simulation results show that G-DBAS can achieve the user energy-throughput goals while operating as an out-of-the-box standard Windows executable, highlighting its deployability and ease of use.
---
paper_title: MOTA: engineering an operator agnostic mobile service

paper_content:

There are two emerging trends in the mobile data world. First, mobile data is exploding at a rapid rate with analysts predicting 25-50X growth by the year 2015. The second trend is that users are demanding greater degree of flexibility in selecting their operators at fine timescales. Across Asia, dual-SIM phones have become popular, while Apple is rumored to be designing a Universal SIM that will allow iPhone users to toggle between different operators. This latter trend points towards an impending disruption in wireless service models which could also be the need of the hour from the spectrum shortage perspective. This points towards a new service model where users can choose an operator based on application needs. However, if users make this choice greedily without network assistance, it can exacerbate spectrum scarcity and degrade user experience. In this work, we consider user devices with multiple network interfaces (3G, LTE etc.) that can be simultaneously active and each running multiple applications. We propose the MOTA service model to enable users to associate each interface with the operator of choice at fine time scales. Under the MOTA service model, through concise signalling information, operators provide information about their own network, so that each user can (i) choose a suitable operator for each interface, and (ii) choose an interface for each active application. We make the following contributions in this paper. First, we propose concise network signalling that assists users to make informed choices even under mobility. Second, we develop user-choice algorithms that maximize a suitable notion of user satisfaction while using spectrum resources efficiently. Third, we perform extensive evaluation over actual base station deployment in a city coupled with real signal propagation maps. Our results with two operators show that, MOTA service model provides capacity gain in the range 2.5-4X over the current existing service model. Finally, we argue that our solution is practically implementable by combining appropriate IEEE standards and IETF proposals.
---
paper_title: OPERETTA: An optimal energy efficient bandwidth aggregation system

paper_content:

The widespread deployment of varying networking technologies, coupled with the exponential increase in end-user data demand, have led to the proliferation of multi-homed or multi-interface enabled devices. To date, these interfaces are mainly utilized one at a time based on network availability, cost, and user-choice. While researchers have focused on simultaneously leveraging these interfaces by aggregating their bandwidths, these solutions however, have faced a steep deployment barrier. In this paper, we propose a novel optimal, energy-efficient, and deployable bandwidth aggregation system (OPERETTA) for multiple interface enabled devices. OPERETTA satisfies three goals: achieving a user defined throughput level with optimal energy consumption over multiple interfaces, deployability without changes to current legacy servers, and leveraging incremental deployment to achieve increased performance gains. We present the OPERETTA architecture and formulate the optimal scheduling problem as a mixed integer programming problem yielding an efficient solution. We evaluate OPERETTA via implementation on the the Windows OS, and further verify our results with simulations on NS2. Our evaluation shows the tradeoffs between the energy and throughput goals. Furthermore, with no modifications to current legacy servers, OPERETTA achieves throughput gains up to 150% compared to current operating systems with the same energy consumption. In addition, with as few as 25% of the servers becoming OPERETTA enabled, OPERETTA performance reaches the throughput upper bound, highlighting its incremental deployment and performance gains.
---
paper_title: MAR: a commuter router infrastructure for the mobile Internet

paper_content:

We introduce MAR, a commuter mobile access router infrastructure that exploits wireless diversity (e.g. channel diversity, network diversity, and technology diversity) to provide improved data performance for wireless data users. Our system design stems from the observation that rather than choosing a single wireless service provider (e.g. Sprint, AT&T, BT, Vodafone), a single technology (e.g. GPRS, UMTS, CDMA, 802.11), or a single wireless channel, users can obtain significant benefits by using the multiplicity of choices available. MAR is a wireless multi-homed device that can be placed in moving vehicles (e.g. car, bus, train) to enable high-speed data access. MAR dynamically instantiates new channels based on traffic demand, aggregates the bandwidth and dynamically shifts load from poor quality to better quality channels. MAR, thus, provides a faster, more stable, and reliable communication channel to mobile users.We have implemented and tested the MAR system in our testbed which spans the networks of three different cellular providers. Through our experiments we have performed a detailed evaluation to quantify the benefits of MAR for different protocols and applications. For example, even in highly mobile environments, MAR, on average, improves the end-user experience of web-browsing and streaming applications by a factor of 2.8 and 4.4 respectively. Our results show that significant benefits can be obtained by exploiting the diversity in coverage offered by many cellular operators, different technology networks (e.g. GPRS, CDMA), and diverse wireless channels.
---
paper_title: DNIS: a middleware for dynamic multiple network interfaces scheduling

paper_content:

Wireless Intelligent Networks Center, Nile University, Smart Village, Egypt Many of today's mobile devices are equipped with multiple network interfaces that can be used to connect to the Internet, including Ethernet, WiFi, 3G, and Bluetooth. However, current operating systems, such as Windows and Linux, typically choose only one of the available network interfaces and assign all the traffic to it, even if more than one is connected to the Internet. This results in an obvious under utilization of the available bandwidth. Different bandwidth aggregation techniques suggested altering different layers of the TCP/IP stack which requires applying modifications on the client's stack and/or the cloud, which cannot be widely deployed easily. In this work, we present DNIS, a networking middleware that achieves bandwidth aggregation using per-TCP connection scheduling on different interfaces in a way that is transparent to both the user and the applications. DNIS is composed of two main components: (1) a parameter estimator that estimates the applications' characteristics and requirements as well as interfaces' properties; (2) a scheduler that uses the estimated parameters to assign different TCP connections to network interfaces. We present an implementation for DNIS for the Windows OS and show its performance for different scheduling algorithms. Our initial results show significant enhancement of the overall device's throughput, up to 54%, increasing resource utilization and enhancing the user's experience.
---
paper_title: DBAS: A Deployable Bandwidth Aggregation System

paper_content:

The explosive increase in data demand coupled with the rapid deployment of various wireless access technologies have led to the increase of number of multi-homed or multi-interface enabled devices. Fully exploiting these interfaces has motivated researchers to propose numerous solutions that aggregate their available bandwidths to increase overall throughput and satisfy the end-user's growing data demand. These solutions, however, have faced a steep deployment barrier that we attempt to overcome in this paper. We propose a Deployable Bandwidth Aggregation System (DBAS) for multi- interface enabled devices. Our system does not introduce any intermediate hardware, modify current operating systems, modify socket implementations, nor require changes to current applications or legacy servers. The DBAS architecture is designed to automatically estimate the characteristics of applications and dynamically schedule various connections or packets to different interfaces. Since our main focus is deployability, we fully implement DBAS on the Windows operating system and evaluate various modes of operation. Our implementation and simulation results show that DBAS achieves up to more than double the throughput gains compared to current operating systems, while operating as an out-of-the- box standard Windows executable, highlighting its deployability.
---
paper_title: Improving throughput and reliability in mobile wireless networks via transport layer bandwidth aggregation

paper_content:

Currently, most battlefield mobile communication devices are equipped with multiple wireless interfaces. The main target of the multiple interfaces is to increase the communication reliability between the soldiers in the battlefield and the command center, so that if one of the interfaces fails, the other interfaces can still provide a communication path. In this case each application data stream is limited to use only one communication channel. Due to the limited and variable bandwidth of the wireless channels, as well as their lossy and break-prone nature, the performance of mobile applications can be greatly hurt. In this paper, we present a transport layer solution for aggregating the bandwidth of the available interfaces. Our solution is based on extending Stream Control Transmission Protocol (SCTP). Our choice to extend SCTP for bandwidth aggregation was motivated by its inherent support for multi-homing. The extended SCTP, which we refer to as Load Sharing-SCTP (LS-SCTP), is able to aggregate the bandwidth of all the active transmission paths between the communicating endpoints. In addition, LS-SCTP dynamically adds/drops communication paths to the aggregated paths bundle. To ensure that the aggregate connection will not stall due to the high loss rate or continuous failure of individual paths, LS-SCTP includes path monitoring and packet assignment mechanisms that distribute the packets on the paths according to their current condition. Simulation results demonstrate the effectiveness of our proposed mechanism in providing throughput and reliability to mobile applications under battlefield conditions.
---
paper_title: A Network Layer Approach to Enable TCP over Multiple Interfaces

paper_content:

The mobile Internet is set to become ubiquitous with the deployment of various wireless technologies. When heterogeneous wireless networks overlap in coverage, a mobile terminal can potentially use multiple wireless interfaces simultaneously. In this paper, we motivate the advantages of simultaneous use of multiple interfaces and present a network layer architecture that supports diverse multi-access services. Our main focus is on one such service provided by the architecture: Bandwidth Aggregation (BAG), specifically for TCP applications.While aggregating bandwidth across multiple interfaces can improve raw throughput, it introduces challenges in the form of packet reordering for TCP applications. When packets are reordered, TCP misinterprets the duplicate ACKS received as indicative of packet loss and invokes congestion control. This can significantly lower TCP throughput and counter any gains that can be had through bandwidth aggregation. To improve overall performance of TCP, we take a two-pronged approach: (1) We propose a scheduling algorithm that partitions traffic onto the different paths (corresponding to each interface) such that reordering is minimized. The algorithm estimates available bandwidth and thereby minimizes reordering by sending packet pairs on the path that introduces the least amount of delay. (2) A buffer management policy is introduced at the client to hide any residual reordering from TCP. We show through simulations that our network-layer approach can achieve good bandwidth aggregation under a variety of network conditions.
---
paper_title: E2EMPT: A transport layer architecture for end-to-end multipath transfer

paper_content:

With the evolving of the network technology, the number of terminal equipping with multiple network interfaces keeps increasing because of the deploying of various access methods and the price descending of access devices. However, the terminals can not make full use of multiple interfaces concurrently in conversional network. In this paper, we motivate the advantages of simultaneously using multiple interfaces and present a transport layer architecture, E2EMPT, which supports end-to-end multipath transfer. E2EMPT (i) exploits path diversity and distributes data adaptively following characters of the end-toend paths, (ii) reduces the effect of reordering when transferring on multiple end-to-end paths, (iii) implements smart path management policies to select appropriate end-to-end paths. Our evaluation using simulations suggests that E2EMPT aggregates bandwidth of the terminal interfaces efficiently, and meanwhile improves the security and reliability of data transfer.
---
paper_title: G-DBAS: A green and deployable bandwidth aggregation system

paper_content:

The widespread deployment of varying networking technologies, coupled with the exponential increase in end-user data demand, have all led to the proliferation of multi-homed or multi-interface enabled devices. To date, these interfaces are mainly utilized one at a time based on network availability, cost, and user-choice. Researchers have recently focused on leveraging these interfaces simultaneously by proposing solutions to aggregate their bandwidths in order to ultimately increase throughput and satisfy the end-user's growing demand on data. These solutions, however, have faced a steep deployment barrier due to various system design choices and heavy demand on energy. In this paper, we propose a novel Green and Deployable Bandwidth Aggregation System (G-DBAS) for multiple interface enabled devices. G-DBAS addresses a set of challenges including automatically estimating the characteristics of applications and scheduling various connections to different interfaces along with meeting different energy consumption goals set by users. We fully implement G-DBAS on the Windows OS and evaluate various scheduling strategies that we propose. Our implementation and simulation results show that G-DBAS can achieve the user energy-throughput goals while operating as an out-of-the-box standard Windows executable, highlighting its deployability and ease of use.
---
paper_title: Design and implementation of a socket-level bandwidth aggregation mechanism for wireless networks

paper_content:

This paper proposes a mechanism to aggregate bandwidth of multiple network interfaces on a computer. Recently one single computer entails multiple different wireless network interfaces, such as IEEE 802.11a/b/g/n, Bluetooth, WiMAX, and so on. They can be combined, and we can aquire broad bandwidth. We designed and developed a Socket-level Bandwidth Aggregation Mechanism (SBAM). SBAM can aggregate multiple interfaces on a computer to offer broad bandwidth. In addition, implementation in socket layer causes easy deployment and adaptation to existing environment. We evaluated SBAM under actual wireless network environments. SBAM offers broad bandwidth by utilizing various wireless devices on a computer while it avoids modification to existing environment.
---
paper_title: Cross-layer FPS: A SCTP-based cross-layer data scheduling approach

paper_content:

In heterogeneous wireless networks, multi-interfaced mobile terminals may be connected to links with rapidly varying MAC and physical characteristics. On the other hand, current deployment of communication protocols rely on the information available at associated layer only. In order to improve transport layer performance for multi-homed mobile terminals, we propose a cross-layer approach to schedule data over multiple available paths. Our data-striping approach strengthens the cooperation between higher and lower layers and enables transport layer mechanism to exploit information provided by MAC layer. We compare our approach with existing techniques and prove that our cross-layer system improves multipath performance over single-layer multipath systems.
---
paper_title: An architecture for packet-striping protocols

paper_content:

Link-striping algorithms are often used to overcome transmission bottlenecks in computer networks. Traditional striping algorithms suffer from two major disadvantages. They provide inadequate load sharing in the presence of variable-length packets, and may result in non-FIFO delivery of data. We describe a new family of link-striping algorithms that solves both problems. Our scheme applies to any layer that can provide multiple FIFO channels. We deal with variable-sized packets by showing how fair-queuing algorithms can be transformed into load-sharing algorithms. Our transformation results in practical load-sharing protocols, and shows a theoretical connection between two seemingly different problems. The same transformation can be applied to obtain load-sharing protocols for links with different capacities. We deal with the FIFO requirement for two separate cases. If a sequence number can be added to each packet, we show how to speed up packet processing by letting the receiver simulate the sender algorithm. If no header can be added, we show how to provide quasi FIFO delivery. Quasi FIFO is FIFO except during occasional periods of loss of synchronization. We argue that quasi FIFO is adequate for most applications. We also describe a simple technique for speedy restoration of synchronization in the event of loss. We develop an architectural framework for transparently embedding our protocol at the network level by striping IP packets across multiple physical interfaces. The resulting stripe protocol has been implemented within the NetBSD kernel. Our measurements and simulations show that the protocol offers scalable throughput even when striping is done over dissimilar links, and that the protocol synchronized quickly after packet loss. Measurements show performance improvements over conventional round-robin striping schemes and striping schemes that do not resequence packets. Some aspects of our solution have been implemented in Cisco's router operating system (IOS 11.3) in the context of Multilink PPP striping.
---
paper_title: Transport level mechanisms for bandwidth aggregation on mobile hosts

paper_content:

Present mobile computing does not support the simultaneous use of multiple heterogeneous network interfaces for a single transport layer connection. We describe a solution for channel aggregation at the transport layer, which provides increased bandwidth to mobile nodes. We present R-MTP (reliable multiplexing transport protocol), a rate-based reliable transport protocol capable of multiplexing data from a single application data stream across multiple network interfaces. Due to the lossy nature of wireless links in mobile environments, R-MTP tracks packet interarrival time for discrimination between congestion-based and transmission-based losses as well as better bandwidth estimation. The challenges to such a reliable protocol lie in the coordination of packets across streams with varying channel characteristics. Our experimental results validate R-MTP's bandwidth estimation and loss characterization techniques. Successful bandwidth aggregation is demonstrated in ideal and lossy environments.
---
paper_title: A network-layer proxy for bandwidth aggregation and reduction of IP packet reordering

paper_content:

With today's widespread deployment of wireless technologies, it is often the case that a single communication device can select from a variety of access networks. At the same time, there is an ongoing trend towards integration of multiple network interfaces into end-hosts, such as cell phones with HSDPA, Bluetooth and WLAN. By using multiple Internet connections concurrently, network applications can benefit from aggregated bandwidth and increased fault tolerance. However, the heterogeneity of wireless environments introduce challenges with respect to implementation, deployment, and protocol compatibility. Variable link characteristics cause reordering when sending IP packets of the same flow over multiple paths. This paper introduces a multilink proxy that is able to transparently stripe traffic destined for multihomed clients. Operating on the network layer, the proxy uses path monitoring statistics to adapt to changes in throughput and latency. Experimental results obtained from a proof-of-concept implementation verify that our approach is able to fully aggregate the throughput of heterogeneous downlink streams, even if the path characteristics change over time. In addition, our novel method of equalizing delays by buffering packets on the proxy significantly reduces IP packet reordering and the buffer requirements of clients.
---
paper_title: OPERETTA: An optimal energy efficient bandwidth aggregation system

paper_content:

The widespread deployment of varying networking technologies, coupled with the exponential increase in end-user data demand, have led to the proliferation of multi-homed or multi-interface enabled devices. To date, these interfaces are mainly utilized one at a time based on network availability, cost, and user-choice. While researchers have focused on simultaneously leveraging these interfaces by aggregating their bandwidths, these solutions however, have faced a steep deployment barrier. In this paper, we propose a novel optimal, energy-efficient, and deployable bandwidth aggregation system (OPERETTA) for multiple interface enabled devices. OPERETTA satisfies three goals: achieving a user defined throughput level with optimal energy consumption over multiple interfaces, deployability without changes to current legacy servers, and leveraging incremental deployment to achieve increased performance gains. We present the OPERETTA architecture and formulate the optimal scheduling problem as a mixed integer programming problem yielding an efficient solution. We evaluate OPERETTA via implementation on the the Windows OS, and further verify our results with simulations on NS2. Our evaluation shows the tradeoffs between the energy and throughput goals. Furthermore, with no modifications to current legacy servers, OPERETTA achieves throughput gains up to 150% compared to current operating systems with the same energy consumption. In addition, with as few as 25% of the servers becoming OPERETTA enabled, OPERETTA performance reaches the throughput upper bound, highlighting its incremental deployment and performance gains.
---
paper_title: A Data-Scheduling Mechanism for Multi-Homed Mobile Terminals with Disparate Link Latencies

paper_content:

A mobile terminal equipped with multiple network interfaces can often be found under coverage of multiple access networks. Multihoming enables mobile terminals to communicate simultaneously through multiple interfaces. Connection-oriented transport layer mechanisms ensure reliable, in-order delivery of data, however parallel data transfers in multihoming face problems due to out-of-order reception of data which causes fast-retransmissions and limit the communication throughput. In this paper, we propose a transport layer based mechanism which stripes one flow''s data across multiple disjoint paths efficiently, reducing possible occurrence of out-of-order data. Our mechanism estimates arrival times of data packets to be sent through available paths in an association, and decides which packets are to be sent through each path. We compared our mechanism with a relatively closer approach called Westwood SCTP. We illustrate with the help of simulation results that our mechanism proves to improve multipath communication.
---
paper_title: A Packet Partition Scheduling Mechanism for Bandwidth Aggregation over Multiple Paths

paper_content:

This paper proposes a packet partition scheduling mechanism for bandwidth aggregation over end-to-end multi-path through multiple network interfaces. The proposed mechanism effectively partitions packets on the appropriate end-to-end path through the corresponding network interface. Each network interface is considered to have a partition counter associated with it. This partition counter varied by both weighted capacity and partitioned packets is used to determine if a network interface has enough credits to partition incoming packets on multiple paths. The capacity unit is shown to be a useful design parameter to make the performance of the proposed mechanism as good as possible. Through computer simulations, it is shown that the proposed mechanism can partition well randomly incoming packets for the multi-path communication and can outperform the simple weighted packet partition scheduling mechanism.
---
paper_title: MAR: a commuter router infrastructure for the mobile Internet

paper_content:

We introduce MAR, a commuter mobile access router infrastructure that exploits wireless diversity (e.g. channel diversity, network diversity, and technology diversity) to provide improved data performance for wireless data users. Our system design stems from the observation that rather than choosing a single wireless service provider (e.g. Sprint, AT&T, BT, Vodafone), a single technology (e.g. GPRS, UMTS, CDMA, 802.11), or a single wireless channel, users can obtain significant benefits by using the multiplicity of choices available. MAR is a wireless multi-homed device that can be placed in moving vehicles (e.g. car, bus, train) to enable high-speed data access. MAR dynamically instantiates new channels based on traffic demand, aggregates the bandwidth and dynamically shifts load from poor quality to better quality channels. MAR, thus, provides a faster, more stable, and reliable communication channel to mobile users.We have implemented and tested the MAR system in our testbed which spans the networks of three different cellular providers. Through our experiments we have performed a detailed evaluation to quantify the benefits of MAR for different protocols and applications. For example, even in highly mobile environments, MAR, on average, improves the end-user experience of web-browsing and streaming applications by a factor of 2.8 and 4.4 respectively. Our results show that significant benefits can be obtained by exploiting the diversity in coverage offered by many cellular operators, different technology networks (e.g. GPRS, CDMA), and diverse wireless channels.
---
paper_title: DNIS: a middleware for dynamic multiple network interfaces scheduling

paper_content:

Wireless Intelligent Networks Center, Nile University, Smart Village, Egypt Many of today's mobile devices are equipped with multiple network interfaces that can be used to connect to the Internet, including Ethernet, WiFi, 3G, and Bluetooth. However, current operating systems, such as Windows and Linux, typically choose only one of the available network interfaces and assign all the traffic to it, even if more than one is connected to the Internet. This results in an obvious under utilization of the available bandwidth. Different bandwidth aggregation techniques suggested altering different layers of the TCP/IP stack which requires applying modifications on the client's stack and/or the cloud, which cannot be widely deployed easily. In this work, we present DNIS, a networking middleware that achieves bandwidth aggregation using per-TCP connection scheduling on different interfaces in a way that is transparent to both the user and the applications. DNIS is composed of two main components: (1) a parameter estimator that estimates the applications' characteristics and requirements as well as interfaces' properties; (2) a scheduler that uses the estimated parameters to assign different TCP connections to network interfaces. We present an implementation for DNIS for the Windows OS and show its performance for different scheduling algorithms. Our initial results show significant enhancement of the overall device's throughput, up to 54%, increasing resource utilization and enhancing the user's experience.
---
paper_title: DBAS: A Deployable Bandwidth Aggregation System

paper_content:

The explosive increase in data demand coupled with the rapid deployment of various wireless access technologies have led to the increase of number of multi-homed or multi-interface enabled devices. Fully exploiting these interfaces has motivated researchers to propose numerous solutions that aggregate their available bandwidths to increase overall throughput and satisfy the end-user's growing data demand. These solutions, however, have faced a steep deployment barrier that we attempt to overcome in this paper. We propose a Deployable Bandwidth Aggregation System (DBAS) for multi- interface enabled devices. Our system does not introduce any intermediate hardware, modify current operating systems, modify socket implementations, nor require changes to current applications or legacy servers. The DBAS architecture is designed to automatically estimate the characteristics of applications and dynamically schedule various connections or packets to different interfaces. Since our main focus is deployability, we fully implement DBAS on the Windows operating system and evaluate various modes of operation. Our implementation and simulation results show that DBAS achieves up to more than double the throughput gains compared to current operating systems, while operating as an out-of-the- box standard Windows executable, highlighting its deployability.
---
paper_title: GreenBag: Energy-Efficient Bandwidth Aggregation for Real-Time Streaming in Heterogeneous Mobile Wireless Networks

paper_content:

Modern mobile devices are equipped with multiple network interfaces, including 3G/LTE and WiFi. Bandwidth aggregation over LTE and WiFi links offers an attractive opportunity of supporting bandwidth-intensive services, such as high-quality video streaming, on mobile devices. However, achieving effective bandwidth aggregation in mobile environments raises several challenges related to deployment, link heterogeneity, network fluctuation, and energy consumption. We present GreenBag, an energy-efficient bandwidth aggregation middleware that supports real-time data-streaming services over asymmetric wireless links, requiring no modifications to the existing Internet infrastructure and servers. GreenBag employs several techniques, including medium load balancing, efficient segment management, and energy-aware mode control, to resolve such challenges. We implement a prototype of GreenBag on Android-based mobile devices which hosts, to the best knowledge of the authors, the first LTE-enabled bandwidth aggregation prototype for energy-efficient real-time video streaming. Our experiment results in both emulated and real-world environments show that GreenBag not only achieves good bandwidth aggregation to provide QoS in bandwidth-scarce environments but also efficiently saves energy on mobile devices. Moreover, energy-aware GreenBag can minimize video interruption while consuming 14-25% less energy than the non-energy-aware counterpart in real-world experiments.
---
paper_title: Improved data distribution for multipath TCP communication

paper_content:

Multi-homed environments are increasingly common, especially for mobile users. To efficiently utilize multiple access lines for single file transfer, multipath TCP communication methods have been proposed. A multipath TCP enables simultaneous distributed data transfer between two end-points on multiple TCP connections. However, these methods cannot fully utilize the available bandwidth of multiple paths because they do not properly consider the end-to-end delay of packet transmission, so out-of-order data arrival at a receiver causes a bottleneck in data sort operations. This problem is more severe in environments where the quality of each path is different or unstable, such as in wireless environments. To solve this problem, we propose a multipath TCP communication method that includes a data distribution method to enable in-order delivery at a receiver. We call this arrival-time matching load-balancing (ATLB). ATLB continuously calculates the delay of each path, including the TCP queuing delay at a sender and the network delay, and then sends a data segment through the TCP connection with the lowest end-to-end delay. Simulation results show that ATLB improves end-to-end throughput, especially in heterogeneous environments where the quality of paths differs. For example, ATLB enabled twice the throughput with the conventional multipath TCP. We also report performance evaluation results from our ATLB test bed system in a wireless network environment. Our ATLB test bed system was able to fully utilize the aggregate available bandwidth of unstable multiple wireless links.
---
paper_title: LS-SCTP: a bandwidth aggregation technique for stream control transmission protocol

paper_content:

Stream Control Transmission Protocol (SCTP) specifications utilize the multiple paths capabilities between the sender and receiver for retransmission of lost data chunks and as a backup in case of primary path failure. Under normal conditions, all data chunks are sent on the primary path chosen by the SCTP user during the transport connection initiation. In this paper, we address in detail various aspects related to extending and engineering SCTP in order to utilize the available paths for simultaneous transmission of data chunks, while maintaining the SCTP congestion control on each path so as to ensure fair integration with other traffic in the network. The extended SCTP, referred to as Load-Sharing SCTP (LS-SCTP), is able to aggregate the bandwidth of all the active transmission paths between the communicating endpoints. LS-SCTP monitors the paths, and accordingly it chooses the paths that are suitable for load sharing. LS-SCTP retransmission mechanism accelerates the delivery of missing data to the receiver in order to prevent stalling the transport connection while waiting for missing data chunks. Simulation results show that LS-SCTP is extremely beneficial for networks with limited bandwidth, high loss rate and failure prone links.
---
paper_title: Westwood SCTP: load balancing over multipaths using bandwidth-aware source scheduling

paper_content:

While it is more and more usual to buy computer equipment with multiple network interfaces, and the proliferation of ISPs for both wired and wireless users provides different solutions to access the network core, upper layers across the protocol spectrum seem unprepared to accept the challenge posed by multiple interfaces and, consequently, by multiple paths between the same source-destination pair. This paper tries to partially answer this challenge by proposing an enhancement of the SCTP protocol that aims at balancing load across multiple connections on disjoint paths in an accurate fashion, through the knowledge of bandwidth estimation on each path. Some results confirm the viability of the approach and invite further research.
---
paper_title: A novel mechanism for data streaming across multiple IP links for improving throughput and reliability in mobile environments

paper_content:

With ubiquitous computing and network access, multiple network conduits are becoming available to mobile as well as static hosts. Selection of the preferred mode of data transfer is a dynamic optimization problem depending on the type of application, its bandwidth/latency/jitter requirements, current network status, cost, power consumption, battery life, and so on. Furthermore, since wireless bandwidth is likely to remain a scarce resource, we foresee scenarios wherein mobile hosts require simultaneous data transfer across multiple IP interfaces to obtain higher overall bandwidth. We present a brief overview of related work identifying schemes that might be applicable to the problem, along with their feasibility, and pros and cons. We then propose a new mechanism to aggregate the bandwidth of multiple IP links by splitting a data flow across multiple network interfaces at the IP level. Our method is transparent to transport (TCP/UDP) and higher layers. We have analyzed the performance characteristics of the aggregation scheme and demonstrated significant gain when the links being aggregated have similar bandwidth and latency. The use of multiple interfaces also enhances reliability. Our analysis identifies the conditions under which the proposed scheme, or any other scheme that stripes a single TCP connection across multiple IP links, can be used to enhance throughput. Several interesting directions for future work have also been identified.
---
paper_title: OSCAR: A Collaborative Bandwidth Aggregation System

paper_content:

The exponential increase in mobile data demand, coupled with growing user expectation to be connected in all places at all times, have introduced novel challenges for researchers to address. Fortunately, the wide spread deployment of various network technologies and the increased adoption of multi-interface enabled devices have enabled researchers to develop solutions for those challenges. Such solutions aim to exploit available interfaces on such devices in both solitary and collaborative forms. These solutions, however, have faced a steep deployment barrier. ::: In this paper, we present OSCAR, a multi-objective, incentive-based, collaborative, and deployable bandwidth aggregation system. We present the OSCAR architecture that does not introduce any intermediate hardware nor require changes to current applications or legacy servers. The OSCAR architecture is designed to automatically estimate the system's context, dynamically schedule various connections and/or packets to different interfaces, be backwards compatible with the current Internet architecture, and provide the user with incentives for collaboration. We also formulate the OSCAR scheduler as a multi-objective, multi-modal scheduler that maximizes system throughput while minimizing energy consumption or financial cost. We evaluate OSCAR via implementation on Linux, as well as via simulation, and compare our results to the current optimal achievable throughput, cost, and energy consumption. Our evaluation shows that, in the throughput maximization mode, we provide up to 150% enhancement in throughput compared to current operating systems, without any changes to legacy servers. Moreover, this performance gain further increases with the availability of connection resume-supporting, or OSCAR-enabled servers, reaching the maximum achievable upper-bound throughput.
---
paper_title: End-to-End Inverse Multiplexing for Mobile Hosts

paper_content:

This paper presents a framework for the creation of transport protocols for mobile hosts that use multiple link layers simultaneously for the same connection. This abstraction provides an end-to-end transport layer channel between two applications that do not have to be aware of host mobility. The channel is composed of multiple network layer sub-channels. A sub-channel is an end-to-end network layer connection that is mapped to one physical interface. Inverse multiplexing is used at the transport level to divide application data into sub-channels, and a rate-based transmission mechanism provides congestion avoidance. The same mechanism is used to differentiate transmission losses from congestion losses, resulting in good throughput in lossy wireless links. Experimental results for two protocols created using this framework validate our design choices.
---
paper_title: An architecture for packet-striping protocols

paper_content:

Link-striping algorithms are often used to overcome transmission bottlenecks in computer networks. Traditional striping algorithms suffer from two major disadvantages. They provide inadequate load sharing in the presence of variable-length packets, and may result in non-FIFO delivery of data. We describe a new family of link-striping algorithms that solves both problems. Our scheme applies to any layer that can provide multiple FIFO channels. We deal with variable-sized packets by showing how fair-queuing algorithms can be transformed into load-sharing algorithms. Our transformation results in practical load-sharing protocols, and shows a theoretical connection between two seemingly different problems. The same transformation can be applied to obtain load-sharing protocols for links with different capacities. We deal with the FIFO requirement for two separate cases. If a sequence number can be added to each packet, we show how to speed up packet processing by letting the receiver simulate the sender algorithm. If no header can be added, we show how to provide quasi FIFO delivery. Quasi FIFO is FIFO except during occasional periods of loss of synchronization. We argue that quasi FIFO is adequate for most applications. We also describe a simple technique for speedy restoration of synchronization in the event of loss. We develop an architectural framework for transparently embedding our protocol at the network level by striping IP packets across multiple physical interfaces. The resulting stripe protocol has been implemented within the NetBSD kernel. Our measurements and simulations show that the protocol offers scalable throughput even when striping is done over dissimilar links, and that the protocol synchronized quickly after packet loss. Measurements show performance improvements over conventional round-robin striping schemes and striping schemes that do not resequence packets. Some aspects of our solution have been implemented in Cisco's router operating system (IOS 11.3) in the context of Multilink PPP striping.
---
paper_title: OPERETTA: An optimal energy efficient bandwidth aggregation system

paper_content:

The widespread deployment of varying networking technologies, coupled with the exponential increase in end-user data demand, have led to the proliferation of multi-homed or multi-interface enabled devices. To date, these interfaces are mainly utilized one at a time based on network availability, cost, and user-choice. While researchers have focused on simultaneously leveraging these interfaces by aggregating their bandwidths, these solutions however, have faced a steep deployment barrier. In this paper, we propose a novel optimal, energy-efficient, and deployable bandwidth aggregation system (OPERETTA) for multiple interface enabled devices. OPERETTA satisfies three goals: achieving a user defined throughput level with optimal energy consumption over multiple interfaces, deployability without changes to current legacy servers, and leveraging incremental deployment to achieve increased performance gains. We present the OPERETTA architecture and formulate the optimal scheduling problem as a mixed integer programming problem yielding an efficient solution. We evaluate OPERETTA via implementation on the the Windows OS, and further verify our results with simulations on NS2. Our evaluation shows the tradeoffs between the energy and throughput goals. Furthermore, with no modifications to current legacy servers, OPERETTA achieves throughput gains up to 150% compared to current operating systems with the same energy consumption. In addition, with as few as 25% of the servers becoming OPERETTA enabled, OPERETTA performance reaches the throughput upper bound, highlighting its incremental deployment and performance gains.
---
paper_title: The PPP Multilink Protocol (MP)

paper_content:

This document proposes a method for splitting, recombining and sequencing datagrams across multiple logical data links. This work was originally motivated by the desire to exploit multiple bearer channels in ISDN, but is equally applicable to any situation in which multiple PPP links connect two systems, including async links. This is accomplished by means of new PPP [2] options and protocols.
---
paper_title: DBAS: A Deployable Bandwidth Aggregation System

paper_content:

The explosive increase in data demand coupled with the rapid deployment of various wireless access technologies have led to the increase of number of multi-homed or multi-interface enabled devices. Fully exploiting these interfaces has motivated researchers to propose numerous solutions that aggregate their available bandwidths to increase overall throughput and satisfy the end-user's growing data demand. These solutions, however, have faced a steep deployment barrier that we attempt to overcome in this paper. We propose a Deployable Bandwidth Aggregation System (DBAS) for multi- interface enabled devices. Our system does not introduce any intermediate hardware, modify current operating systems, modify socket implementations, nor require changes to current applications or legacy servers. The DBAS architecture is designed to automatically estimate the characteristics of applications and dynamically schedule various connections or packets to different interfaces. Since our main focus is deployability, we fully implement DBAS on the Windows operating system and evaluate various modes of operation. Our implementation and simulation results show that DBAS achieves up to more than double the throughput gains compared to current operating systems, while operating as an out-of-the- box standard Windows executable, highlighting its deployability.
---
paper_title: Intentional networking: opportunistic exploitation of mobile network diversity

paper_content:

Mobile devices face a diverse and dynamic set of networking options. Using those options to the fullest requires knowledge of application intent. This paper describes Intentional Networking, a simple but powerful mechanism for handling network diversity. Applications supply a declarative label for network transmissions, and the system matches transmissions to the most appropriate network. The system may also defer and re-order opportunistic transmissions subject to application-supplied mutual exclusion and ordering constraints. We have modified three applications to use Intentional Networking: BlueFS, a distributed file system for pervasive computing, Mozilla's Thunderbird e-mail client, and a vehicular participatory sensing application. We evaluated the performance of these applications using measurements obtained by driving a vehicle through WiFi and cellular 3G network coverage. Compared to an idealized solution that makes optimal use of all aggregated available networks but that lacks knowledge of application intent, Intentional Networking improves the latency of interactive messages from 48% to 13x, while adding no more than 7% throughput overhead.
---
paper_title: Multipath Binomial Congestion Control Algorithms

paper_content:

Nowadays portable devices with multiple wireless interfaces and using multimedia services are becoming more popular on the Internet. This paper describes a family of multipath binomial congestion control algorithms for audio/video streaming, where a low variant of transmission rate is important. We extend the fluid model of binomial algorithms for single-path transmission to support the concurrent transmission of packets across multiple paths. We focus on the extension of two particular algorithms, SQRT and IIAD, for multiple paths, called MPSQRT and MPIIAD, respectively. Additionally, we apply the design technique (using the multipath fluid model) for multipath TCP (MPTCP) into the extension of SQRT and IIAD, called fbMPSQRT and fbMPIIAD, respectively. Both two approaches ensure that multipath binomial congestion control algorithms achieve load-balancing, throughput improvement, and fairness to single-path binomial algorithms at shared bottlenecks. Through the simulations and comparison with the uncoordinated protocols MPSQRT/MPIIAD, fbMPSQRT/fbMPIIAD and MPTCP, we find that our extended multipath transport protocols can preserve lower latency and transmission rate variance than MPTCP, fairly share with single-path SQRT/IIAD, MPTCP and TCP, and also can achieve throughput improvements and load-balancing equivalent to those of MPTCP under various scenarios and network conditions. key words: multipath binomial congestion control, multimedia streaming, fairness, load-balancing
---
paper_title: Handheld routers: intelligent bandwidth aggregation for mobile collaborative communities

paper_content:

Multi-homed, mobile wireless computing and communication devices can spontaneously form communities to logically combine and share the bandwidth of each other's wide-area communication links using inverse multiplexing. But membership in such a community can be highly dynamic, as devices and their associated WAN links randomly join and leave the community. We identify the issues and tradeoffs faced in designing a decentralized inverse multiplexing system in this challenging setting, and determine precisely how heterogeneous WAN links should be characterized, and when they should be added to, or deleted from, the shared pool. We then propose methods of choosing the appropriate channels on which to assign newly-arriving application flows. Using video traffic as a motivating example, we demonstrate how significant performance gains can be realized by adapting allocation of the shared WAN channels to specific application requirements. Our simulation and experimentation results show that collaborative bandwidth aggregation systems are, indeed, a practical and compelling means of achieving high-speed Internet access for groups of wireless computing devices beyond the reach of public or private access points.
---
paper_title: MOTA: engineering an operator agnostic mobile service

paper_content:

There are two emerging trends in the mobile data world. First, mobile data is exploding at a rapid rate with analysts predicting 25-50X growth by the year 2015. The second trend is that users are demanding greater degree of flexibility in selecting their operators at fine timescales. Across Asia, dual-SIM phones have become popular, while Apple is rumored to be designing a Universal SIM that will allow iPhone users to toggle between different operators. This latter trend points towards an impending disruption in wireless service models which could also be the need of the hour from the spectrum shortage perspective. This points towards a new service model where users can choose an operator based on application needs. However, if users make this choice greedily without network assistance, it can exacerbate spectrum scarcity and degrade user experience. In this work, we consider user devices with multiple network interfaces (3G, LTE etc.) that can be simultaneously active and each running multiple applications. We propose the MOTA service model to enable users to associate each interface with the operator of choice at fine time scales. Under the MOTA service model, through concise signalling information, operators provide information about their own network, so that each user can (i) choose a suitable operator for each interface, and (ii) choose an interface for each active application. We make the following contributions in this paper. First, we propose concise network signalling that assists users to make informed choices even under mobility. Second, we develop user-choice algorithms that maximize a suitable notion of user satisfaction while using spectrum resources efficiently. Third, we perform extensive evaluation over actual base station deployment in a city coupled with real signal propagation maps. Our results with two operators show that, MOTA service model provides capacity gain in the range 2.5-4X over the current existing service model. Finally, we argue that our solution is practically implementable by combining appropriate IEEE standards and IETF proposals.
---
paper_title: OPERETTA: An optimal energy efficient bandwidth aggregation system

paper_content:

The widespread deployment of varying networking technologies, coupled with the exponential increase in end-user data demand, have led to the proliferation of multi-homed or multi-interface enabled devices. To date, these interfaces are mainly utilized one at a time based on network availability, cost, and user-choice. While researchers have focused on simultaneously leveraging these interfaces by aggregating their bandwidths, these solutions however, have faced a steep deployment barrier. In this paper, we propose a novel optimal, energy-efficient, and deployable bandwidth aggregation system (OPERETTA) for multiple interface enabled devices. OPERETTA satisfies three goals: achieving a user defined throughput level with optimal energy consumption over multiple interfaces, deployability without changes to current legacy servers, and leveraging incremental deployment to achieve increased performance gains. We present the OPERETTA architecture and formulate the optimal scheduling problem as a mixed integer programming problem yielding an efficient solution. We evaluate OPERETTA via implementation on the the Windows OS, and further verify our results with simulations on NS2. Our evaluation shows the tradeoffs between the energy and throughput goals. Furthermore, with no modifications to current legacy servers, OPERETTA achieves throughput gains up to 150% compared to current operating systems with the same energy consumption. In addition, with as few as 25% of the servers becoming OPERETTA enabled, OPERETTA performance reaches the throughput upper bound, highlighting its incremental deployment and performance gains.
---
paper_title: MAR: a commuter router infrastructure for the mobile Internet

paper_content:

We introduce MAR, a commuter mobile access router infrastructure that exploits wireless diversity (e.g. channel diversity, network diversity, and technology diversity) to provide improved data performance for wireless data users. Our system design stems from the observation that rather than choosing a single wireless service provider (e.g. Sprint, AT&T, BT, Vodafone), a single technology (e.g. GPRS, UMTS, CDMA, 802.11), or a single wireless channel, users can obtain significant benefits by using the multiplicity of choices available. MAR is a wireless multi-homed device that can be placed in moving vehicles (e.g. car, bus, train) to enable high-speed data access. MAR dynamically instantiates new channels based on traffic demand, aggregates the bandwidth and dynamically shifts load from poor quality to better quality channels. MAR, thus, provides a faster, more stable, and reliable communication channel to mobile users.We have implemented and tested the MAR system in our testbed which spans the networks of three different cellular providers. Through our experiments we have performed a detailed evaluation to quantify the benefits of MAR for different protocols and applications. For example, even in highly mobile environments, MAR, on average, improves the end-user experience of web-browsing and streaming applications by a factor of 2.8 and 4.4 respectively. Our results show that significant benefits can be obtained by exploiting the diversity in coverage offered by many cellular operators, different technology networks (e.g. GPRS, CDMA), and diverse wireless channels.
---
paper_title: Multipath TCP algorithms: theory and design

paper_content:

Multi-path TCP (MP-TCP) has the potential to greatly improve application performance by using multiple paths transparently. We propose a fluid model for a large class of MP-TCP algorithms and identify design criteria that guarantee the existence, uniqueness, and stability of system equilibrium. We characterize algorithm parameters for TCP-friendliness and prove an inevitable tradeoff between responsiveness and friendliness. We discuss the implications of these properties on the behavior of existing algorithms and motivate a new design that generalizes existing algorithms. We use ns2 simulations to evaluate the proposed algorithm and illustrate its superior overall performance.
---
paper_title: E2EMPT: A transport layer architecture for end-to-end multipath transfer

paper_content:

With the evolving of the network technology, the number of terminal equipping with multiple network interfaces keeps increasing because of the deploying of various access methods and the price descending of access devices. However, the terminals can not make full use of multiple interfaces concurrently in conversional network. In this paper, we motivate the advantages of simultaneously using multiple interfaces and present a transport layer architecture, E2EMPT, which supports end-to-end multipath transfer. E2EMPT (i) exploits path diversity and distributes data adaptively following characters of the end-toend paths, (ii) reduces the effect of reordering when transferring on multiple end-to-end paths, (iii) implements smart path management policies to select appropriate end-to-end paths. Our evaluation using simulations suggests that E2EMPT aggregates bandwidth of the terminal interfaces efficiently, and meanwhile improves the security and reliability of data transfer.
---
paper_title: An architecture for packet-striping protocols

paper_content:

Link-striping algorithms are often used to overcome transmission bottlenecks in computer networks. Traditional striping algorithms suffer from two major disadvantages. They provide inadequate load sharing in the presence of variable-length packets, and may result in non-FIFO delivery of data. We describe a new family of link-striping algorithms that solves both problems. Our scheme applies to any layer that can provide multiple FIFO channels. We deal with variable-sized packets by showing how fair-queuing algorithms can be transformed into load-sharing algorithms. Our transformation results in practical load-sharing protocols, and shows a theoretical connection between two seemingly different problems. The same transformation can be applied to obtain load-sharing protocols for links with different capacities. We deal with the FIFO requirement for two separate cases. If a sequence number can be added to each packet, we show how to speed up packet processing by letting the receiver simulate the sender algorithm. If no header can be added, we show how to provide quasi FIFO delivery. Quasi FIFO is FIFO except during occasional periods of loss of synchronization. We argue that quasi FIFO is adequate for most applications. We also describe a simple technique for speedy restoration of synchronization in the event of loss. We develop an architectural framework for transparently embedding our protocol at the network level by striping IP packets across multiple physical interfaces. The resulting stripe protocol has been implemented within the NetBSD kernel. Our measurements and simulations show that the protocol offers scalable throughput even when striping is done over dissimilar links, and that the protocol synchronized quickly after packet loss. Measurements show performance improvements over conventional round-robin striping schemes and striping schemes that do not resequence packets. Some aspects of our solution have been implemented in Cisco's router operating system (IOS 11.3) in the context of Multilink PPP striping.
---
paper_title: OPERETTA: An optimal energy efficient bandwidth aggregation system

paper_content:

The widespread deployment of varying networking technologies, coupled with the exponential increase in end-user data demand, have led to the proliferation of multi-homed or multi-interface enabled devices. To date, these interfaces are mainly utilized one at a time based on network availability, cost, and user-choice. While researchers have focused on simultaneously leveraging these interfaces by aggregating their bandwidths, these solutions however, have faced a steep deployment barrier. In this paper, we propose a novel optimal, energy-efficient, and deployable bandwidth aggregation system (OPERETTA) for multiple interface enabled devices. OPERETTA satisfies three goals: achieving a user defined throughput level with optimal energy consumption over multiple interfaces, deployability without changes to current legacy servers, and leveraging incremental deployment to achieve increased performance gains. We present the OPERETTA architecture and formulate the optimal scheduling problem as a mixed integer programming problem yielding an efficient solution. We evaluate OPERETTA via implementation on the the Windows OS, and further verify our results with simulations on NS2. Our evaluation shows the tradeoffs between the energy and throughput goals. Furthermore, with no modifications to current legacy servers, OPERETTA achieves throughput gains up to 150% compared to current operating systems with the same energy consumption. In addition, with as few as 25% of the servers becoming OPERETTA enabled, OPERETTA performance reaches the throughput upper bound, highlighting its incremental deployment and performance gains.
---
paper_title: A Data-Scheduling Mechanism for Multi-Homed Mobile Terminals with Disparate Link Latencies

paper_content:

A mobile terminal equipped with multiple network interfaces can often be found under coverage of multiple access networks. Multihoming enables mobile terminals to communicate simultaneously through multiple interfaces. Connection-oriented transport layer mechanisms ensure reliable, in-order delivery of data, however parallel data transfers in multihoming face problems due to out-of-order reception of data which causes fast-retransmissions and limit the communication throughput. In this paper, we propose a transport layer based mechanism which stripes one flow''s data across multiple disjoint paths efficiently, reducing possible occurrence of out-of-order data. Our mechanism estimates arrival times of data packets to be sent through available paths in an association, and decides which packets are to be sent through each path. We compared our mechanism with a relatively closer approach called Westwood SCTP. We illustrate with the help of simulation results that our mechanism proves to improve multipath communication.
---
paper_title: Architecture, Implementation, and Evaluation of a Concurrent Multi-path Real-time Transport Control Protocol

paper_content:

Current multimedia applications utilize a combination of real-time transport protocol (RTP) and user datagram protocol (UDP) for transmitting real-time streams across the network. Bandwidth aggregation over multiple paths for improved real-time stream transmission can be achieved using either a combination of multi-flow RTP (MRTP) and UDP, or various adaptations of Partial reliability (PR) extension of SCTP (SCTP-PR). However, they are not really useful for balancing load on the multiple paths. The receiving end of these protocols can neither identify late arriving packets nor notify the sender about them. The novel concurrent multi-path real-time transmission control protocol (cmpRTCP) proposed, implemented, and evaluated in this work not only overcomes the problems faced by existing multi-path protocols, but also preserves the novel design and implementation features of the recently proposed cmpTCP. This protocol which has a congestion controller and a packet scheduler embedded in its core, intelligently exploits the availability of multiple paths between multi-homed hosts for concurrent transmission and showcases the ability of (i) remaining TCP-friendly while aggregating bandwidth, (ii) balancing load across paths by scheduling more packets on less congested paths, (iii) increasing end-to-end connection reliability by using multiple paths and (iv) improving QoS at the receiving end by scheduling more packets on better paths.
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paper_title: The PPP Multilink Protocol (MP)

paper_content:

This document proposes a method for splitting, recombining and sequencing datagrams across multiple logical data links. This work was originally motivated by the desire to exploit multiple bearer channels in ISDN, but is equally applicable to any situation in which multiple PPP links connect two systems, including async links. This is accomplished by means of new PPP [2] options and protocols.
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paper_title: MAR: a commuter router infrastructure for the mobile Internet

paper_content:

We introduce MAR, a commuter mobile access router infrastructure that exploits wireless diversity (e.g. channel diversity, network diversity, and technology diversity) to provide improved data performance for wireless data users. Our system design stems from the observation that rather than choosing a single wireless service provider (e.g. Sprint, AT&T, BT, Vodafone), a single technology (e.g. GPRS, UMTS, CDMA, 802.11), or a single wireless channel, users can obtain significant benefits by using the multiplicity of choices available. MAR is a wireless multi-homed device that can be placed in moving vehicles (e.g. car, bus, train) to enable high-speed data access. MAR dynamically instantiates new channels based on traffic demand, aggregates the bandwidth and dynamically shifts load from poor quality to better quality channels. MAR, thus, provides a faster, more stable, and reliable communication channel to mobile users.We have implemented and tested the MAR system in our testbed which spans the networks of three different cellular providers. Through our experiments we have performed a detailed evaluation to quantify the benefits of MAR for different protocols and applications. For example, even in highly mobile environments, MAR, on average, improves the end-user experience of web-browsing and streaming applications by a factor of 2.8 and 4.4 respectively. Our results show that significant benefits can be obtained by exploiting the diversity in coverage offered by many cellular operators, different technology networks (e.g. GPRS, CDMA), and diverse wireless channels.
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paper_title: The Design of Mobile Concurrent Multipath Transfer in Multihomed Wireless Mobile Networks

paper_content:

As more and more devices are equipped with multiple network interfaces, the multihomed technology is becoming an important technology that can provide more reliable connection against the network failure and higher data transmission rate. Concurrent Multipath Transfer (CMT), which is based on SCTP, is devised for multihomed networks. CMT can transmit data over all paths to maximize the data transmission speed. One of the main concerns of CMT is the receiver buffer blocking issue, especially in multihomed wireless mobile networks. Receiver buffer blocking is mainly caused by lost data. In this paper, we propose mobile CMT (mCMT) over wireless networks to deal with the receiver buffer blocking caused by error loss and handoff loss. mCMT has the features of (i) path-oriented multistreaming, (ii) MIH-assisted handoff mechanism, in which MIH denotes Media Independent Handover and (iii) association resume. Path-oriented multistreaming can reduce the receiver buffer blocking caused by error loss. MIH-assisted a handoff can reduce the amount of packet loss during a handoff, which may lead to receiver buffer blocking. Moreover, mCMT introduces the concept of association resume to recover the disconnected association. Simulation results show that mCMT can reduce the effect of the receiver buffer blocking effectively for devices that have smaller buffer size.
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paper_title: DNIS: a middleware for dynamic multiple network interfaces scheduling

paper_content:

Wireless Intelligent Networks Center, Nile University, Smart Village, Egypt Many of today's mobile devices are equipped with multiple network interfaces that can be used to connect to the Internet, including Ethernet, WiFi, 3G, and Bluetooth. However, current operating systems, such as Windows and Linux, typically choose only one of the available network interfaces and assign all the traffic to it, even if more than one is connected to the Internet. This results in an obvious under utilization of the available bandwidth. Different bandwidth aggregation techniques suggested altering different layers of the TCP/IP stack which requires applying modifications on the client's stack and/or the cloud, which cannot be widely deployed easily. In this work, we present DNIS, a networking middleware that achieves bandwidth aggregation using per-TCP connection scheduling on different interfaces in a way that is transparent to both the user and the applications. DNIS is composed of two main components: (1) a parameter estimator that estimates the applications' characteristics and requirements as well as interfaces' properties; (2) a scheduler that uses the estimated parameters to assign different TCP connections to network interfaces. We present an implementation for DNIS for the Windows OS and show its performance for different scheduling algorithms. Our initial results show significant enhancement of the overall device's throughput, up to 54%, increasing resource utilization and enhancing the user's experience.
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paper_title: A User-level Socket Layer over Multiple Physical Network Interfaces

paper_content:

In this paper, we describe the design and implementation of an UDP-based socket that utilizes multiple network interface units connected through one or more networks. The socket is a middleware layer that provides abstract network APIs to hide low-level technical details from users. Parallel message fragmentation and reconstruction techniques and a reliable UDP-based protocol are introduced. The proposed socket layer transparently provides an expandable high bandwidth solution, fault tolerance, and load balancing for transmitting large messages over multiple networks. A prototype socket based on this model, called MuniSocket (Multiple Network Interface Socket), has been implemented and evaluated.
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paper_title: DBAS: A Deployable Bandwidth Aggregation System

paper_content:

The explosive increase in data demand coupled with the rapid deployment of various wireless access technologies have led to the increase of number of multi-homed or multi-interface enabled devices. Fully exploiting these interfaces has motivated researchers to propose numerous solutions that aggregate their available bandwidths to increase overall throughput and satisfy the end-user's growing data demand. These solutions, however, have faced a steep deployment barrier that we attempt to overcome in this paper. We propose a Deployable Bandwidth Aggregation System (DBAS) for multi- interface enabled devices. Our system does not introduce any intermediate hardware, modify current operating systems, modify socket implementations, nor require changes to current applications or legacy servers. The DBAS architecture is designed to automatically estimate the characteristics of applications and dynamically schedule various connections or packets to different interfaces. Since our main focus is deployability, we fully implement DBAS on the Windows operating system and evaluate various modes of operation. Our implementation and simulation results show that DBAS achieves up to more than double the throughput gains compared to current operating systems, while operating as an out-of-the- box standard Windows executable, highlighting its deployability.
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paper_title: GreenBag: Energy-Efficient Bandwidth Aggregation for Real-Time Streaming in Heterogeneous Mobile Wireless Networks

paper_content:

Modern mobile devices are equipped with multiple network interfaces, including 3G/LTE and WiFi. Bandwidth aggregation over LTE and WiFi links offers an attractive opportunity of supporting bandwidth-intensive services, such as high-quality video streaming, on mobile devices. However, achieving effective bandwidth aggregation in mobile environments raises several challenges related to deployment, link heterogeneity, network fluctuation, and energy consumption. We present GreenBag, an energy-efficient bandwidth aggregation middleware that supports real-time data-streaming services over asymmetric wireless links, requiring no modifications to the existing Internet infrastructure and servers. GreenBag employs several techniques, including medium load balancing, efficient segment management, and energy-aware mode control, to resolve such challenges. We implement a prototype of GreenBag on Android-based mobile devices which hosts, to the best knowledge of the authors, the first LTE-enabled bandwidth aggregation prototype for energy-efficient real-time video streaming. Our experiment results in both emulated and real-world environments show that GreenBag not only achieves good bandwidth aggregation to provide QoS in bandwidth-scarce environments but also efficiently saves energy on mobile devices. Moreover, energy-aware GreenBag can minimize video interruption while consuming 14-25% less energy than the non-energy-aware counterpart in real-world experiments.
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paper_title: Intentional networking: opportunistic exploitation of mobile network diversity

paper_content:

Mobile devices face a diverse and dynamic set of networking options. Using those options to the fullest requires knowledge of application intent. This paper describes Intentional Networking, a simple but powerful mechanism for handling network diversity. Applications supply a declarative label for network transmissions, and the system matches transmissions to the most appropriate network. The system may also defer and re-order opportunistic transmissions subject to application-supplied mutual exclusion and ordering constraints. We have modified three applications to use Intentional Networking: BlueFS, a distributed file system for pervasive computing, Mozilla's Thunderbird e-mail client, and a vehicular participatory sensing application. We evaluated the performance of these applications using measurements obtained by driving a vehicle through WiFi and cellular 3G network coverage. Compared to an idealized solution that makes optimal use of all aggregated available networks but that lacks knowledge of application intent, Intentional Networking improves the latency of interactive messages from 48% to 13x, while adding no more than 7% throughput overhead.
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paper_title: INTELiCON: A Framework for the Simultaneous Utilization of Multiple Interfaces and its Application on TCP

paper_content:

Widespread deployment of Wi-Fi together with 3G upgrades to cellular networks is rapidly creating areas where multiple wireless IP technologies will coexist. WiMAX will further contribute to this phenomenon. The ability to use diverse access technologies simultaneously creates opportunities to improve application service quality and reliability. In this paper, we present an intelligent connectivity framework (INTELiCON) that allows devices to exploit access diversity in new ways. INTELiCON provides a modular, flexible platform for discovering, selecting, executing and evaluating the most appropriate transmission strategies over multiple interfaces while maintaining transparency to both the application and the link layers. We present the architectural characteristics of the INTELiCON framework and describe a prototype proof-of-concept implementation. Indicatively, we show how the framework exploits access diversity to improve TCP-based transmission despite limited resources and unreliable links.
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paper_title: A novel mechanism for data streaming across multiple IP links for improving throughput and reliability in mobile environments

paper_content:

With ubiquitous computing and network access, multiple network conduits are becoming available to mobile as well as static hosts. Selection of the preferred mode of data transfer is a dynamic optimization problem depending on the type of application, its bandwidth/latency/jitter requirements, current network status, cost, power consumption, battery life, and so on. Furthermore, since wireless bandwidth is likely to remain a scarce resource, we foresee scenarios wherein mobile hosts require simultaneous data transfer across multiple IP interfaces to obtain higher overall bandwidth. We present a brief overview of related work identifying schemes that might be applicable to the problem, along with their feasibility, and pros and cons. We then propose a new mechanism to aggregate the bandwidth of multiple IP links by splitting a data flow across multiple network interfaces at the IP level. Our method is transparent to transport (TCP/UDP) and higher layers. We have analyzed the performance characteristics of the aggregation scheme and demonstrated significant gain when the links being aggregated have similar bandwidth and latency. The use of multiple interfaces also enhances reliability. Our analysis identifies the conditions under which the proposed scheme, or any other scheme that stripes a single TCP connection across multiple IP links, can be used to enhance throughput. Several interesting directions for future work have also been identified.
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paper_title: cmpSCTP: An Extension of SCTP to Support Concurrent Multi-Path Transfer

paper_content:

This paper introduced cmpSCTP, a transport layer solution for concurrent multi-path transfer that modifies the standard Stream Control Transmission Protocol (SCTP). The cmpSCTP aims at exploiting SCTP's multi-homing capability by selecting several best paths among multiple available network interfaces to improve data transfer rate to the same multi-homed device. Through the use of path monitoring and packet allotment techniques, cmpSCTP tries to transmit given amount of packets at corresponding path as its ability. At the same time, cmpSCTP updates the transmission strategy based on the real-time information of all of paths. Using cmpSCTP's flexible path management capability, we may switch the flow between multiple paths automatically to realize seamless path handover. Extensive simulations under different scenarios using OPNET verified that cmpSCTP can effectively enhance transmission efficiency and highlighted the superiority of cmpSCTP against the other SCTP's extension implementations under performance indexes such as throughput, handover latency, packet delay, and packet loss.
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paper_title: OSCAR: A Collaborative Bandwidth Aggregation System

paper_content:

The exponential increase in mobile data demand, coupled with growing user expectation to be connected in all places at all times, have introduced novel challenges for researchers to address. Fortunately, the wide spread deployment of various network technologies and the increased adoption of multi-interface enabled devices have enabled researchers to develop solutions for those challenges. Such solutions aim to exploit available interfaces on such devices in both solitary and collaborative forms. These solutions, however, have faced a steep deployment barrier. ::: In this paper, we present OSCAR, a multi-objective, incentive-based, collaborative, and deployable bandwidth aggregation system. We present the OSCAR architecture that does not introduce any intermediate hardware nor require changes to current applications or legacy servers. The OSCAR architecture is designed to automatically estimate the system's context, dynamically schedule various connections and/or packets to different interfaces, be backwards compatible with the current Internet architecture, and provide the user with incentives for collaboration. We also formulate the OSCAR scheduler as a multi-objective, multi-modal scheduler that maximizes system throughput while minimizing energy consumption or financial cost. We evaluate OSCAR via implementation on Linux, as well as via simulation, and compare our results to the current optimal achievable throughput, cost, and energy consumption. Our evaluation shows that, in the throughput maximization mode, we provide up to 150% enhancement in throughput compared to current operating systems, without any changes to legacy servers. Moreover, this performance gain further increases with the availability of connection resume-supporting, or OSCAR-enabled servers, reaching the maximum achievable upper-bound throughput.
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paper_title: Bandwidth aggregation with SCTP

paper_content:

We present a number of modifications to the stream control transmission protocol (SCTP) recently adopted by IETF; they allow bandwidth aggregation over the multiple interfaces of a host. We show that it is possible to implement a number of algorithms for bandwidth aggregation, with only a small number of modifications to the basic SCTP. Our simulation results clearly depict the efficiency of our approach in terms of bandwidth utilization. Furthermore, we implement and evaluate a mechanism for identifying bottlenecks that are shared by flows from the same aggregate connection. Our purpose is to show that SCTP is a good candidate for building a practical protocol for bandwidth aggregation that is fair and supportive of TCP.
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paper_title: Feasibility considerations of multipath TCP in dealing with big data application

paper_content:

In this paper we present an idea to handle big data in a better way. We consider Multipath TCP (MPTCP) to use all available paths simultaneously. MPTCP is a tailored form of TCP which aspire to improve throughput by sharing available resources smartly and fairly. The key concentration of this paper is to analyze the benefit of MPTCP over single path TCP for bandwidth and time sensitive applications as well as big data application. Our simulation shows that MPTCP can higher goodput by bandwidth aggregation, Couple Congestion Control(CCC) provide better throughput without being unfair to other legacy TCP flows and also portray that large receive buffer causes performance enhancement for relatively large RTT link. As a result, MPTCP can be a enormous addition in contrast with single path TCP in dealing with big data application.
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paper_title: A Network Layer Approach to Enable TCP over Multiple Interfaces

paper_content:

The mobile Internet is set to become ubiquitous with the deployment of various wireless technologies. When heterogeneous wireless networks overlap in coverage, a mobile terminal can potentially use multiple wireless interfaces simultaneously. In this paper, we motivate the advantages of simultaneous use of multiple interfaces and present a network layer architecture that supports diverse multi-access services. Our main focus is on one such service provided by the architecture: Bandwidth Aggregation (BAG), specifically for TCP applications.While aggregating bandwidth across multiple interfaces can improve raw throughput, it introduces challenges in the form of packet reordering for TCP applications. When packets are reordered, TCP misinterprets the duplicate ACKS received as indicative of packet loss and invokes congestion control. This can significantly lower TCP throughput and counter any gains that can be had through bandwidth aggregation. To improve overall performance of TCP, we take a two-pronged approach: (1) We propose a scheduling algorithm that partitions traffic onto the different paths (corresponding to each interface) such that reordering is minimized. The algorithm estimates available bandwidth and thereby minimizes reordering by sending packet pairs on the path that introduces the least amount of delay. (2) A buffer management policy is introduced at the client to hide any residual reordering from TCP. We show through simulations that our network-layer approach can achieve good bandwidth aggregation under a variety of network conditions.
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paper_title: G-DBAS: A green and deployable bandwidth aggregation system

paper_content:

The widespread deployment of varying networking technologies, coupled with the exponential increase in end-user data demand, have all led to the proliferation of multi-homed or multi-interface enabled devices. To date, these interfaces are mainly utilized one at a time based on network availability, cost, and user-choice. Researchers have recently focused on leveraging these interfaces simultaneously by proposing solutions to aggregate their bandwidths in order to ultimately increase throughput and satisfy the end-user's growing demand on data. These solutions, however, have faced a steep deployment barrier due to various system design choices and heavy demand on energy. In this paper, we propose a novel Green and Deployable Bandwidth Aggregation System (G-DBAS) for multiple interface enabled devices. G-DBAS addresses a set of challenges including automatically estimating the characteristics of applications and scheduling various connections to different interfaces along with meeting different energy consumption goals set by users. We fully implement G-DBAS on the Windows OS and evaluate various scheduling strategies that we propose. Our implementation and simulation results show that G-DBAS can achieve the user energy-throughput goals while operating as an out-of-the-box standard Windows executable, highlighting its deployability and ease of use.
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paper_title: Design and implementation of a socket-level bandwidth aggregation mechanism for wireless networks

paper_content:

This paper proposes a mechanism to aggregate bandwidth of multiple network interfaces on a computer. Recently one single computer entails multiple different wireless network interfaces, such as IEEE 802.11a/b/g/n, Bluetooth, WiMAX, and so on. They can be combined, and we can aquire broad bandwidth. We designed and developed a Socket-level Bandwidth Aggregation Mechanism (SBAM). SBAM can aggregate multiple interfaces on a computer to offer broad bandwidth. In addition, implementation in socket layer causes easy deployment and adaptation to existing environment. We evaluated SBAM under actual wireless network environments. SBAM offers broad bandwidth by utilizing various wireless devices on a computer while it avoids modification to existing environment.
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paper_title: MOTA: engineering an operator agnostic mobile service

paper_content:

There are two emerging trends in the mobile data world. First, mobile data is exploding at a rapid rate with analysts predicting 25-50X growth by the year 2015. The second trend is that users are demanding greater degree of flexibility in selecting their operators at fine timescales. Across Asia, dual-SIM phones have become popular, while Apple is rumored to be designing a Universal SIM that will allow iPhone users to toggle between different operators. This latter trend points towards an impending disruption in wireless service models which could also be the need of the hour from the spectrum shortage perspective. This points towards a new service model where users can choose an operator based on application needs. However, if users make this choice greedily without network assistance, it can exacerbate spectrum scarcity and degrade user experience. In this work, we consider user devices with multiple network interfaces (3G, LTE etc.) that can be simultaneously active and each running multiple applications. We propose the MOTA service model to enable users to associate each interface with the operator of choice at fine time scales. Under the MOTA service model, through concise signalling information, operators provide information about their own network, so that each user can (i) choose a suitable operator for each interface, and (ii) choose an interface for each active application. We make the following contributions in this paper. First, we propose concise network signalling that assists users to make informed choices even under mobility. Second, we develop user-choice algorithms that maximize a suitable notion of user satisfaction while using spectrum resources efficiently. Third, we perform extensive evaluation over actual base station deployment in a city coupled with real signal propagation maps. Our results with two operators show that, MOTA service model provides capacity gain in the range 2.5-4X over the current existing service model. Finally, we argue that our solution is practically implementable by combining appropriate IEEE standards and IETF proposals.
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paper_title: COBA: Concurrent Bandwidth Aggregation - A Case Study in Parallel Wireless Communications

paper_content:

Parallel Wireless Communications is an emerging area of research that enables mobile clients to access and utilize multiple wireless networks concurrently. This paper explores concurrent bandwidth aggregation techniques to enable parallel wireless communications on mobile devices. Concurrent aggregation can be performed using wireless modems on one device or cooperatively across devices within wireless proximity of each other.. The aggregation can be achieved on the application-layer, transport layer like MultipathTCP, or on layers below IP such as the RLC layer. These schemes are compared. In general, aggregation on the lower layer is closer to the client device and easier to adapt to the varying channel and loading conditions. However, lower layer aggregation needs more changes to wireless access stratum infrastructure. Aggregation above the IP layer is simpler to implement. A feasibility study of MultipathTCP aggregation over multiple WWANs is presented. The aggregation scheme on the RLC layer in evolved HSDPA is also presented, including protocol design and performance evaluation.
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paper_title: OPERETTA: An optimal energy efficient bandwidth aggregation system

paper_content:

The widespread deployment of varying networking technologies, coupled with the exponential increase in end-user data demand, have led to the proliferation of multi-homed or multi-interface enabled devices. To date, these interfaces are mainly utilized one at a time based on network availability, cost, and user-choice. While researchers have focused on simultaneously leveraging these interfaces by aggregating their bandwidths, these solutions however, have faced a steep deployment barrier. In this paper, we propose a novel optimal, energy-efficient, and deployable bandwidth aggregation system (OPERETTA) for multiple interface enabled devices. OPERETTA satisfies three goals: achieving a user defined throughput level with optimal energy consumption over multiple interfaces, deployability without changes to current legacy servers, and leveraging incremental deployment to achieve increased performance gains. We present the OPERETTA architecture and formulate the optimal scheduling problem as a mixed integer programming problem yielding an efficient solution. We evaluate OPERETTA via implementation on the the Windows OS, and further verify our results with simulations on NS2. Our evaluation shows the tradeoffs between the energy and throughput goals. Furthermore, with no modifications to current legacy servers, OPERETTA achieves throughput gains up to 150% compared to current operating systems with the same energy consumption. In addition, with as few as 25% of the servers becoming OPERETTA enabled, OPERETTA performance reaches the throughput upper bound, highlighting its incremental deployment and performance gains.
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paper_title: Deployable multipath communication scheme with sufficient performance data distribution method

paper_content:

Multi-homed environments are increasingly common, especially for mobile users. And several multipath communication techniques have been proposed, such as multipath TCP communication techniques. Multipath TCP techniques have potential to fully utilize multiple paths, but, these methods have difficulties in implementation and deployment, because users need to modify their applications or operating system or both. In this paper, we propose simple multipath communication technique, which we call Arrival-Time matching Load-Balancing (ATLB). ATLB is designed to be easily implementable on several environments. Besides, we also introduce overlay network approach which implicitly provides parallel data transfer scheme to users. The ATLB continuously calculates transmission delays of each path, including TCP queuing delay at a sender and network delay, and then sends a data segment through the TCP connection with the lowest delay. Simulation results show that ATLB realizes sufficient performance even in heterogeneous environments where the quality of paths differs. Measurement results over our wireless LAN test-bed system suggest that ATLB can fully utilize the aggregate available bandwidth over unstable multiple wireless links.
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paper_title: MAR: a commuter router infrastructure for the mobile Internet

paper_content:

We introduce MAR, a commuter mobile access router infrastructure that exploits wireless diversity (e.g. channel diversity, network diversity, and technology diversity) to provide improved data performance for wireless data users. Our system design stems from the observation that rather than choosing a single wireless service provider (e.g. Sprint, AT&T, BT, Vodafone), a single technology (e.g. GPRS, UMTS, CDMA, 802.11), or a single wireless channel, users can obtain significant benefits by using the multiplicity of choices available. MAR is a wireless multi-homed device that can be placed in moving vehicles (e.g. car, bus, train) to enable high-speed data access. MAR dynamically instantiates new channels based on traffic demand, aggregates the bandwidth and dynamically shifts load from poor quality to better quality channels. MAR, thus, provides a faster, more stable, and reliable communication channel to mobile users.We have implemented and tested the MAR system in our testbed which spans the networks of three different cellular providers. Through our experiments we have performed a detailed evaluation to quantify the benefits of MAR for different protocols and applications. For example, even in highly mobile environments, MAR, on average, improves the end-user experience of web-browsing and streaming applications by a factor of 2.8 and 4.4 respectively. Our results show that significant benefits can be obtained by exploiting the diversity in coverage offered by many cellular operators, different technology networks (e.g. GPRS, CDMA), and diverse wireless channels.
---
paper_title: DNIS: a middleware for dynamic multiple network interfaces scheduling

paper_content:

Wireless Intelligent Networks Center, Nile University, Smart Village, Egypt Many of today's mobile devices are equipped with multiple network interfaces that can be used to connect to the Internet, including Ethernet, WiFi, 3G, and Bluetooth. However, current operating systems, such as Windows and Linux, typically choose only one of the available network interfaces and assign all the traffic to it, even if more than one is connected to the Internet. This results in an obvious under utilization of the available bandwidth. Different bandwidth aggregation techniques suggested altering different layers of the TCP/IP stack which requires applying modifications on the client's stack and/or the cloud, which cannot be widely deployed easily. In this work, we present DNIS, a networking middleware that achieves bandwidth aggregation using per-TCP connection scheduling on different interfaces in a way that is transparent to both the user and the applications. DNIS is composed of two main components: (1) a parameter estimator that estimates the applications' characteristics and requirements as well as interfaces' properties; (2) a scheduler that uses the estimated parameters to assign different TCP connections to network interfaces. We present an implementation for DNIS for the Windows OS and show its performance for different scheduling algorithms. Our initial results show significant enhancement of the overall device's throughput, up to 54%, increasing resource utilization and enhancing the user's experience.
---
paper_title: A User-level Socket Layer over Multiple Physical Network Interfaces

paper_content:

In this paper, we describe the design and implementation of an UDP-based socket that utilizes multiple network interface units connected through one or more networks. The socket is a middleware layer that provides abstract network APIs to hide low-level technical details from users. Parallel message fragmentation and reconstruction techniques and a reliable UDP-based protocol are introduced. The proposed socket layer transparently provides an expandable high bandwidth solution, fault tolerance, and load balancing for transmitting large messages over multiple networks. A prototype socket based on this model, called MuniSocket (Multiple Network Interface Socket), has been implemented and evaluated.
---
paper_title: DBAS: A Deployable Bandwidth Aggregation System

paper_content:

The explosive increase in data demand coupled with the rapid deployment of various wireless access technologies have led to the increase of number of multi-homed or multi-interface enabled devices. Fully exploiting these interfaces has motivated researchers to propose numerous solutions that aggregate their available bandwidths to increase overall throughput and satisfy the end-user's growing data demand. These solutions, however, have faced a steep deployment barrier that we attempt to overcome in this paper. We propose a Deployable Bandwidth Aggregation System (DBAS) for multi- interface enabled devices. Our system does not introduce any intermediate hardware, modify current operating systems, modify socket implementations, nor require changes to current applications or legacy servers. The DBAS architecture is designed to automatically estimate the characteristics of applications and dynamically schedule various connections or packets to different interfaces. Since our main focus is deployability, we fully implement DBAS on the Windows operating system and evaluate various modes of operation. Our implementation and simulation results show that DBAS achieves up to more than double the throughput gains compared to current operating systems, while operating as an out-of-the- box standard Windows executable, highlighting its deployability.
---
paper_title: Improved data distribution for multipath TCP communication

paper_content:

Multi-homed environments are increasingly common, especially for mobile users. To efficiently utilize multiple access lines for single file transfer, multipath TCP communication methods have been proposed. A multipath TCP enables simultaneous distributed data transfer between two end-points on multiple TCP connections. However, these methods cannot fully utilize the available bandwidth of multiple paths because they do not properly consider the end-to-end delay of packet transmission, so out-of-order data arrival at a receiver causes a bottleneck in data sort operations. This problem is more severe in environments where the quality of each path is different or unstable, such as in wireless environments. To solve this problem, we propose a multipath TCP communication method that includes a data distribution method to enable in-order delivery at a receiver. We call this arrival-time matching load-balancing (ATLB). ATLB continuously calculates the delay of each path, including the TCP queuing delay at a sender and the network delay, and then sends a data segment through the TCP connection with the lowest end-to-end delay. Simulation results show that ATLB improves end-to-end throughput, especially in heterogeneous environments where the quality of paths differs. For example, ATLB enabled twice the throughput with the conventional multipath TCP. We also report performance evaluation results from our ATLB test bed system in a wireless network environment. Our ATLB test bed system was able to fully utilize the aggregate available bandwidth of unstable multiple wireless links.
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paper_title: Aggregating Bandwidth for Multihomed Mobile Collaborative Communities

paper_content:

Multihomed, mobile wireless computing and communication devices can spontaneously form communities to logically combine and share the bandwidth of each other's wide-area communication links using inverse multiplexing. But, membership in such a community can be highly dynamic, as devices and their associated WWAN links randomly join and leave the community. We identify the issues and trade-offs faced in designing a decentralized inverse multiplexing system in this challenging setting and determine precisely how heterogeneous WWAN links should be characterized and when they should be added to, or deleted from, the shared pool. We then propose methods of choosing the appropriate channels on which to assign newly arriving application flows. Using video traffic as a motivating example, we demonstrate how significant performance gains can be realized by adapting allocation of the shared WWAN channels to specific application requirements. Our simulation and experimentation results show that collaborative bandwidth aggregation systems are, indeed, a practical and compelling means of achieving high-speed Internet access for groups of wireless computing devices beyond the reach of public or private access points
---
paper_title: Intentional networking: opportunistic exploitation of mobile network diversity

paper_content:

Mobile devices face a diverse and dynamic set of networking options. Using those options to the fullest requires knowledge of application intent. This paper describes Intentional Networking, a simple but powerful mechanism for handling network diversity. Applications supply a declarative label for network transmissions, and the system matches transmissions to the most appropriate network. The system may also defer and re-order opportunistic transmissions subject to application-supplied mutual exclusion and ordering constraints. We have modified three applications to use Intentional Networking: BlueFS, a distributed file system for pervasive computing, Mozilla's Thunderbird e-mail client, and a vehicular participatory sensing application. We evaluated the performance of these applications using measurements obtained by driving a vehicle through WiFi and cellular 3G network coverage. Compared to an idealized solution that makes optimal use of all aggregated available networks but that lacks knowledge of application intent, Intentional Networking improves the latency of interactive messages from 48% to 13x, while adding no more than 7% throughput overhead.
---
paper_title: Collaborative Downloading for Multi-homed Wireless Devices

paper_content:

Mobile devices are increasingly equipped with multiple network interfaces: Wireless Local Area Network (WLAN) interfaces for local connectivity and Wireless Wide Area Network (WWAN) interfaces for wide-area connectivity. The WWAN typically provides much wider coverage but much lower speeds than the WLAN. To address this dichotomy, we consider collaborative downloading among mobile devices in close proximity. We demonstrate the potential benefits of such an approach and discuss the many challenges to realizing it in practice: incentivizing cooperation by adequately compensating nodes, effecting such cooperation via an efficient protocol, and facilitating it with a suitable user interface. We present our current thinking on these as we design a collaborative downloading system called COMBINE.
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paper_title: An incentive mechanism based on the Bayes Equilibrium of game theory in peer-to-peer networks

paper_content:

The free-riding problem is widely accepted to be retarding the deployment and growth of P2P networks. In order to solve this problem, we give a strict definition of the peer's contribution, utility and incentive reputation and model a P2P network with heterogeneous peers as an incomplete information static game. We use incentive reputation to incentivize peers to share their resources and provide services to others, for the services available to the peer are directly depend on its current incentive reputation. A peer can enhance its reputation by increasing its contribution. Experimental results show that all peers optimize their strategy to the Bayes Equilibrium in which the utility of each peer's is maximized and the free-riding problem is minimized, then the whole network serves at a high quality.
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paper_title: QoS-oriented MPTCP Extensions for Multimedia Multi-homed Systems

paper_content:

The increasing number of interfaces using different access technologies in modern devices gives opportunities for enhancing the Quality of Service (QoS) delivered to multimedia and interactive data transfers involved in distributed applications. In the current Internet, the presence of "middleboxes" such as Network Address Translators (NAT) or firewalls hardly lets applications use any Transport protocol but the well-known Transmission Control Protocol (TCP). Currently under standardization at the IETF, the new Multipath-TCP (MPTCP) protocol uses several TCP flows to make use of the multiple interfaces available on the end terminals, thus improving both network availability and QoS, still being capable to cross over middle boxes. Although originally being fully reliable and fully ordered, its two sub-layers architecture gives opportunity to use QoS techniques over fully reliable paths. This paper studies the QoS benefits induced by the implementation of the "partial reliability" concept in MPTCP for interactive video applications. Two different mechanisms are experimented with the aim to enhance global quality of video transmission over paths close to 3G networks characteristics. The Internet Engineering Task Force (IETF) MPTCP working group's ns-2 implementation is used for the experimentations. The Evalvid toolkit over ns-2 is used to measure the QoS benefits expressed in terms of Peak Signal to Noise Ratio (PSNR).
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paper_title: MobiCent: a Credit-Based Incentive System for Disruption Tolerant Network

paper_content:

When Disruption Tolerant Network (DTN) is used in commercial environments, incentive mechanism should be employed to encourage cooperation among selfish mobile users. Key challenges in the design of an incentive scheme for DTN are that disconnections among nodes are the norm rather than exception and network topology is time varying. Thus, it is difficult to detect selfish actions that can be launched by mobile users or to pre-determine the routing path to be used. In this paper, we propose MobiCent, a credit-based incentive system for DTN. While MobiCent allows the underlying routing protocol to discover the most efficient paths, it is also incentive compatible. Therefore, using MobiCent, rational nodes will not purposely waste transfer opportunity or cheat by creating non-existing contacts to increase their rewards. MobiCent also provides different payment mechanisms to cater to client that wants to minimize either payment or data delivery delay.
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paper_title: A novel mechanism for data streaming across multiple IP links for improving throughput and reliability in mobile environments

paper_content:

With ubiquitous computing and network access, multiple network conduits are becoming available to mobile as well as static hosts. Selection of the preferred mode of data transfer is a dynamic optimization problem depending on the type of application, its bandwidth/latency/jitter requirements, current network status, cost, power consumption, battery life, and so on. Furthermore, since wireless bandwidth is likely to remain a scarce resource, we foresee scenarios wherein mobile hosts require simultaneous data transfer across multiple IP interfaces to obtain higher overall bandwidth. We present a brief overview of related work identifying schemes that might be applicable to the problem, along with their feasibility, and pros and cons. We then propose a new mechanism to aggregate the bandwidth of multiple IP links by splitting a data flow across multiple network interfaces at the IP level. Our method is transparent to transport (TCP/UDP) and higher layers. We have analyzed the performance characteristics of the aggregation scheme and demonstrated significant gain when the links being aggregated have similar bandwidth and latency. The use of multiple interfaces also enhances reliability. Our analysis identifies the conditions under which the proposed scheme, or any other scheme that stripes a single TCP connection across multiple IP links, can be used to enhance throughput. Several interesting directions for future work have also been identified.
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paper_title: OSCAR: A Collaborative Bandwidth Aggregation System

paper_content:

The exponential increase in mobile data demand, coupled with growing user expectation to be connected in all places at all times, have introduced novel challenges for researchers to address. Fortunately, the wide spread deployment of various network technologies and the increased adoption of multi-interface enabled devices have enabled researchers to develop solutions for those challenges. Such solutions aim to exploit available interfaces on such devices in both solitary and collaborative forms. These solutions, however, have faced a steep deployment barrier. ::: In this paper, we present OSCAR, a multi-objective, incentive-based, collaborative, and deployable bandwidth aggregation system. We present the OSCAR architecture that does not introduce any intermediate hardware nor require changes to current applications or legacy servers. The OSCAR architecture is designed to automatically estimate the system's context, dynamically schedule various connections and/or packets to different interfaces, be backwards compatible with the current Internet architecture, and provide the user with incentives for collaboration. We also formulate the OSCAR scheduler as a multi-objective, multi-modal scheduler that maximizes system throughput while minimizing energy consumption or financial cost. We evaluate OSCAR via implementation on Linux, as well as via simulation, and compare our results to the current optimal achievable throughput, cost, and energy consumption. Our evaluation shows that, in the throughput maximization mode, we provide up to 150% enhancement in throughput compared to current operating systems, without any changes to legacy servers. Moreover, this performance gain further increases with the availability of connection resume-supporting, or OSCAR-enabled servers, reaching the maximum achievable upper-bound throughput.
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paper_title: Multi-Path Load Balancing in Transport Layer

paper_content:

In this paper, we propose an extension to current TCP protocol named concurrent TCP (cTCP), which can improve throughput of connections through balancing traffic load on multiple end-to-end paths. We keep the single-sliding-window architecture of TCP untouched for compatibility reasons. The two core components of the design are a packet scheduling switch that balances load among paths, and a duplicated acknowledgement classifier that handles packet reordering. We implemented our protocol in FreeBSD kernel and compared the performance of cTCP with theoretical results. Experiment outcomes show that throughputs of our protocol are close to the ideal values.
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paper_title: A Game Theory Based Reputation Mechanism to Incentivize Cooperation in Wireless Ad Hoc Networks

paper_content:

In wireless ad hoc networks one way to incentivize nodes to forward other nodes' packets is through the use of reputation mechanisms, where cooperation is induced by the threat of partial or total network disconnection if a node acts selfishly. The problem is that packet collisions and interference may make cooperative nodes appear selfish sometimes, generating unnecessary and unwanted punishments. With the use of a simple network model we first study the performance of some proposed reputation strategies and then present a new mechanism called DARWIN (Distributed and Adaptive Reputation mechanism for Wireless ad hoc Networks), where we try to avoid retaliation situations after a node is falsely perceived as selfish to help restore cooperation quickly. Using game theory, we prove that our mechanism is robust to imperfect measurements, is collusion-resistant and can achieve full cooperation among nodes. Simulations are presented to complement our theoretical analysis and evaluate the performance of our algorithm compared to other proposed reputation strategies.
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paper_title: Reducing Congestion Effects in Wireless Networks by Multipath Routing

paper_content:

We propose a solution to improve fairness and increase throughput in wireless networks with location information. Our approach consists of a multipath routing protocol, biased geographical routing (BGR), and two congestion control algorithms, in-network packet scatter (IPS) and end-to-end packet scatter (EPS), which leverage BGR to avoid the congested areas of the network. BGR achieves good performance while incurring a communication overhead of just 1 byte per data packet, and has a computational complexity similar to greedy geographic routing. IPS alleviates transient congestion by splitting traffic immediately before the congested areas. In contrast, EPS alleviates long term congestion by splitting the flow at the source, and performing rate control. EPS selects the paths dynamically, and uses a less aggressive congestion control mechanism on non-greedy paths to improve energy efficiency. Simulation and experimental results show that our solution achieves its objectives. Extensive ns-2 simulations show that our solution improves both fairness and throughput as compared to single path greedy routing. Our solution reduces the variance of throughput across all flows by 35%, reduction which is mainly achieved by increasing throughput of long-range flows with around 70%. Furthermore, overall network throughput increases by approximately 10% Experimental results on a 50- node testbed are consistent with our simulation results, suggesting that BGR is effective in practice.
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paper_title: Network coding based reliable disjoint and braided multipath routing for sensor networks

paper_content:

This paper presents network coding based reliable disjoint and braided multipath routing (NC-RMR ) for sensor networks, which forms multipath by hop-by-hop method and only maintains local path information of each node without establishing end-to-end paths. Neighbors of each local node are divided into groups according to their hops to sink nodes to improve the network load balancing. For further performance improvement of NC-RMR with disjoint multipath model, local nodes select their own backup nodes in neighbor nodes to form additional logical paths, which implement a braided multipath model. Security advantages of NC-RMR with multipath and network coding mechanisms are analyzed. Analytical and simulation results prove that braided multipath routing model has better performance over disjoint model, and NC-RMR protocol can reduce the required number of transmission paths, ensure load balance of sensor network system, reduce the energy consumption of nodes.
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paper_title: Redundant source routing for real-time services in ad hoc networks

paper_content:

Quality-of-service in ad hoc networks is becoming more important with progress of the ad hoc networking research and development. In this paper, we proposed a new routing protocol named RSR for ad hoc networks. RSR is one type of redundant dispersity routing protocol. Through the judicious use of packet replication in RSR, the performance of network applications in ad hoc network is significantly enhanced. This enhancement is of great meaning for mission-critical applications with stringent delay requirement, especially in networks with frequently changing topologies. Both TCP and UDP traffic are used to evaluate the performance of RSR using DSR as the benchmark. The simulation results show that RSR improves the packet drop rate and end-to-end delay for UDP traffic and improves the end-to-end goodput for TCP traffic. RSR is a good candidate for QoS routing and fault-tolerant real-time services in ad hoc networks
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paper_title: Survey of multipath routing protocols for mobile ad hoc networks

paper_content:

This survey investigates multipath routing protocols for mobile ad hoc networks (MANETs). The main objectives of multipath routing protocols are to provide reliable communication and to ensure load balancing as well as to improve quality of service (QoS) of MANETs. These multipath protocols are broadly classified into five categories based on their major goals. The goals are to improve delay, provide reliability, reduce overhead, maximize network life and support hybrid routing. Multipath routing protocols address issues such as multiple paths discovery and maintaining these paths. Issues, objectives, performances, advantages and disadvantages of these protocols are investigated and summarized. A checklist is provided as a guideline so that a network designer can choose an appropriate multipath routing protocol to meet the network's application objectives.
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paper_title: TCP performance over multipath routing in mobile ad hoc networks

paper_content:

In this paper, we investigate TCP performance over a multipath routing protocol. Multipath routing can improve the path availability in mobile environment. Thus, it has a great potential to improve TCP performance in ad hoc networks under mobility. Previous research on multipath routing mostly used UDP traffic for performance evaluation. When TCP is used, we find that most times, using multiple paths simultaneously may actually degrade TCP performance. This is partly due to frequent out-of-order packet delivery via different paths. We then test another multipath routing strategy called backup path routing. Under the backup path routing scheme, TCP is able to gain improvements against mobility. We then further study related issues to backup path routing, which can affect TCP performance. Some important discoveries are reported in the paper and simulation results show that by careful selection of the multipath routing strategies, we can improve TCP performance by more than 30% even under very high mobility.
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paper_title: Multipath Fresnel zone routing for wireless ad hoc networks

paper_content:

This paper describes a novel multipath routing algorithm, Fresnel zone routing (FZR), for wireless ad hoc networks. First, the concept of Fresnel zones in an ad hoc network is introduced to classify intermediate nodes according to their capacity and efficiency for forwarding traffic. Second, multiple paths via different Fresnel zones are constructed efficiently using a hybrid of proactive and on-demand approaches. By dispersing traffic into multiple zones according to network load and congestion conditions, FZR can alleviate congestion at intermediate nodes and achieve better transport layer throughput. The operations of FZR are implemented and verified with discrete-event simulation models. Simulation experiments show that FZR can provide significant performance improvement over existing unipath and multipath routing protocols for both TCP and UDP traffic.
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paper_title: Disk System Architectures for High Performance Computing

paper_content:

Because of the mismatch between I/O and CPU speeds, high-performance computers have long been forced to confront the fundamental I/O bottleneck. As processing power and memory size continue to grow rapidly for micro- and minicomputers, they too will become I/O limited. A number of hardware and software approaches such as parallel read-out disks, expanded storage (for example, solid-state disks), and disk striping, have been used to increase I/O bandwidth and thus narrow the CPU-I/O performance gap. In addition, new developments driven by advances in small-diameter (5.25-in and 3.5-in) disk drives, promise very high I/O bandwidth if large numbers of devices can be organized into arrays of disks. In this paper we review the state of the art in disk devices and I/O controllers, and will describe new approaches for very high-performance I/O based on redundant arrays of inexpensive disks (RAIDs).
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paper_title: Striping within the network subsystem

paper_content:

Striping is a general architectural technique for the, transparent aggregation of multiple, functionally similar, resources to obtain higher performance. This article establishes a precise terminology for discussing striping and striping techniques, differentiates striping from the more general architectural technique of multiplexing, and outlines the major uses and trade-offs associated with the technique within the network subsystem. It presents a set of criteria for evaluating network striping and a case study of striping within a typical high performance network stack consisting of TCP/IP over ATM/SONET. IT also includes a set of "rules of thumb" for the inclusion of striping within the network subsystem. An appendix describes the trace driven simulation used to support the case study. >
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paper_title: Dead zone penetration protocol for cognitive radio networks

paper_content:

Current routing protocols for cognitive radio networks are severely affected by the frequent activity of primary users. Nodes that are in the interference range of an appearing primary user are not allowed to transmit, and therefore existing routes which utilize such nodes are obliged to undergo a route maintenance phase. This naturally provides other routes to the destination that may incur extra delay or increase packet queuing overhead. In this work, a novel route maintenance protocol is proposed that allows existing routes to endure the event of primary user presence by forming cooperative links between neighboring nodes and nulling out transmission at the primary receiver using cooperative beamforming. Our proposed protocol can be used in conjunction with any of the existing routing protocols, thus achieving modularity. Extensive simulations are done which prove that our proposed protocol outperforms existing route maintenance techniques in terms of end-to-end delay and loss ratio, with minimal incurred overhead.
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paper_title: Augmenting mobile 3G using WiFi

paper_content:

We investigate if WiFi access can be used to augment 3G capacity in mobile environments. We rst conduct a detailed study of 3G and WiFi access from moving vehicles, in three different cities. We find that the average 3G and WiFi availability across the cities is 87% and 11%, respectively. WiFi throughput is lower than 3G through-put, and WiFi loss rates are higher. We then design a system, called Wiffler, to augments mobile 3G capacity. It uses two key ideas leveraging delay tolerance and fast switching -- to overcome the poor availability and performance of WiFi. For delay tolerant applications, Wiffler uses a simple model of the environment to predict WiFi connectivity. It uses these predictions to delays transfers to offload more data on WiFi, but only if delaying reduces 3G usage and the transfers can be completed within the application's tolerance threshold. For applications that are extremely sensitive to delay or loss (e.g., VoIP), Wiffler quickly switches to 3G if WiFi is unable to successfully transmit the packet within a small time window. We implement and deploy Wiffler in our vehicular testbed. Our experiments show that Wiffler significantly reduces 3G usage. For a realistic workload, the reduction is 45% for a delay tolerance of 60 seconds.
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paper_title: Wake on wireless: an event driven energy saving strategy for battery operated devices

paper_content:

The demand for an all-in-one phone with integrated personal information management and data access capabilities is beginning to accelerate. While personal digital assistants (PDAs) with built-in cellular, WiFi, and Voice-Over-IP technologies have the ability to serve these needs in a single package, the rate at which energy is consumed by PDA-based phones is very high. Thus, these devices can quickly drain their own batteries and become useless to their owner.In this paper, we introduce a technique to increase the battery lifetime of a PDA-based phone by reducing its idle power, the power a device consumes in a "standby" state. To reduce the idle power, we essentially shut down the device and its wireless network card when the device is not being used---the device is powered only when an incoming call is received. Using this technique, we can increase the battery lifetime by up to 115%.In this paper, we describe the design of our "wake-on-wireless" energy-saving strategy and the prototype device we implemented. To evaluate our technique, we compare it with alternative approaches. Our results show that our technique can provide a significant lifetime improvement over other technologies.
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paper_title: Routing in multi-radio, multi-hop wireless mesh networks

paper_content:

We present a new metric for routing in multi-radio, multi-hop wireless networks. We focus on wireless networks with stationary nodes, such as community wireless networks.The goal of the metric is to choose a high-throughput path between a source and a destination. Our metric assigns weights to individual links based on the Expected Transmission Time (ETT) of a packet over the link. The ETT is a function of the loss rate and the bandwidth of the link. The individual link weights are combined into a path metric called Weighted Cumulative ETT (WCETT) that explicitly accounts for the interference among links that use the same channel. The WCETT metric is incorporated into a routing protocol that we call Multi-Radio Link-Quality Source Routing.We studied the performance of our metric by implementing it in a wireless testbed consisting of 23 nodes, each equipped with two 802.11 wireless cards. We find that in a multi-radio environment, our metric significantly outperforms previously-proposed routing metrics by making judicious use of the second radio.
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paper_title: Reconsidering wireless systems with multiple radios

paper_content:

The tremendous popularity of wireless systems in recent years has led to the commoditization of RF transceivers (radios) whose prices have fallen dramatically. The lower cost allows us to consider using two or more radios in the same device. Given this, we argue that wireless systems that use multiple radios in a collaborative manner dramatically improve system performance and functionality over the traditional single radio wireless systems that are popular today. In this context, we revisit some standard problems in wireless networking, including energy management, capacity enhancement, mobility management, channel failure recovery, and last-hop packet scheduling. We show that a systems approach can alleviate many of the performance and robustness issues prevalent in current wireless LAN systems. We explore the implications of the multi-radio approach on software and hardware design, as well as on algorithmic and protocol research issues. We identify three key design guidelines for constructing multi-radio systems and present results from two systems that we have built. Our experience supports our position that a multi-radio platform offers significant ben-efits for wireless systems.
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paper_title: Dynamic open spectrum sharing MAC protocol for wireless ad hoc networks

paper_content:

In legacy wireless communication systems, spectrum allocation is static, resulting in extremely low spectrum utilization. On the other hand, there is little spectrum left for allocation to an increasing number of emerging wireless applications. A promising approach to solving this paradox is opening up most of the spectrum for unlicensed spectrum users in ways that co-exist with legacy users. Following this direction, this paper proposes the dynamic open spectrum sharing (DOSS) MAC protocol. This protocol allows nodes to adaptively select an arbitrary spectrum for the incipient communication subject to spectrum availability. It offers real-time dynamic spectrum allocation and high spectrum utilization without relying on any infrastructure. It also coexists with legacy wireless applications, while avoiding the hidden and exposed terminal problems. We conduct theoretical analysis of the protocol, and study its performance via simulations. In addition, we covers the radio receiver design
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paper_title: Personal Area Networks: Bluetooth or IEEE 802.11?

paper_content:

Interconnecting all our electronic devices we carry around, such as cellular phones, PDAs, and laptops, with wireless links requires a cheap, low-power radio technology that still delivers good performance. In this context, the Bluetooth wireless technology was developed to meet the requirements introduced by these personal area networks (PANs). However, today we see a widespread deployment of wireless local area network (WLAN) radios (primarily IEEE 802.11b) also in small devices, such as PDAs. This paper will compare the PAN capabilities of a Bluetooth-based system with an IEEE 802.11b-based system. In order to focus the comparison on link and networking functionality, the IEEE 802.11b radio is assumed to be operating at the same power level as the Bluetooth radio (i.e., assuming a 0 dBm radio). Results are obtained by means of simulations in which throughput and delay are measured for multihop and overlaid PANs. Estimations on power usage are also given in the simulations. The results indicate that as the number of PANs increases, the Bluetooth-based PANs basically maintain the same bandwidth per PAN, while the corresponding IEEE 802.11-based PANs suffer significantly from the increased co-channel interference. However, for cases with a few co-channel-interfering PANs (2-3 PANs hosting about 10-15 nodes), the IEEE 802.11b-based PANs offer a higher bandwidth per user than the corresponding Bluetooth PANs, which corresponds to the difference in link bandwidth between the two systems. At high interference levels, the Bluetooth PAN offers a higher capacity than the IEEE 802.11 PAN. The latter also shows unfairness among TCP connections in the PAN at high loads. The energy efficiency, defined as successfully transmitted bits per energy unit, decreases sharply for IEEE 802.11 with increased number of PANs, while Bluetooth maintains a constant level. Packet delays are also shown to be more stable for the Bluetooth PAN than for the IEEE 802.11 PAN as the number of PANs increases.
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paper_title: An Energy-Efficient Architecture for DTN Throwboxes

paper_content:

Disruption Tolerant Networks rely on intermittent contacts between mobile nodes to deliver packets using store-carry-and-forward paradigm. The key to improving performance in DTNs is to engineer a greater number of transfer opportunities. We earlier proposed the use of throwbox nodes, which are stationary, battery powered nodes with storage and processing, to enhance the capacity of DTNs. However, the use of throwboxes without efficient power management is minimally effective. If the nodes are too liberal with their energy consumption, they will fail prematurely. However if they are too conservative, they may miss important transfer opportunities, hence increasing lifetime without improving performance. In this paper, we present a hardware and software architecture for energy efficient throwboxes in DTNs. We propose a hardware platform that uses a multi-tiered, multi-radio, scalable, solar powered platform. The throwbox employs an approximate heuristic for solving the NP-Hard problem of meeting an average power constraint while maximizing the number of bytes forwarded by it. We built and deployed prototype throwboxes in UMassDieselNet -a bus DTN testbed. Through extensive trace-driven simulations and prototype deployment we show that a single throwbox with a 270 cm2 solar panel can run perpetually while improving packet delivery by 37% and reducing message delivery latency by at least 10% in the network.
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paper_title: DSAP: a protocol for coordinated spectrum access

paper_content:

The continually increasing number of wireless devices operating in the unlicensed frequency bands makes the freely-available wireless spectrum a scarce commodity. Under such circumstances, efficient wireless spectrum management is necessary to minimize the effects of overcrowding and maximize quality of service. In this paper we present the design, implementation and evaluation of dynamic spectrum access protocol (DSAP), a centralized method for managing and coordinating spectrum access
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Title: Bandwidth Aggregation Techniques in Heterogeneous Multi-homed Devices: A Survey
Section 1: LAYER-DEPENDENT FEATURES
Description 1: This section discusses the various solutions for bandwidth aggregation implemented at different layers of the protocol stack, highlighting their unique challenges and features.

Section 2: Application Layer Solutions
Description 2: This part breaks down application layer solutions into hidden and non-transparent middlewares, discussing their respective advantages, deployment complexities, and examples.

Section 3: Transport Layer Solutions
Description 3: This section categorizes transport layer solutions into TCP extensions, SCTP-based solutions, and newly designed protocols, and discusses their congestion control mechanisms.

Section 4: Network Layer Solutions
Description 4: This section addresses network layer solutions that aim to maintain transport layer protocol functionalities while managing multiple network interfaces by modifying the network layer.

Section 5: MAC Layer Solutions
Description 5: This section covers the early techniques for bandwidth aggregation at the MAC layer, discussing solutions for direct connections and other approaches for various types of network media.

Section 6: LAYER-INDEPENDENT FEATURES
Description 6: This section outlines features shared by bandwidth aggregation solutions regardless of the implementation layer, including interface and application characteristics estimation, scheduling, and network support.

Section 7: Interface Characteristics Estimation
Description 7: This part details the techniques used by various solutions to estimate interface characteristics such as available bandwidth, delay, and energy consumption.

Section 8: Applications Characteristics Estimation
Description 8: This section discusses different approaches for understanding and estimating application requirements to inform better scheduling decisions.

Section 9: Scheduling
Description 9: This section explores different scheduling granularity and techniques used to distribute data across multiple interfaces to achieve optimal performance.

Section 10: Network Support and Communication Model
Description 10: This section details the client-server communication models adopted by bandwidth aggregation systems and their impact on the overall system performance.

Section 11: EVOLUTION AND CHALLENGES
Description 11: This section examines the evolution of bandwidth aggregation solutions over time and highlights ongoing challenges the research community needs to address.

Section 12: Evolution
Description 12: This part tracks the chronological development of solutions, focusing on their transitions across the protocol stack layers and changes in scheduling granularity.

Section 13: Challenges
Description 13: This section outlines current obstacles to the deployment of bandwidth aggregation solutions, such as deployability, use of middle-boxes, and enabling client collaboration.

Section 14: TANGENTIAL RESEARCH AREAS
Description 14: This section identifies related research areas, such as multi-path routing, resource aggregation in computer sub-systems, and the use of multiple network interfaces for non-bandwidth aggregation purposes.

Section 15: CONCLUSION
Description 15: This section summarizes the survey, presenting key insights into the solutions proposed for bandwidth aggregation in multi-homed devices, their evolution, and remaining research challenges.