Evaluation Study for Delay and Link Utilization with the New-Additive Increase Multiplicative Decrease Congestion Avoidance and Control Algorithm

As the Internet becomes increasingly heterogeneous, the issue of congestion avoidance and control becomes ever more important. And the queue length, end-to-end delays and link utilization is some of the important things in term of congestion avoidance and control mechanisms. In this work we continue to study the performances of the New-AIMD (Additive Increase Multiplicative Decrease) mechanism as one of the core protocols for TCP congestion avoidance and control algorithm, we want to evaluate the effect of using the AIMD algorithm after developing it to find a new approach, as we called it the New-AIMD algorithm to measure the Queue length, delay and bottleneck link utilization, and use the NCTUns simulator to get the results after make the modification for the mechanism. And we will use the Droptail mechanism as the active queue management mechanism (AQM) in the bottleneck router. After implementation of our new approach with different number of flows, we expect the delay will less when we measure the delay dependent on the throughput for all the system, and also we expect to get end-to-end delay less. And we will measure the second type of delay a (queuing delay), as we shown in the figure 1 bellow. Also we will measure the bottleneck link utilization, and we expect to get high utilization for bottleneck link with using this mechanism, and avoid the collisions in the link

Optimization flow control -- I: Basic algorithm and convergence

We propose an optimization approach to flow control where the objective is to maximize the aggregate source utility over their transmission rates. We view network links and sources as processors of a distributed computation system to solve the dual problem using a gradient projection algorithm. In this system, sources select transmission rates that maximize their own benefits, utility minus bandwidth cost, and network links adjust bandwidth prices to coordinate the sources' decisions. We allow feedback delays to be different, substantial, and time varying, and links and sources to update at different times and with different frequencies. We provide asynchronous distributed algorithms and prove their convergence in a static environment. We present measurements obtained from a preliminary prototype to illustrate the convergence of the algorithm in a slowly time-varying environment. We discuss its fairness property

Congestion Control and Traffic Management in ATM Networks: Recent Advances and A Survey

Congestion control mechanisms for ATM networks as selected by the ATM Forum traffic management group are described. Reasons behind these selections are explained. In particular, selection criteria for selection between rate-based and credit-based approach and the key points of the debate between the two approaches are presented. The approach that was finally selected and several other schemes that were considered are described.Comment: Invited submission to Computer Networks and ISDN System

TCP/IP traffic over ATM network with ABR flow and congestion control

Most traffics over the existing ATM network are generated by applications running over TCP/IP protocol stack. In the near future, the success of ATM technology will depend largely on how well it supports the huge legacy of existing TCP/IP applications. In this thesis, we study and compare the performance of TCP/IP traffic running on different rate based ABR flow control algorithms such as EFCI, ERICA and FMMRA by extensive simulations. Infinite source-end traffic behavior is chosen to represent, FTP application running on TCP/IP. Background VBR traffic with different ON-OFF frequency is introduced to produce transient network states as well as congestion. The simulations produce many insights on issues such as: ABR queue length in congested ATM switch, source-end ACR (Allowed Cell Rate), link utilization at congestion point, efficient end to end TCP throughput, the TCP congestion control window size, and the TCP round trip time. Based on the simulation results, zero cell loss switch buffer requirement of the three algorithms are compared, and the fairness of ABR bandwidth allocation among TCP connections are analyzed. The interaction between the TCP layer and the ATM layer flow and congestion control mechanism is analyzed. Our simulation results show that in order to get a good TCP throughput and affordable switch buffer requirement, some kind of switch queue length monitoring and control mechanism is necessary in the ABR. congestion algorithm