The transport layer: tutorial and survey
---
paper_title: Host extensions for IP multicasting

paper_content:

This memo specifies the extensions required of a host implementation ::: of the Internet Protocol (IP) to support multicasting. Recommended ::: procedure for IP multicasting in the Internet. This RFC obsoletes RFCs ::: 998 and 1054. [STANDARDS-TRACK]
---
paper_title: A reliable multicast framework for light-weight sessions and application level framing

paper_content:

This paper describes SRM (Scalable Reliable Multicast), a reliable multicast framework for application level framing and light-weight sessions. The algorithms of this framework are efficient, robust, and scale well to both very large networks and very large sessions. The framework has been prototyped in wb, a distributed whiteboard application, and has been extensively tested on a global scale with sessions ranging from a few to more than 1000 participants. The paper describes the principles that have guided our design, including the IP multicast group delivery model, an end-to-end, receiver-based model of reliability, and the application level framing protocol model. As with unicast communications, the performance of a reliable multicast delivery algorithm depends on the underlying topology and operational environment. We investigate that dependence via analysis and simulation, and demonstrate an adaptive algorithm that uses the results of previous loss recovery events to adapt the control parameters used for future loss recovery. With the adaptive algorithm, our reliable multicast delivery algorithm provides good performance over a wide range of underlying topologies.
---
paper_title: Multicast Transport Protocol

paper_content:

This memo describes a protocol for reliable transport that utilizes ::: the multicast capability of applicable lower layer networking ::: architectures. The transport definition permits an arbitrary number of ::: transport providers to perform realtime collaborations without ::: requiring networking clients (aka, applications) to possess detailed ::: knowledge of the population or geographical dispersion of the ::: participating members. It is not network architectural specific, but ::: does implicitly require some form of multicasting (or broadcasting) at ::: the data link level, as well as some means of communicating that ::: capability up through the layers to the transport. This memo provides ::: information for the Internet community. It does not specify an ::: Internet standard.
---
paper_title: Requirements for Multicast Protocols

paper_content:

This memo discusses some of these unresolved issues, and provides a ::: high-level design for a new multicast transport protocol, group ::: address and membership authority, and modifications to existing ::: routing protocols. This memo provides information for the Internet ::: community. It does not specify an Internet standard.
---
paper_title: NETBLT: A bulk data transfer protocol

paper_content:

This document is a description of, and a specification for, the NETBLT ::: protocol. It is a revision of the specification published in RFC-969. ::: NETBLT (NETwork BLock Transfer) is a transport level protocol intended ::: for the rapid transfer of a large quantity of data between computers. ::: It provides a transfer that is reliable and flow controlled, and is ::: designed to provide maximum throughput over a wide variety of ::: networks. Although NETBLT currently runs on top of the Internet ::: Protocol (IP), it should be able to operate on top of any datagram ::: protocol similar in function to IP. This document is published for ::: discussion and comment, and does not constitute a standard. The ::: proposal may change and certain parts of the protocol have not yet ::: been specified; implementation of this document is therefore not ::: advised. Obsoletes RFC-969.
---
paper_title: The Delta-t transport protocol: features and experience

paper_content:

With the advent of new high performance networks and distribution systems there is renewed interest in transport protocol designs that can support both request/response and stream styles of communication. The author examines Delta-t, a transport protocol designed to meet such goals. Delta-t's main contribution is in the area of connection management, where it achieves hazard-free connection management without explicit packet exchanges. The author reviews Delta-t's features and connection management in general and outlines some lessons useful for the implementation of high-performance networks. >
---
paper_title: Integrated Layer Processing Can Be Hazardous to Your Performance

paper_content:

Integrated Layer Processing (ILP) has been presented as an implementation technique to improve communication protocol performance by reducing the number of memory references. Previous research has however not pointed out that in some circumstances ILP can significantly increase the number of memory references, resulting in lower communication throughput.
---
paper_title: Protocol implementation using integrated layer processing

paper_content:

Integrated Layer Processing (ILP) is an implementation concept which "permit[s] the implementor the option of performing all the [data] manipulation steps in one or two integrated processing loops" [1]. To estimate the achievable benefits of ILP a file transfer application with an encryption function on top of a user-level TCP has been implemented and the performance of the application in terms of throughput and packet processing times has been measured. The results show that it is possible to obtain performance benefits by integrating marshalling, encryption and TCP checksum calculation. They also show that the benefits are smaller than in simple experiments, where ILP effects have not been evaluated in a complete protocol environment. Simulations of memory access and cache hit rate show that the main benefit of ILP is reduced memory accesses rather than an improved cache hit rate. The results further show that data manipulation characteristics may significantly influence the cache behavior and the achievable performance gain of ILP.
---
paper_title: Impact of Out-of-Sequence Processing on the Performance of Data Transmission

paper_content:

Application Level Framing (ALF) was proposed by Clark and Tennenhouse as an important design principle for developing high performance applications. ALF relies in part on the ability of applications and protocols to process packets independently one from the other. Thus, performance gains one might expect from the use of ALF are clearly related to performance gains one might expect from applications that can handle and process packets received out-of-sequence, as compared to application that require in-sequence delivery (FTP, TELNET, etc.). In this paper, we examine how the ability to process out-of-sequence packets impacts the efficiency of data transmission. We consider both the impact of application parameters such as the time to process a packet by the application, as well as network parameters such as network transmission delay, network loss rate and flow and congestion control characteristics. The performance measure of interest are total latency, buffer requirements, and jitter. We show, using experimental and simulation results, that out-of-sequence processing is beneficial only for very limited ranges of transmission delays and application processing time. We discuss the impact of this on the architecture of communication systems dedicated to distributed multimedia applications.
---
paper_title: Tcp/ip illustrated: the protocols

paper_content:

A reprographic camera has housed in its bellows a remote controlled blind type shutter, so that the photographic material can be masked from day light when the camera is not in use to avoid fog formation in the material. The flexible blind has an exposure aperture suspended between two rollers which are driven by a motor. An AC circuit is connected to said motor during movement of said blind to its open position and a DC circuit is connected to said motor to maintain said blind in its open position.
---
paper_title: Limitations and Implementation Experiences of Integrated Layer Processing

paper_content:

Integrated Layer Processing (ILP) has several limitations on current system environments. Performance evaluations show that the main benefits from ILP are rather a reduced number of memory accesses than an improved cache hit rate. Data manipulation characteristics have significant impact on the cache behavior and on the achievable performance gain of ILP. Future protocol characteristics and efficient implementation concepts for communication systems with CPU expensive data manipulations are proposed.
---
paper_title: Data and Computer Communications

paper_content:

Data and Computer Communications, 9e, is a two-time winner of the best Computer Science and Engineering textbook of the year award from the Textbook and Academic Authors Association. It is ideal for one/two-semester courses in Computer Networks, Data Communications, and Communications Networks in CS, CIS, and Electrical Engineering departments. With a focus on the most current technology and a convenient modular format, this best-selling text offers a clear and comprehensive survey of the entire data and computer communications field. Emphasizing both the fundamental principles as well as the critical role of performance in driving protocol and network design, it explores in detail all the critical technical areas in data communications, wide-area networking, local area networking, and protocol design.
---
paper_title: Architectural considerations for a new generation of protocols

paper_content:

The current generation of protocol architectures, such as TCP/IP or the ISO suite, seem successful at meeting the demands of todays networks. However, a number of new requirements have been proposed for the networks of tomorrow, and some innovation in protocol structuring may be necessary. In this paper, we review some key requirements for tomorrow's networks, and propose some architectural principles to structure a new generation of protocols. In particular, this paper identifies two new design principles, Application Level Framing and Integrated Layer Processing. Additionally, it identifies the presentation layer as a key aspect of overall protocol performance.
---
paper_title: Architectures, features, and implementation of high speed transport protocols

paper_content:

The authors present a comparative study of the characteristics of high speed protocols, new protocol architectures, and implementation techniques for these protocols. They start with a general description of transport protocol services, and follow with a small sample of gigabit applications which might utilize a high speed network. The problems with current transport protocols and protocol architectures are examined. General concepts for high speed protocols and protocol architectures are presented. Specific design techniques suggested for high speed protocols and the potential impact of each are discussed.<<ETX>>
---
paper_title: Architectural considerations for a new generation of protocols

paper_content:

The current generation of protocol architectures, such as TCP/IP or the ISO suite, seem successful at meeting the demands of todays networks. However, a number of new requirements have been proposed for the networks of tomorrow, and some innovation in protocol structuring may be necessary. In this paper, we review some key requirements for tomorrow's networks, and propose some architectural principles to structure a new generation of protocols. In particular, this paper identifies two new design principles, Application Level Framing and Integrated Layer Processing. Additionally, it identifies the presentation layer as a key aspect of overall protocol performance.
---
paper_title: Performance of checksums and CRCs over real data

paper_content:

Checksum and CRC algorithms have historically been studied under the assumption that the data fed to the algorithms was entirely random. This paper examines the behavior of checksums and CRCs over real data from various UNIXr file systems. We show that, when given real data in small to modest pieces (e.g., 48 bytes), all the checksum algorithms have skewed distributions. In one dramatic case, 0.01% of the check values appeared nearly 19% of the time. These results have implications for CRCs and checksums when applied to real data. They also cause a spectacular failure rate for the both TCP and Fletcher's checksums when trying to detect certain types of packet splices.
---
paper_title: Network-conscious image compression

paper_content:

This dissertation proposes network-conscious image compression , a new perspective in image compression that aims not simply to optimize compression, but to optimize overall performance when compressed images are transmitted over a lossy, packet-switched network such as the Internet. Using an Application Level Framing philosophy, an image is compressed into path MTU-size Application Data Units (ADUs) at the application layer. Each ADU carries its semantics, that is, it contains enough information to be processed independently of all other ADUs. Therefore each ADU can be decoded and displayed by the receiving application out-of-order, enabling faster progressive image display. ::: An integral component of this dissertation work has been the design and implementation of Network-Conscious Image Compression and Transmission System (NETCICATS), a software system for empirically investigating the combination of transport protocol features and network-conscious compression algorithms. Developed in the Protocol Engineering Laboratory of University of Delaware, NETCICATS coordinates software components from the network layer (e.g., lossy router), transport layer (e.g., ordered/unordered/partially ordered reliable transport service), and application layer (e.g., compression algorithms, browsers). ::: The network-consciousness hypothesis was first tested by using an earlier version of NETCICATS that allows flexible control of image quality and size, compression algorithms and their parameter settings, and transmission parameters (e.g., QoS parameters, transport service, network loss rate). Initial experiments using wavelet transformed images motivated further investigation of the hypothesis. Two standard image compression algorithms, GIF and SPIHT, were modified to make them network-conscious: GIF-NC and SPIHT-NC. GIF-NC modifies GIF's file structure using an Application Level Framing Approach. SPIHT-NC uses the same wavelet zerotree encoding technique SPIHT uses, but produces an encoded bit stream that can be packetized such that each packet can be processed independently. ::: Experimental results conclude that for certain QoS, network-conscious compressed images can perform better than standard images over lossy packet switched networks. In particular, network-consciousness can provide significant gain at higher loss rates, lower bandwidths, larger round trip delays, and larger window sizes.
---
paper_title: Asymptotically Reliable Transport of Multimedia/Graphics Over Wireless Channels

paper_content:

We propose a multiple-delivery transport service tailored for graphics and video transported over connections with wireless access. This service operates at the interface between the transport and application layers, balancing the subjective delay and image quality objectives of the application with the low reliability and limited bandwidth of the wireless link. While techniques like forward-error correction, interleaving and retransmission improve reliability over wireless links, they also increase latency substantially when bandwidth is limited. Certain forms of interactive multimedia datatypes can benefit from an initial delivery of a corrupt packet to lower the perceptual latency, as long as reliable delivery occurs eventually. Multiple delivery of successively refined versions of the received packet, terminating when a sufficiently reliable version arrives, exploits the redundancy inherently required to improve reliability without a traffic penalty. Modifications to acknowledgment-repeat-request (ARQ) methods to implement this transport service are proposed, which we term `leaky ARQ'. For the specific case of pixel-coded window-based text/graphics, we describe additional functions needed to more effectively support urgent delivery and asymptotic reliability. X server emulation suggests that users will accept a multi-second delay between a (possibly corrupt) packet and the ultimate reliably-delivered version. The relaxed delay for reliable delivery can be exploited for traffic capacity improvement using scheduling of retransmissions.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
---
paper_title: Data and Computer Communications

paper_content:

Data and Computer Communications, 9e, is a two-time winner of the best Computer Science and Engineering textbook of the year award from the Textbook and Academic Authors Association. It is ideal for one/two-semester courses in Computer Networks, Data Communications, and Communications Networks in CS, CIS, and Electrical Engineering departments. With a focus on the most current technology and a convenient modular format, this best-selling text offers a clear and comprehensive survey of the entire data and computer communications field. Emphasizing both the fundamental principles as well as the critical role of performance in driving protocol and network design, it explores in detail all the critical technical areas in data communications, wide-area networking, local area networking, and protocol design.
---
paper_title: Tcp/ip illustrated: the protocols

paper_content:

A reprographic camera has housed in its bellows a remote controlled blind type shutter, so that the photographic material can be masked from day light when the camera is not in use to avoid fog formation in the material. The flexible blind has an exposure aperture suspended between two rollers which are driven by a motor. An AC circuit is connected to said motor during movement of said blind to its open position and a DC circuit is connected to said motor to maintain said blind in its open position.
---
paper_title: Extending TCP for Transactions -- Concepts

paper_content:

This memo discusses extension of TCP to provide transaction-oriented service, without altering its virtual-circuit operation. This extension would fill the large gap between connection-oriented TCP and datagram-based UDP, allowing TCP to efficiently perform many applications for which UDP is currently used. A separate memo contains a detailed functional specification for this proposed extension.
---
paper_title: Evaluation of the effects of protocol processing overhead in error recovery schemes for a high-speed packet switched network: link-by-link versus edge-to-edge schemes

paper_content:

The authors investigate the effects of protocol processing overhead on the performance of error recovery schemes. The focus is on the edge-to-edge error recovery scheme, in which retransmissions of erred packets only take place between source and destination nodes. An approximation is obtained for the Laplace transform for the distribution of the end-to-end packet transfer delay, considering the processing time required for error recovery. The performance of the link-by-link error recovery scheme, in which retransmissions take place between adjacent nodes, is evaluated and compared to the performance of the edge-to-edge scheme. Numerical results from a tandem queuing network model show that for a network with very-high-speed/low-error-rate channels, an edge-to-edge scheme gives a smaller packet transmission delay than a link-by-link scheme for both go-back-N and selective-repeat retransmission procedures, while keeping the packet loss probability sufficiently small. >
---
paper_title: Towards a framework for high-speed communication in a heterogeneous networking environment

paper_content:

A framework is formulated for high-speed communication in an environment comprising a mix of subnetworks with widely varying characteristics. It combines elements of recent work on high-speed packet switching and on interworking of computer networks. The work on high-speed packet switching is expected to lead to the development of large public networks capable of supporting applications ranging from low-speed data to voice, high-speed data and video. Interworking of existing computer networks with high-speed connection-oriented networks will allow them to be used effectively by applications that require the high performance levels such networks can provide. >
---
paper_title: Architectures, features, and implementation of high speed transport protocols

paper_content:

The authors present a comparative study of the characteristics of high speed protocols, new protocol architectures, and implementation techniques for these protocols. They start with a general description of transport protocol services, and follow with a small sample of gigabit applications which might utilize a high speed network. The problems with current transport protocols and protocol architectures are examined. General concepts for high speed protocols and protocol architectures are presented. Specific design techniques suggested for high speed protocols and the potential impact of each are discussed.<<ETX>>
---
paper_title: Why TCP timers don't work well

paper_content:

Repeated observation of TCP retransmission timer problems stimulated investigation into the roles and limitations of timers. Timers are indispensable tools in building up reliable distributed systems. However, as the experience with the TCP retransmission timer has shown, timers have intrinsic limitations in offering optimal performance. Any timeout based action is a guess based on incomplete information, and as such is bound to be non-optimal. We conclude that, if we aim at high performance, we should use external events as a first line of defense against failures, and depend on timers only in cases where external notification has failed.
---
paper_title: Tcp/ip illustrated: the protocols

paper_content:

A reprographic camera has housed in its bellows a remote controlled blind type shutter, so that the photographic material can be masked from day light when the camera is not in use to avoid fog formation in the material. The flexible blind has an exposure aperture suspended between two rollers which are driven by a motor. An AC circuit is connected to said motor during movement of said blind to its open position and a DC circuit is connected to said motor to maintain said blind in its open position.
---
paper_title: Improving round-trip time estimates in reliable transport protocols

paper_content:

As a reliable, end-to-end transport protocol, the ARPA Transmission Control Protocol (TCP) uses positive acknowledgements and retransmission to guarantee delivery. TCP implementations are expected to measure and adapt to changing network propagation delays so that its retransmission behavior balances user throughput and network efficiency. However, TCP suffers from a problem we call retransmission ambiguity: when an acknowledgment arrives for a segment that has been retransmitted, there is no indication which transmission is being acknowledged. Many existing TCP implementations do not handle this problem correctly. This paper reviews the various approaches to retransmission and presents a novel and effective approach to the retransmission ambiguity problem.
---
paper_title: Block acknowledgement: redesigning the window protocol

paper_content:

We describe a new version of the window protocol where message sequence numbers are taken from a finite domain and where both message disorder and loss can be tolerated. Most existing window protocols achieve only one of these two goals. Our protocol is based on a new method of acknowledgement, called <italic>block acknowledgement</italic>, where each acknowledgement message has two numbers <italic>m</italic> and <italic>n</italic> to acknowledge the reception of all data messages with sequence numbers ranging from <italic>m</italic> to <italic>n</italic>. Using this method of acknowledgement, the proposed protocol achieves the two goals while maintaining the same data transmission capability of the traditional window protocol.
---
paper_title: Efficient at-most-once messages based on synchronized clocks

paper_content:

This paper describes a new message passing protocol that provides guaranteed detection of duplicate messages even when the receiver has no state stored for the sender. It also discusses how to use these messages to implement higher-level primitives such as at-most-once remote procedure calls and sequenced bytestream protocols, and describes an implementation of at-most-once RPCs using our method. Our performance measurements indicate that at-most-once RPCs can be provided at the same cost as less desirable RPCs that do not guarantee at-most-once execution. Our method is based on the assumption that clocks throughout the system are loosely synchronized. Modern clock synchronization protocols provide good bounds on clock skew with high probability; our method depends on the bound for performance but not for correctness.
---
paper_title: Design and implementation of a high-speed transport protocol

paper_content:

The design, analysis, and implementation of an end-to-end transport protocol that is capable of high throughput consistent with the evolving high-speed physical networks based on fiber-optic transmission lines and high-capacity switches are presented. Unlike current transport protocols in which changes in control/state information are exchanged between the two communicating entities only when some significant event occurs, this protocol exchanges relevant and full state information periodically and frequently. It is shown that this reduces the complexity of protocol processing by removing many of the procedures required to recover from network inadequacies such as bit errors, packet loss, and out-of-sequence packets and makes it more amenable to parallel processing. Also, to increase channel utilization in the presence of high-speed, long-latency networks and to support diagrams, and efficient implementation of the selective repeat method of error control is incorporated in the protocol. An implementation using a Motorola 68030-based multiprocessor as a front-end processor is described. The current implementation can comfortably handle 10-15 kpackets/s. >
---
paper_title: Data and Computer Communications

paper_content:

Data and Computer Communications, 9e, is a two-time winner of the best Computer Science and Engineering textbook of the year award from the Textbook and Academic Authors Association. It is ideal for one/two-semester courses in Computer Networks, Data Communications, and Communications Networks in CS, CIS, and Electrical Engineering departments. With a focus on the most current technology and a convenient modular format, this best-selling text offers a clear and comprehensive survey of the entire data and computer communications field. Emphasizing both the fundamental principles as well as the critical role of performance in driving protocol and network design, it explores in detail all the critical technical areas in data communications, wide-area networking, local area networking, and protocol design.
---
paper_title: Error and flow control performance of a high speed protocol

paper_content:

The performance of the SNR protocol of A. N. Netravali et al. (1990) is studied when it is implemented for end-to-end flow and error control. Using a combination of analysis and simulation, the efficiency with which this protocol uses the network bandwidth and its achievable throughput is evaluated as a function of certain network and protocol parameters. The protocol is enhanced by introducing two windows to decouple the two functions of receiver flow control and network congestion control. This enhancement and the original protocol are compared with go-back-N (GBN) and one-at-a-time-selective-repeat (OSR) retransmission procedures, are shown to have significantly higher throughput for a wide range of network conditions. As an example, for a virtual circuit with 60-ms roundtrip delay and 10/sup -8/ bit error rate, in order to deliver 500 Mb/s throughput, both the GBN and OSR require a raw transmission bandwidth of approximately 800 Mb/s, whereas SNR with two windows needs slightly higher than 500 Mb/s raw bandwidth. Periodic exchange of state can also provide a variety of measures for congestion control in a timely and accurate fashion. >
---
paper_title: Architectures, features, and implementation of high speed transport protocols

paper_content:

The authors present a comparative study of the characteristics of high speed protocols, new protocol architectures, and implementation techniques for these protocols. They start with a general description of transport protocol services, and follow with a small sample of gigabit applications which might utilize a high speed network. The problems with current transport protocols and protocol architectures are examined. General concepts for high speed protocols and protocol architectures are presented. Specific design techniques suggested for high speed protocols and the potential impact of each are discussed.<<ETX>>
---
paper_title: Transport layer for cooperative multimedia applications

paper_content:

This paper presents work carried out within the Cesame project for the design of a multimedia highspeed distributed transport provider. The term transport provider is used to target a reference framework but does not preclude any standardized reference model. It gives the objectives and relates the main contributions obtained during the first year of the project. The goal of this task is to monitor, select and design services, protocols and mechanisms for defining a transport provider to support distributed multimedia services. As far as architectural aspects are concerned, a refinement of reference models is mandatory, and work on this topic has already been started within several institutions. Moreover, it is worth to mention that the transport provider will have first to run on top ofAtm/Aal networks and is expected on top of other networks.
---
paper_title: Communication Networks: A First Course

paper_content:

From the Publisher: ::: The second edition of this very successful text provides thorough coverage of networks, including applications, protocols, compression, security and transmission links. Both students and current practitioners will benefit from Walrand's clear presentation of networking concepts.
---
paper_title: A framework of architectural concepts for high-speed communication systems

paper_content:

A framework for understanding high-speed communication architectures and protocols is presented. The framework is validated by showing how several concepts fit into it. Two approaches to reduce the number of processing operations required for a single datum, the reduction of control processing and the elimination of unneeded or replicated operations, are discussed. Two other approaches for increasing communication system speed by performing more processing operations per unit time, parallel processing and increased processor utilization, are also discussed. >
---
paper_title: A taxonomy for congestion control algorithms in packet switching networks

paper_content:

The authors propose a new taxonomy for congestion control algorithms in packet switching computer networks based on control theory. They view a network as a large, distributed control system, in which a congestion control scheme is a (distributed) control policy executable at each node (host or switches) of the network in order to a certain level of stable conditions. This taxonomy provides a coherent framework for the comparative study of existing algorithms and offers clues toward the development of new congestion control strategies. >
---
paper_title: Data and Computer Communications

paper_content:

Data and Computer Communications, 9e, is a two-time winner of the best Computer Science and Engineering textbook of the year award from the Textbook and Academic Authors Association. It is ideal for one/two-semester courses in Computer Networks, Data Communications, and Communications Networks in CS, CIS, and Electrical Engineering departments. With a focus on the most current technology and a convenient modular format, this best-selling text offers a clear and comprehensive survey of the entire data and computer communications field. Emphasizing both the fundamental principles as well as the critical role of performance in driving protocol and network design, it explores in detail all the critical technical areas in data communications, wide-area networking, local area networking, and protocol design.
---
paper_title: Communication Networks: A First Course

paper_content:

From the Publisher: ::: The second edition of this very successful text provides thorough coverage of networks, including applications, protocols, compression, security and transmission links. Both students and current practitioners will benefit from Walrand's clear presentation of networking concepts.
---
paper_title: Specification and analysis of the SNR high-speed transport protocol

paper_content:

The emergence of optical fiber and its correspondingly high data rates have led to the development of much higher speed networks, both locally and over the long haul. These developments led to the design of new transport protocols, which were intended to take advantage of the high-speed networks. A number of these so-called "high-speed transport protocols" have been designed to date. This paper considers one of these, called the SNR protocol, in detail. A formal specification of the protocol is presented, using the protocol model systems of communicating machines, and the protocol is then analyzed through the specification. An implementation of the protocol based on this formal definition has also been made, and used to simulate the protocol, providing further insights into its performance. Based on the combined results of the analysis and the simulated protocol, a high degree of confidence is gained in the correctness of the protocol. The specification is quite detailed, and from it an implementation should be fairly straightforward. The paper also discusses the difficulties encountered during the analysis of such a complex protocol, and suggests some possible solutions to these problems. Finally, as a result of this work, we comment on the strengths and weakness of the SNR protocol as a solution to the high-speed transport protocol problem, and make two simple suggestions for improving it. >
---
paper_title: Data and Computer Communications

paper_content:

Data and Computer Communications, 9e, is a two-time winner of the best Computer Science and Engineering textbook of the year award from the Textbook and Academic Authors Association. It is ideal for one/two-semester courses in Computer Networks, Data Communications, and Communications Networks in CS, CIS, and Electrical Engineering departments. With a focus on the most current technology and a convenient modular format, this best-selling text offers a clear and comprehensive survey of the entire data and computer communications field. Emphasizing both the fundamental principles as well as the critical role of performance in driving protocol and network design, it explores in detail all the critical technical areas in data communications, wide-area networking, local area networking, and protocol design.
---
paper_title: Packet-Pair Flow Control

paper_content:

This paper presents the packet-pair rate-based feedback flow control scheme. This scheme is designed for networks where individual connections do not reserve bandwidth and for the available bitrate (best-effort) component of integrated networks. We assume a round-robin-like queue service discipline in the output queues of the network’s switches, and propose a linear stochastic model for a single conversation in a network of such switches. These model motivates the Packet-Pair rate probing technique, which forms the basis for provably stable discrete and continuous time rate-based flow control schemes. We present a novel state estimation scheme based on fuzzy logic. We then address several practical concerns: dealing with system startup, retransmission and timeout strategy, and dynamic setpoint probing. We present a finite state machine as well as source code for a model implementation. The dynamics of a single source, the interactions of multiple sources, and the behavior of packet-pair sources in a variety of benchmark scenarios are evaluated by means of detailed simulations. We close with some remarks about possible extensions to packet-pair, limitations of this work, and an outline of related work.
---
paper_title: Evaluation of TCP Vegas: emulation and experiment

paper_content:

This paper explores the claims that TCP Vegas [2] both uses network bandwidth more efficiently and achieves higher network throughput than TCP Reno [6]. It explores how link bandwidth, network buffer capacity, TCP receiver acknowledgment algorithm, and degree of network congestion affect the relative performance of Vegas and Reno.
---
paper_title: A binary feedback scheme for congestion avoidance in computer networks with a connectionless network layer

paper_content:

Polymers in which the side branches contain optically active 2-(4-methyl-cyclohex-3-en-1-yl)-propyl groups, and their preparation. The new polymers are used for the production of moldings, coatings and adhesives, and for finishing paper or textiles. They have K values of from 20 to 140.
---
paper_title: Random early detection gateways for congestion avoidance

paper_content:

The authors present random early detection (RED) gateways for congestion avoidance in packet-switched networks. The gateway detects incipient congestion by computing the average queue size. The gateway could notify connections of congestion either by dropping packets arriving at the gateway or by setting a bit in packet headers. When the average queue size exceeds a present threshold, the gateway drops or marks each arriving packet with a certain probability, where the exact probability is a function of the average queue size. RED gateways keep the average queue size low while allowing occasional bursts of packets in the queue. During congestion, the probability that the gateway notifies a particular connection to reduce its window is roughly proportional to that connection's share of the bandwidth through the gateway. RED gateways are designed to accompany a transport-layer congestion control protocol such as TCP. The RED gateway has no bias against bursty traffic and avoids the global synchronization of many connections decreasing their window at the same time. Simulations of a TCP/IP network are used to illustrate the performance of RED gateways. >
---
paper_title: Communication Networks: A First Course

paper_content:

From the Publisher: ::: The second edition of this very successful text provides thorough coverage of networks, including applications, protocols, compression, security and transmission links. Both students and current practitioners will benefit from Walrand's clear presentation of networking concepts.
---
paper_title: Transport layer for cooperative multimedia applications

paper_content:

This paper presents work carried out within the Cesame project for the design of a multimedia highspeed distributed transport provider. The term transport provider is used to target a reference framework but does not preclude any standardized reference model. It gives the objectives and relates the main contributions obtained during the first year of the project. The goal of this task is to monitor, select and design services, protocols and mechanisms for defining a transport provider to support distributed multimedia services. As far as architectural aspects are concerned, a refinement of reference models is mandatory, and work on this topic has already been started within several institutions. Moreover, it is worth to mention that the transport provider will have first to run on top ofAtm/Aal networks and is expected on top of other networks.
---
paper_title: Tcp/ip illustrated: the protocols

paper_content:

A reprographic camera has housed in its bellows a remote controlled blind type shutter, so that the photographic material can be masked from day light when the camera is not in use to avoid fog formation in the material. The flexible blind has an exposure aperture suspended between two rollers which are driven by a motor. An AC circuit is connected to said motor during movement of said blind to its open position and a DC circuit is connected to said motor to maintain said blind in its open position.
---
paper_title: NETBLT: A bulk data transfer protocol

paper_content:

This document is a description of, and a specification for, the NETBLT ::: protocol. It is a revision of the specification published in RFC-969. ::: NETBLT (NETwork BLock Transfer) is a transport level protocol intended ::: for the rapid transfer of a large quantity of data between computers. ::: It provides a transfer that is reliable and flow controlled, and is ::: designed to provide maximum throughput over a wide variety of ::: networks. Although NETBLT currently runs on top of the Internet ::: Protocol (IP), it should be able to operate on top of any datagram ::: protocol similar in function to IP. This document is published for ::: discussion and comment, and does not constitute a standard. The ::: proposal may change and certain parts of the protocol have not yet ::: been specified; implementation of this document is therefore not ::: advised. Obsoletes RFC-969.
---
paper_title: Protocols for high-speed multimedia communications networks

paper_content:

Abstract This paper surveys protocols and networks for multimedia applications. The first section defines the most important needs of multimedia aplications, and expresses their requirements as Quality of Service (QoS) parameters. A second part describes current high-speed networks and the services they offer. Protocols providing stream services in packet switching networks are introduced in the third part. Finally, several existing transport protocols are presented and their main features are analysed.
---
paper_title: Extending TCP for Transactions -- Concepts

paper_content:

This memo discusses extension of TCP to provide transaction-oriented service, without altering its virtual-circuit operation. This extension would fill the large gap between connection-oriented TCP and datagram-based UDP, allowing TCP to efficiently perform many applications for which UDP is currently used. A separate memo contains a detailed functional specification for this proposed extension.
---
paper_title: TIME-WAIT Assassination Hazards in TCP

paper_content:

This note describes some theoretically-possible failure modes for TCP connections and discusses possible remedies. In particular, one very simple fix is identified.
---
paper_title: DecNet Phase V: An OSI Implementation

paper_content:

From the Publisher: ::: A Practical Perspective On OSI Broaden your understanding of how large networks are designed with this introduction to the concepts surrounding Digital Network Architecture. This useful book blends an OSI tutorial with a complete look at how OSI technology is used in a Digital computer network. You'll gain useful insights into OSI and the process of OSI standardization and implementation - all presented in a straightforward, easy-to-follow style.
---
paper_title: Specification and analysis of the SNR high-speed transport protocol

paper_content:

The emergence of optical fiber and its correspondingly high data rates have led to the development of much higher speed networks, both locally and over the long haul. These developments led to the design of new transport protocols, which were intended to take advantage of the high-speed networks. A number of these so-called "high-speed transport protocols" have been designed to date. This paper considers one of these, called the SNR protocol, in detail. A formal specification of the protocol is presented, using the protocol model systems of communicating machines, and the protocol is then analyzed through the specification. An implementation of the protocol based on this formal definition has also been made, and used to simulate the protocol, providing further insights into its performance. Based on the combined results of the analysis and the simulated protocol, a high degree of confidence is gained in the correctness of the protocol. The specification is quite detailed, and from it an implementation should be fairly straightforward. The paper also discusses the difficulties encountered during the analysis of such a complex protocol, and suggests some possible solutions to these problems. Finally, as a result of this work, we comment on the strengths and weakness of the SNR protocol as a solution to the high-speed transport protocol problem, and make two simple suggestions for improving it. >
---
paper_title: Data and Computer Communications

paper_content:

Data and Computer Communications, 9e, is a two-time winner of the best Computer Science and Engineering textbook of the year award from the Textbook and Academic Authors Association. It is ideal for one/two-semester courses in Computer Networks, Data Communications, and Communications Networks in CS, CIS, and Electrical Engineering departments. With a focus on the most current technology and a convenient modular format, this best-selling text offers a clear and comprehensive survey of the entire data and computer communications field. Emphasizing both the fundamental principles as well as the critical role of performance in driving protocol and network design, it explores in detail all the critical technical areas in data communications, wide-area networking, local area networking, and protocol design.
---
paper_title: Specification and analysis of the SNR high-speed transport protocol

paper_content:

The emergence of optical fiber and its correspondingly high data rates have led to the development of much higher speed networks, both locally and over the long haul. These developments led to the design of new transport protocols, which were intended to take advantage of the high-speed networks. A number of these so-called "high-speed transport protocols" have been designed to date. This paper considers one of these, called the SNR protocol, in detail. A formal specification of the protocol is presented, using the protocol model systems of communicating machines, and the protocol is then analyzed through the specification. An implementation of the protocol based on this formal definition has also been made, and used to simulate the protocol, providing further insights into its performance. Based on the combined results of the analysis and the simulated protocol, a high degree of confidence is gained in the correctness of the protocol. The specification is quite detailed, and from it an implementation should be fairly straightforward. The paper also discusses the difficulties encountered during the analysis of such a complex protocol, and suggests some possible solutions to these problems. Finally, as a result of this work, we comment on the strengths and weakness of the SNR protocol as a solution to the high-speed transport protocol problem, and make two simple suggestions for improving it. >
---
paper_title: The Delta-t transport protocol: features and experience

paper_content:

With the advent of new high performance networks and distribution systems there is renewed interest in transport protocol designs that can support both request/response and stream styles of communication. The author examines Delta-t, a transport protocol designed to meet such goals. Delta-t's main contribution is in the area of connection management, where it achieves hazard-free connection management without explicit packet exchanges. The author reviews Delta-t's features and connection management in general and outlines some lessons useful for the implementation of high-performance networks. >
---
paper_title: An Analytic Study of Partially Ordered Transport Services

paper_content:

This paper presents an analytic model for investigating the throughput, delay and buffer utilization characteristics of partially ordered transport services. We analyze the effects of packet and ack losses as well as applications' order requirements on overall system performance. The analytic model is verified by comparing its results against those of an OPNET simulation model. Analytic results show that for applications that can tolerate some reordering in the delivery of objects, use of partially ordered service instead of ordered service provides important buffer utilization and delay improvements, particularly as the loss rate increases and the order requirements of applications decrease. In terms of throughput, it makes no difference which service (i.e., ordered, partially ordered, unordered) an application uses. Analytic study also shows that by judicious choice of sender's transmission order, overall system performance can further be improved in a partially ordered service.
---
paper_title: The MultiStream protocol: a highly flexible high-speed transport protocol

paper_content:

A transport layer protocol designed to meet the wide-ranging needs of high-speed applications is described. A unique feature of this protocol is that its behavior, defined by a set of functions, may be modified dynamically over the life of a connection without loss of reliable data transfer. This property makes the protocol attractive for supporting applications, such as multimedia applications that require different protocol support for different portions of their traffic streams. The protocol has been verified to reliably deliver data and manage connections and to contain no deadlocks or loops. A parallel architecture for implementing the protocol has also been verified. Analysis of a skeleton implementation shows that the protocol has the potential to receive data at a rate of over 150 kpackets/s if 10-MIPS processors are used in the implementation. >
---
paper_title: IP over ATM: A Framework Document

paper_content:

The discussions of the IP over ATM working group over the last several years have produced a diverse set of proposals, some of which are no longer under active consideration. A categorization is provided for the purpose of focusing discussion on the various proposals for IP over ATM deemed of primary interest by the IP over ATM working group. The intent of this framework is to help clarify the differences between proposals and identify common features in order to promote convergence to a smaller and more mutually compatible set of standards. In summary, it is hoped that this document, in classifying ATM approaches and issues will help to focus the IP over ATM working group's direction.
---
paper_title: Error and flow control performance of a high speed protocol

paper_content:

The performance of the SNR protocol of A. N. Netravali et al. (1990) is studied when it is implemented for end-to-end flow and error control. Using a combination of analysis and simulation, the efficiency with which this protocol uses the network bandwidth and its achievable throughput is evaluated as a function of certain network and protocol parameters. The protocol is enhanced by introducing two windows to decouple the two functions of receiver flow control and network congestion control. This enhancement and the original protocol are compared with go-back-N (GBN) and one-at-a-time-selective-repeat (OSR) retransmission procedures, are shown to have significantly higher throughput for a wide range of network conditions. As an example, for a virtual circuit with 60-ms roundtrip delay and 10/sup -8/ bit error rate, in order to deliver 500 Mb/s throughput, both the GBN and OSR require a raw transmission bandwidth of approximately 800 Mb/s, whereas SNR with two windows needs slightly higher than 500 Mb/s raw bandwidth. Periodic exchange of state can also provide a variety of measures for congestion control in a timely and accurate fashion. >
---
paper_title: Performance analysis of partially ordered and partially reliable transport services

paper_content:

The performance of a new class of transport layer services, called partially ordered/partially reliable, is investigated through analytic modeling and simulation. These services fill the gap between traditional ordered/reliable (e.g., TCP) and unordered/unreliable (e.g., UDP) transport services by allowing an application to specify controlled levels of loss and reordering. We show the performance improvements by using partially ordered/partially reliable services as compared to ordered/reliable service. We also analyze the effects various network and application parameters on the system performance. ::: Results show that the use of ordered/reliable transport service when an application only needs a partially ordered/partially reliable service can cause considerable throughput drops, delay increases and buffer utilization increases in lossy networks. On the other hand, at high loss rates, unordered/unreliable service is unable to respect an application's loss and reordering tolerances. Thus, in lossy environments, partially ordered/partially reliable service is necessary to avoid the extra cost of ordered/reliable transport service, and, at the same time, to guarantee the minimal reordering and reliability that an application requires.
---
paper_title: Performance Interactions between P-HTTP and TCP Implementations

paper_content:

This document describes several performance problems resulting from interactions between implementations of persistent-HTTP (P-HTTP) and TCP. Two of these problems tie P-HTTP performance to TCP delayed-acknowledgments, thus adding up to 200ms to each P-HTTP transaction. A third results in multiple slow-starts per TCP connection. Unresolved, these problems result in P-HTTP transactions which are 14 times slower than standard HTTP and 20 times slower than potential P-HTTP over a 10 Mb/s Ethernet. We describe each problem and potential solutions. After implementing our solutions to two of the problems, we observe that P-HTTP performs better than HTTP on a local Ethernet. Although we observed these problems in specific implementations of HTTP and TCP (Apache-1.1b4 and SunOS 4.1.3, respectively), we believe that these problems occur more widely.
---
paper_title: Improving End-to-End Performance of TCP over Mobile Internetworks

paper_content:

Reliable transport protocols such as TCP use end-to-end flow, congestion and error control mechanisms to provide reliable delivery over an internetwork. However, the end-to-end performance of a TCP connection can suffer significant degradation in the presence of a wireless link. We are exploring alternatives for optimizing end-to-end performance of TCP connections across an internetwork consisting of both fixed and mobile networks. The central idea in our approach is to transparently split an end-to-end connection into two separate connections; one over the wireless link and other over the wired path. The connection over the wireless link may either use regular TCP or a specialized transport protocol optimized for better performance over a wireless link. Our approach does not require any changes to the existing protocol software on stationary hosts. Results of a systematic performance evaluation using both our approach and regular TCP show that our approach yields significant performance improvements.
---
paper_title: Improving reliable transport and handoff performance in cellular wireless networks

paper_content:

TCP is a reliable transport protocol tuned to perform well in traditional networks where congestion is the primary cause of packet loss. However, networks with wireless links and mobile hosts incur significant losses due to bit-errors and hand-offs. This environment violates many of the assumptions made by TCP, causing degraded end-to-end performance. In this paper, we describe the additions and modifications to the standard Internet protocol stack (TCP/IP) to improve end-to-end reliable transport performance in mobile environments. The protocol changes are made to network-layer software at the base station and mobile host, and preserve the end-to-end semantics of TCP. One part of the modifications, called the snoop module, caches packets at the base station and performs local retransmissions across the wireless link to alleviate the problems caused by high bit-error rates. The second part is a routing protocol that enables low-latency handoff to occur with negligible data loss. We have implemented this new protocol stack on a wireless testbed. Our experiments show that this system is significantly more robust at dealing with unreliable wireless links than normal TCP; we have achieved throughput speedups of up to 20 times over regular TCP and handoff latencies over 10 times shorter than other mobile routing protocols.
---
paper_title: Asymptotically Reliable Transport of Multimedia/Graphics Over Wireless Channels

paper_content:

We propose a multiple-delivery transport service tailored for graphics and video transported over connections with wireless access. This service operates at the interface between the transport and application layers, balancing the subjective delay and image quality objectives of the application with the low reliability and limited bandwidth of the wireless link. While techniques like forward-error correction, interleaving and retransmission improve reliability over wireless links, they also increase latency substantially when bandwidth is limited. Certain forms of interactive multimedia datatypes can benefit from an initial delivery of a corrupt packet to lower the perceptual latency, as long as reliable delivery occurs eventually. Multiple delivery of successively refined versions of the received packet, terminating when a sufficiently reliable version arrives, exploits the redundancy inherently required to improve reliability without a traffic penalty. Modifications to acknowledgment-repeat-request (ARQ) methods to implement this transport service are proposed, which we term `leaky ARQ'. For the specific case of pixel-coded window-based text/graphics, we describe additional functions needed to more effectively support urgent delivery and asymptotic reliability. X server emulation suggests that users will accept a multi-second delay between a (possibly corrupt) packet and the ultimate reliably-delivered version. The relaxed delay for reliable delivery can be exploited for traffic capacity improvement using scheduling of retransmissions.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
---
paper_title: Architectures, features, and implementation of high speed transport protocols

paper_content:

The authors present a comparative study of the characteristics of high speed protocols, new protocol architectures, and implementation techniques for these protocols. They start with a general description of transport protocol services, and follow with a small sample of gigabit applications which might utilize a high speed network. The problems with current transport protocols and protocol architectures are examined. General concepts for high speed protocols and protocol architectures are presented. Specific design techniques suggested for high speed protocols and the potential impact of each are discussed.<<ETX>>
---
paper_title: AIRMAIL: A Link-Layer Protocol for Wireless Networks

paper_content:

This paper describes the design and performance of a link-layer protocol for indoor and outdoor wireless networks. The protocol is asymmetric to reduce the processing load at the mobile, reliability is established by a combination of automatic repeat request and forward error correction, and link-layer packets are transferred appropriately during handoffs. The protocol is named AIRMAIL (AsymmetrIc Reliable Mobile Access In Link-layer). The asymmetry is needed in the design because the mobile terminals have limited power and smaller processing capability than the base stations. The key ideas in the asymmetric protocol design consist of placing bulk of the intelligence in the base station as opposed to placing it symmetrically, in requiring the mobile terminal to combine several acknowledgments into a single acknowledgment to conserve power, and in designing the base stations to send periodic status messages, while making the acknowledgment from the mobile terminal event-driven. The asymmetry in the protocol design results in a one-third reduction of compiled code. The forward error correction technique incorporates three levels of channel coding which interact adaptively. The motivation for using a combination of forward error correction and link-layer retransmissions is to obtain better performance in terms of end-to-end throughput and latency by correcting errors in an unreliable wireless channel in addition to end-to-end correction rather than by correcting errors only by end-to-end retransmissions. The coding overhead is changed adaptively so that bandwidth expansion due to forward error correction is minimized. Integrity of the link during handoffs (in the face of mobility) is handled by window management and state transfer. The protocol has been implemented. Experimental performance results based on the implementation are presented.
---
paper_title: Implementation and performance evaluation of Indirect TCP

paper_content:

With the advent of small portable computers and the technological advances in wireless communications, mobile wireless computing is likely to become very popular in the near future. Wireless links are slower and less reliable compared to wired links and are prone to loss of signal due to noise and fading. Furthermore, host mobility can give rise to periods of disconnection from the fixed network. The use of existing network protocols, which were developed mainly for the high bandwidth and faster wired links, with mobile computers thus gives rise to unique performance problems arising from host mobility and due to the characteristics of wireless medium. Indirect protocols can isolate mobility and wireless related problems using mobility support routers (MSRs) as intermediaries, which also provide backward compatibility with fixed network protocols. We present the implementation and performance evaluation of I-TCP, which is an indirect transport layer protocol for mobile wireless environments. Throughput comparison with regular (BSD) TCP shows that I-TCP performs significantly better in a wide range of conditions related to wireless losses and host mobility. We also describe the implementation and performance of I-TCP handoffs.
---
paper_title: Architectures, features, and implementation of high speed transport protocols

paper_content:

The authors present a comparative study of the characteristics of high speed protocols, new protocol architectures, and implementation techniques for these protocols. They start with a general description of transport protocol services, and follow with a small sample of gigabit applications which might utilize a high speed network. The problems with current transport protocols and protocol architectures are examined. General concepts for high speed protocols and protocol architectures are presented. Specific design techniques suggested for high speed protocols and the potential impact of each are discussed.<<ETX>>
---

Title: The Transport Layer: Tutorial and Survey

Section 1: INTRODUCTION
Description 1: Discusses the role of the transport layer in the OSI 7-layer Reference Model, focusing on the importance of TCP as a reference point and provides an overview of the paper's structure.

Section 2: TRANSPORT LAYER CONCEPTS AND TERMINOLOGY
Description 2: Introduces transport layer concepts and terminology through an example involving TCP and illustrates the general role and basic operation of the transport layer.

Section 3: TRANSPORT SERVICE
Description 3: Classifies the typical services provided by the transport layer, focusing on the abstraction of functions for the higher layer and distinguishing the differences between service and protocol.

Section 4: TRANSPORT PROTOCOL FEATURES
Description 4: Describes the internal mechanisms of transport layer protocols that provide the discussed services, highlighting features such as connection-oriented versus connectionless protocols, error control, flow control, and more.

Section 5: TRANSPORT PROTOCOL EXAMPLES
Description 5: Summarizes widely implemented or influential transport protocols other than TCP, detailing their features in terms of the service and protocol features discussed.

Section 6: FUTURE DIRECTIONS AND CONCLUSION
Description 6: Summarizes the impact of recent trends and technological developments on transport protocol design, with emphasis on wireless networking, debates in transport protocol research, and final observations about the implications and future of transport protocols.

Section 7: APPENDIX
Description 7: Provides summary tables comparing TCP and various transport protocols discussed in the paper, organizing features and services for easy reference.