Network Coded TCP (CTCP) Performance over Satellite Networks

We show preliminary results for the performance of Network Coded TCP (CTCP) over large latency networks. While CTCP performs very well in networks with relatively short RTT, the slow-start mechanism currently employed does not adequately fill the available bandwidth when the RTT is large. Regardless, we show that CTCP still outperforms current TCP variants (i.e., Cubic TCP and Hybla TCP) for high packet loss rates (e.g., >2.5%). We then explore the possibility of a modified congestion control mechanism based off of H-TCP that opens the congestion window quickly to overcome the challenges of large latency networks. Preliminary results are provided that show the combination of network coding with an appropriate congestion control algorithm can provide gains on the order of 20 times that of existing TCP variants. Finally, we provide a discussion of the future work needed to increase CTCP's performance in these networks.Comment: 4 pages, 4 figures, Accepted at SPACOMM 201

Integration of Linux TCP and Simulation: Verification, Validation and Application

Network simulator has been acknowledged as one of the most flexible means in studying and developing protocol as it allows virtually endless numbers of simulated network environments to be setup and protocol of interest to be fine-tuned without requiring any real-world complicated and costly network experiment. However, depending on researchers, the same protocol of interest can be developed in different ways and different implementations may yield the outcomes that do not accurately capture the dynamics of the real protocol. In the last decade, TCP, the protocol on which the Internet is based, has been extensively studied in order to study and reevaluate its performance particularly when TCP based applications and services are deployed in an emerging Next Generation Network (NGN) and Next Generation Internet (NGI). As a result, to understand the realistic interaction of TCP with new types of networks and technologies, a combination of a real-world TCP and a network simulator seems very essential. This work presents an integration of real-world TCP implementation of Linux TCP/IP network stack into a network simulator, called INET. Moreover, verification and validation of the integrated Linux TCP are performed within INET framework to ensure the validity of the integration. The results clearly confirm that the integrated Linux TCP displays reasonable and consistent dynamics with respect to the behaviors of the real-world Linux TCP. Finally, to demonstrate the application of the INET with Linux TCP extension, algorithms of other Linux TCP variants and their dynamic over a large-bandwidth long-delay network are briefly presented

STCP: A New Transport Protocol for High-Speed Networks

Transmission Control Protocol (TCP) is the dominant transport protocol today and likely to be adopted in future high‐speed and optical networks. A number of literature works have been done to modify or tune the Additive Increase Multiplicative Decrease (AIMD) principle in TCP to enhance the network performance. In this work, to efficiently take advantage of the available high bandwidth from the high‐speed and optical infrastructures, we propose a Stratified TCP (STCP) employing parallel virtual transmission layers in high‐speed networks. In this technique, the AIMD principle of TCP is modified to make more aggressive and efficient probing of the available link bandwidth, which in turn increases the performance. Simulation results show that STCP offers a considerable improvement in performance when compared with other TCP variants such as the conventional TCP protocol and Layered TCP (LTCP)

TCP FTAT (Fast Transmit Adaptive Transmission): a New End-To-End Congestion Control Algorithm

Congestion Control in TCP is the algorithm that controls allocation of network resources for a number of competing users sharing a network. The nature of computer networks, which can be described from the TCP protocol perspective as unknown resources for unknown traffic of users, means that the functionality of the congestion control algorithm in TCP requires explicit feedback from the network on which it operates. Unfortunately this is not the way it works with TCP, as one of the fundamental principles of the TCP protocol is to be end-to-end, in order to be able to operate on any network, which can consist of hundreds of routers and hundreds of links with varying bandwidth and capacities. This fact requires the Congestion Control algorithm to be adaptive by nature, to adapt to the network environment under any given circumstances and to obtain the required feedback implicitly through observation and measurements. In this thesis we propose a new TCP end-to-end congestion control algorithm that provides performance improvements over existing TCP congestion control algorithms in computer networks in general, and an even greater improvement in wireless and/or high bandwidth- delay product network

TCP FTAT (Fast Transmit Adaptive Transmission): a New End-To-End Congestion Control Algorithm

Congestion Control in TCP is the algorithm that controls allocation of network resources for a number of competing users sharing a network. The nature of computer networks, which can be described from the TCP protocol perspective as unknown resources for unknown traffic of users, means that the functionality of the congestion control algorithm in TCP requires explicit feedback from the network on which it operates. Unfortunately this is not the way it works with TCP, as one of the fundamental principles of the TCP protocol is to be end-to-end, in order to be able to operate on any network, which can consist of hundreds of routers and hundreds of links with varying bandwidth and capacities. This fact requires the Congestion Control algorithm to be adaptive by nature, to adapt to the network environment under any given circumstances and to obtain the required feedback implicitly through observation and measurements. In this thesis we propose a new TCP end-to-end congestion control algorithm that provides performance improvements over existing TCP congestion control algorithms in computer networks in general, and an even greater improvement in wireless and/or high bandwidth- delay product network

A study of the effects of TCP designs on server efficiency and throughputs on wired and wireless networks.

Yeung, Fei-Fei.Thesis (M.Phil.)--Chinese University of Hong Kong, 2003.Includes bibliographical references (leaves 144-146).Abstracts in English and Chinese.Introduction --- p.1Chapter Part I: --- A New Socket API for Enhancing Server Efficiency --- p.5Chapter Chapter 1 --- Introduction --- p.6Chapter 1.1 --- Brief Background --- p.6Chapter 1.2 --- Deficiencies of Nagle's Algorithm and Goals and Objectives of this Research --- p.7Chapter 1.2.1 --- Effectiveness of Nagle's Algorithm --- p.7Chapter 1.2.2 --- Preventing Small Packets via Application Layer --- p.9Chapter 1.2.3 --- Minimum Delay in TCP Buffer --- p.10Chapter 1.2.4 --- Maximum Delay in TCP Buffer --- p.11Chapter 1.2.5 --- New Socket API --- p.12Chapter 1.3 --- Scope of Research and Summary of Contributions --- p.12Chapter 1.4 --- Organization of Part 1 --- p.13Chapter Chapter 2 --- Background --- p.14Chapter 2.1 --- Review of Nagle's Algorithm --- p.14Chapter 2.2 --- Additional Problems Inherent in Nagle's Algorithm --- p.17Chapter 2.3 --- Previous Proposed Modifications on Nagle's Algorithm --- p.22Chapter 2.3.1 --- The Minshall Modification --- p.22Chapter 2.3.1.1 --- The Minshall Modification --- p.22Chapter 2.3.1.2 --- The Minshall et al. Modification --- p.23Chapter 2.3.2 --- The Borman Modification --- p.23Chapter 2.3.3 --- The Jeffrey et al. Modification --- p.25Chapter 2.3.3.1 --- The EOM and MORE Variants --- p.25Chapter 2.3.3.2 --- The DLDET Variant --- p.26Chapter 2.3.4 --- Comparison Between Our Proposal and Related Works --- p.26Chapter Chapter 3 --- Min-Delay-Max-Delay TCP Buffering --- p.28Chapter 3.1 --- Minimum Delay --- p.29Chapter 3.1.1 --- Why Enabling Nagle's Algorithm Alone is Not a Solution? --- p.29Chapter 3.1.2 --- Advantages of Min-Delay TCP-layer Buffering versus Application-layer Buffering --- p.30Chapter 3.2 --- Maximum Delay --- p.32Chapter 3.2.1 --- Why Enabling Nagle's Algorithm Alone is Not a Solution? --- p.32Chapter 3.2.2 --- Advantages of Max-delay TCP Buffering versus Nagle's Algorithm --- p.33Chapter 3.3 --- Interaction with Nagle's Algorithm --- p.34Chapter 3.4 --- When to Apply Our Proposed Scheme? --- p.36Chapter 3.5 --- New Socket Option Description --- p.38Chapter 3.6 --- Implementation --- p.40Chapter 3.6.1 --- Small Packet Transmission Decision Logic --- p.42Chapter 3.6.2 --- Modified API --- p.44Chapter Chapter 4 --- Experiments --- p.46Chapter 4.1 --- The Effect of Kernel Buffering Mechanism on the Service Time --- p.47Chapter 4.1.1 --- Aims and Methodology --- p.47Chapter 4.1.2 --- Comparison of Transmission Time Required --- p.49Chapter 4.2 --- Performance of Min-Delay-Max-Delay Scheme --- p.56Chapter 4.2.1 --- Methodology --- p.56Chapter 4.2.1.1 --- Network Setup --- p.56Chapter 4.2.1.2 --- Traffic Model --- p.58Chapter 4.2.1.3 --- Delay Measurement --- p.60Chapter 4.2.2 --- Efficiency of Busy Server --- p.62Chapter 4.2.2.1 --- Performance of Nagle's algorithm --- p.62Chapter 4.2.2.2 --- Performance of Min-Delay TCP Buffering Scheme --- p.67Chapter 4.2.3 --- Limiting Delay by Setting TCP´ؤMAXDELAY --- p.70Chapter 4.3 --- Performance Sensitivity Discussion --- p.77Chapter 4.3.1 --- Sensitivity to Data Size per Invocation of send() --- p.77Chapter 4.3.2 --- Sensitivity to Minimum Delay --- p.83Chapter 4.3.3 --- Sensitivity to Round Trip Time --- p.85Chapter Chapter 5 --- Conclusion --- p.88Chapter Part II: --- Two Analytical Models for a Refined TCP Algorithm (TCP Veno) for Wired/Wireless Networks --- p.91Chapter Chapter 1 --- Introduction --- p.92Chapter 1.1 --- Brief Background --- p.92Chapter 1.2 --- Motivation and Two Analytical Models --- p.95Chapter 1.3 --- Organization of Part II --- p.96Chapter Chapter 2 --- Background --- p.97Chapter 2.1 --- TCP Veno Algorithm --- p.97Chapter 2.1.1 --- Packet Loss Type Identification --- p.97Chapter 2.1.2 --- Refined AIMD Algorithm --- p.99Chapter 2.1.2.1 --- Random Loss Management --- p.99Chapter 2.1.2.2 --- Congestion Management --- p.100Chapter 2.2 --- A Simple Model of TCP Reno --- p.101Chapter 2.3 --- Stochastic Modeling of TCP Reno over Lossy Channels --- p.103Chapter Chapter 3 --- Two Analytical Models --- p.104Chapter 3.1 --- Simple Model --- p.104Chapter 3.1.1 --- Random-loss Only Case --- p.105Chapter 3.1.2 --- Congestion-loss Only Case --- p.108Chapter 3.1.3 --- The General Case (Random + Congestion Loss) --- p.110Chapter 3.2 --- Markov Model --- p.115Chapter 3.2.1 --- Congestion Window Evolution --- p.115Chapter 3.2.2 --- Average Throughput Formulating --- p.119Chapter 3.2.2.1 --- Random-loss Only Case --- p.120Chapter 3.2.2.2 --- Congestion-loss Only Case --- p.122Chapter 3.2.2.3 --- The General Case (Random + Congestion Loss) --- p.123Chapter Chapter 4 --- Comparison with Experimental Results and Discussions --- p.127Chapter 4.1 --- Throughput versus Random Loss Probability --- p.127Chapter 4.2 --- Throughput versus Normalized Buffer Size --- p.132Chapter 4.3 --- Throughput versus Bandwidth in Asymmetric Networks --- p.135Chapter 4.3 --- Summary --- p.136Chapter Chapter 5 --- Sensitivity of TCP Veno Throughput to Various Parameters --- p.137Chapter 5.1 --- Multiplicative Decrease Factor (α) --- p.137Chapter 5.2 --- Number of Backlogs (β) and Fractional Increase Factor (γ) --- p.139Chapter Chapter 6 --- Conclusions --- p.142Bibliography --- p.14

Novel methods of utilizing Jitter for Network Congestion Control

This paper proposes a novel paradigm for network congestion control. Instead of perpetual conflict as in TCP, a proof-of-concept first-ever protocol enabling inter-flow communication without infrastructure support thru a side channel constructed on generic FIFO queue behaviour is presented. This enables independent flows passing thru the same bottleneck queue to communicate and achieve fair capacity sharing and a stable equilibrium state in a rapid fashion