Agent based Congestion Control Performance in Mobile ad-hoc Network:A Survey paper
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paper_title: Congestion-Aware Routing Protocol for Mobile Ad Hoc Networks

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Congestion in mobile ad hoc networks leads to transmission delays and packet loss, and causes wastage of time and energy on recovery. Routing protocols which are adaptive to the congestion status of a mobile ad hoc network can greatly improve the network performance. In this paper, we propose a congestion-aware routing protocol for mobile ad hoc networks which uses a metric incorporating data-rate, MAC overhead, and buffer delay to combat congestion. This metric is used, together with the avoidance of mismatched link data-rate routes, to make mobile ad hoc networks robust and adaptive to congestion.
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paper_title: A Survey on Congestion Control for Mobile Ad-Hoc Networks

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Congestion control is a key problem in mobile ad hoc networks. The standard congestion control mechanism of the Transmission Control Protocol (TCP) is not able to handle the special properties of a shared wireless multi-hop channel well. In particular, the frequent changes of the network topology and the shared nature of the wireless channel pose significant challenges. Many approaches have been proposed to overcome these difficulties. In this paper, we give an overview over existing proposals, explain their key ideas and show their interrelations. Copyright © 2007 John Wiley & Sons, Ltd.
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paper_title: A Hop-by-Hop Congestion-Aware Routing Protocol for Heterogeneous Mobile Ad-hoc Networks

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In Heterogeneous mobile ad hoc networks (MANETs) congestion occurs with limited resources. Due to the shared wireless channel and dynamic topology, packet transmissions suffer from interference and fading. In heterogeneous ad hoc networks, throughput via a given route is depending on the minimum data rate of all its links. In a route of links with various data rates, if a high data rate node forwards more traffic to a low data rate node, there is a chance of congestion, which leads to long queuing delays in such routes. Since hop count is used as a routing metric in traditional routing, it do not adapt well to mobile nodes. A congestion-aware routing metric for MANETs should incorporate transmission capability, reliability, and congestion around a link. In this paper, we propose to develop a hop-by-hop congestion aware routing protocol which employs a combined weight value as a routing metric, based on the data rate, queuing delay, link quality and MAC overhead. Among the discovered routes, the route with minimum cost index is selected, which is based on the node weight of all the in-network nodes. Simulation results prove that our proposed routing protocol attains high throughput and packet delivery ratio, by reducing the packet drop and delay.
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paper_title: Rate-based transport control for mobile ad hoc networks

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The traditional congestion control mechanism, i.e., TCP, when applied in mobile ad hoc networks (MANET), encounters a number of new challenges, such as wireless link error, medium contention and frequent route failures. Very poor performance of TCP in MANET has been reported in many recent studies. We focus on the problems resulting from medium contention and propose a novel rate based end-to-end congestion control scheme (RBCC). We first illustrate that, under the impact of medium contention, a window based congestion control algorithm is unstable and hence may not be appropriate for MANET because the optimum congestion window size is very small and may even be less than one, i.e., the source should send less than one packet in one round trip time (RTT). Based on the novel use of channel busyness ratio, which, we show, is an accurate sign of the network utilization and congestion status, a new rate control scheme has been proposed to support the transport service in MANET efficiently and reliably. In RBCC, a sublayer consisting of a leaky bucket is added under TCP to control the sending rate based on the network layer feedback at the bottleneck node. Extensive simulations show that our scheme significantly outperforms traditional TCP in terms of channel utilization, delay and fairness.
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paper_title: A Performance Comparison of Equation-Based and GAIMD Congestion Control in Mobile Ad Hoc Networks

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Fast-growing applications like streaming media make TCP a poor fit. Because the UDP protocol lacks congestion control, equation-based and AIMD-based congestion control schemes have been two promising alternative to TCP for real-time multimedia streaming over the Internet. Past studies have shown that they are able to maintain throughput smoothness and achieve reasonable fairness with competing TCP flows in wireline networks. However, their behavior remains not clear in mobile ad hoc network (MANET). In this paper, we compare the general AIMD-based congestion control mechanism (GAIMD) with equation-based congestion control mechanism (TFRC TCP-friendly rate control) over a wide range of MANET scenario, in terms of throughput fairness and smoothness. Our results show that TFRC and GAIMD (0.2, 0.125) are able to maintain throughput smoothness in MANET, but at the same time, they obtain less throughput than the competing TCP flows. Our results also show that TFRC changes its sending rate more smoothly than GAIMD (0.2, 0.125) does, but it gets the least throughput compares with TCP and GAIMD (0.2, 0.125).
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paper_title: Hop-by-hop congestion control over a wireless multi-hop network

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This paper focuses on congestion control over multi-hop, wireless networks. In a wireless network, an important constraint that arises is that due to the MAC (media access control) layer. Many wireless MACs use a time-division strategy for channel access, where, at any point in space, the physical channel can be accessed by a single user at each instant of time. We develop a fair hop-by-hop congestion control algorithm with the MAC constraint being imposed in the form of a channel access time constraint, using an optimization based framework. In the absence of delay, we show that this algorithm is globally stable using a Lyapunov function based approach. Next, in the presence of delay, we show that the hop-by-hop control algorithm has the property of spatial spreading. In other words, focused loads at a particular spatial location in the network get "smoothed" over space. We derive bounds on the "peak load" at a node, both with hop-by-hop control, as well as with end-to-end control, show that significant gains are achieved with the hop-by-hop scheme, and validate the analytical results with simulation.
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paper_title: Joint Scheduling and Congestion Control in Mobile Ad-Hoc Networks

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In this paper we study the problem of jointly performing scheduling and congestion control in mobile ad-hoc networks so that network queues remain bounded and the resulting flow rates satisfy an associated network utility maximization problem. In recent years a number of papers have presented theoretical solutions to this problem that are based on combining differential-backlog scheduling algorithms with utility-based congestion control. However, this work typically does not address a number of issues such as how signaling should be performed and how the new algorithms interact with other wireless protocols. In this paper we address such issues. In particular: ldr We define a specific network utility maximization problem that we believe is appropriate for mobile adhoc networks. ldr We describe a wireless greedy primal dual (wGPD) algorithm for combined congestion control and scheduling that aims to solve this problem. ldr We show how the wGPD algorithm and its associated signaling can be implemented in practice with minimal disruption to existing wireless protocols. ldr We show via OPNET simulation that wGPD significantly outperforms standard protocols such as 802.11 operating in conjunction with TCP. This work was supported by the DARPA CBMANET program.
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paper_title: A CLUSTER BASED CONGESTION CONTROL PROTOCOL FOR MOBILE ADHOC NETWORKS

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In mobile ad hoc networks (MANETs) congestion occurs with limited resources. Congestion leads to packet losses and bandwidth degradation and also wastes time and energy on congestion recovery. In this paper, we present a Cluster Based Congestion Control (CBCC) protocol that consists of scalable and distributed cluster-based mechanisms for supporting congestion control in adhoc networks. The distinctive feature of our approach is that it is based on the self-organization of the network into clusters. The clusters autonomously and proactively monitor congestion within its localized scope .Our protocol consists of clustering mechanism, traffic rate estimation and traffic rate adjustment. By extensive simulation, we show that our CBCC protocol is highly efficient in dealing multiple flows by achieving good delivery ratio and throughput with low delay.
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paper_title: Congestion Avoidance Routing Protocol for QoS-Aware MANETs

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With the increase of multimedia traffic over the past few years and traffic differentiation introduced by IEEE 802.11e, nodes with delay-sensitive multimedia traffic tend to be busy for long periods, thus exacerbating the congestion problem in mobile ad hoc networks (MANETs). Although most of the existing routing protocols are based on the shortest path algorithm, some other metrics like load and delay have also been considered in some other research. In this paper, we first expose that the performance of MANETs routing protocols is highly dependent on the type of traffic generated or routed by intermediate nodes. This paper proposes a Type of service aware routing protocol (TSA), an enhancement to AODV, which uses both the ToS and traditional hop count as route selection metrics. TSA avoids congestion by distributing the load over a potentially greater area and therefore improving spatial reuse. Our simulation study reveals that TSA considerably improves the throughput and packet delay of both low and high priority traffic under different network operational conditions.
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paper_title: A New TCP Congestion Control Mechanism over Wireless Ad Hoc Networks by Router-Assisted Approach

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Due to unawareness of network conditions, regular transmission control protocol (TCP) is not able to fully control the limited resources and distinguish packet loss from congestion loss and random loss. Because of such characteristics, the performance of TCP will be downgraded severely if it runs on wireless networks, such as multi-hop ad hoc networks. In an ad hoc network, nodes play both roles of end system as well as router. We take this advantage to propose a new TCP congestion control mechanism by router-assisted approach. Based on the information feedbacked from routers, a TCP sender is able to adjust its sending speed dynamically in order to avoid overshooting problem. Our proposed protocol has 5-10% higher throughput than TCP NewReno and much less number of retransmissions. The fairness is also achieved while our proposed protocol coexists with other major TCP variants.
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paper_title: Congestion Avoidance Routing Protocol for QoS-Aware MANETs

paper_content:

With the increase of multimedia traffic over the past few years and traffic differentiation introduced by IEEE 802.11e, nodes with delay-sensitive multimedia traffic tend to be busy for long periods, thus exacerbating the congestion problem in mobile ad hoc networks (MANETs). Although most of the existing routing protocols are based on the shortest path algorithm, some other metrics like load and delay have also been considered in some other research. In this paper, we first expose that the performance of MANETs routing protocols is highly dependent on the type of traffic generated or routed by intermediate nodes. This paper proposes a Type of service aware routing protocol (TSA), an enhancement to AODV, which uses both the ToS and traditional hop count as route selection metrics. TSA avoids congestion by distributing the load over a potentially greater area and therefore improving spatial reuse. Our simulation study reveals that TSA considerably improves the throughput and packet delay of both low and high priority traffic under different network operational conditions.
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paper_title: Concordia: An Infrastructure for Collaborating Mobile Agents

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Use of the Internet and the World-Wide-Web has become widespread in recent years and mobile agent technology has proliferated at an equally rapid rate. In this paper, we introduce the Concordia infrastructure for the development and management of network-efficient mobile agent applications for accessing information anytime, anywhere, and on any device.
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paper_title: Agent Tcl: A flexible and secure mobile-agent system

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A mobile agent is an autonomous program that can migrate under its own control from machine to machine in a heterogeneous network. In other words, the program can suspend its execution at an arbitrary point, transport itself to another machine, and then resume execution from the point of suspension. Mobile agents have the potential to provide a {\em single, general framework} in which a wide range of distributed applications can be implemented efficiently and easily. Several challenges must be faced, however, most notably reducing migration overhead, protecting a machine from malicious agents (and an agent from malicious machines), and insulating the agent against network and machine failures. Agent Tcl is a mobile-agent system under development at Dartmouth College that has evolved from a Tcl-only system into a multiple-language system that currently supports Tcl, Java, and Scheme. In this thesis, we examine the motivation behind mobile agents, describe the base Agent Tcl system and its security mechanisms for protecting a machine against malicious agents, and analyze the system''s current performance. Finally, we discuss the security, fault-tolerance and performance enhancements that will be necessary for Agent Tcl and mobile agents in general to realize their full potential.
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paper_title: The Architecture of the Ara Platform for Mobile Agents

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We describe a platform for the portable and secure execution of mobile agents written in various interpreted languages on top of a common run-time core. Agents may migrate at any point in their execution, fully preserving their state, and may exchange messages with other agents. One system may contain many virtual places, each establishing a domain of logically related services under a common security policy governing all agents at this place. Agents are equipped with allowances limiting their resource accesses, both globally per agent lifetime and locally per place. We discuss aspects of this architecture and report about ongoing work.
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paper_title: Aglets: Programming Mobile Agents in Java

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Mobile agents are programs that can be dispatched from one computer and delivered to a remote computer for execution. Arriving at the remote computer, they present their credentials and obtain access to local services and data. They also provide a single uniform paradigm for distributed object computing, encompassing synchrony and asynchrony, message-passing and object-passing, and stationary objects and mobile objects. In this paper, we describe our Java-based mobile agents called Aglets and present its programming interface, called Java Aglet API.
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paper_title: Nomadic control packet-based dynamic route maintenance scheme for adaptive routing in mobile ad hoc networks

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Many novel ideas have been proposed for designing multihop routing protocols in MANET (mobile ad hoc networks). Many of them adopt a method, called flooding, to discover a routing path. In order to increase the over-all routing performance and make optimum use of the limited resources, discovered routing paths need to be dynamically maintained to be continuously optimal in the highly dynamic network topology. However, the flooding is inappropriate for the dynamic route maintenance due to its significant inherent overhead. In this paper, we propose a nomadic control packet (NCP)-based dynamic route maintenance scheme for adaptive routing in MANET. The NCP travels through the network based on a random walk, and collects its stopovers as a traversal record for the purpose of dynamic route maintenance and efficient route discovery. The NCP probabilistically provides nodes with clues to routing path updates by using its traversal record. The nodes can find up-to-date and optimal (less-loaded and shorter) routing path information from the clues, thereby adapting to the dynamic network topology and traffic load conditions. The NCP-based dynamic route maintenance scheme can be easily applied to ad hoc on-demand routing protocols such as AODV and DSR with minimum modifications. In our simulation study we modified the AODV protocol to maintain routing paths using NCPs' traversal record. The simulation results show that the utilization of NCPs helps the routing protocol to notably reduce average end-to-end packet delay with the help of the increased route optimality and traffic congestion control.
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Title: Agent Based Congestion Control Performance in Mobile Ad-Hoc Networks: A Survey

Section 1: Introduction
Description 1: Introduce the concept of ad hoc networks, the importance of mobile ad hoc networks (MANETs), the issue of congestion, and the challenges it presents.

Section 2: Related Works
Description 2: Review and summarize the existing research and methodologies related to congestion control in MANETs, highlighting various approaches and their effectiveness.

Section 3: The Proposed Work
Description 3: Introduce the proposed agent-based congestion control architecture, detailing the classification of traffic, estimation of congestion levels, and prioritization mechanisms.

Section 4: Agent Based Congestion Control Routing
Description 4: Describe the step-by-step process of the agent-based routing mechanism for congestion control, including the calculation and selection of optimal paths.

Section 5: Mobile Agents Technique
Description 5: Explain the concept of mobile agents, their benefits in MANETs, and the general technique of using mobile agents for routing and reducing network load and latency.

Section 6: Routing Using Mobile Agents
Description 6: Discuss early work on routing using mobile agents, focusing on route discovery processes and the associated challenges such as increased network load.

Section 7: Mobile Agent Technology
Description 7: Detail the novel approach of building distributed systems using mobile agent technology, contrasting it with traditional methods.

Section 8: Conclusion
Description 8: Summarize the survey findings, emphasizing the effectiveness of the proposed technique in improving delivery ratio, throughput, and reducing delay.