Dynamics of an Explicit Rate Allocation Algorithm for ATM Networks

In this paper we study the performance of an explicit rate allocation algorithm for ATM networks using the available bit-rate (ABR) class of service. We examine the behavior of ABR traffic with simple cell sources, and demonstrate that the allocation algorithm is fair and maintains network efficiency in a variety of network configurations. We also study the behavior of TCP/IP sources using ABR service in a network of switches employing the rate allocation algorithm; the results show substantial improvements in fairness and efficiency in comparison with the performance of TCP in an underlying datagram-based network. We study the performance of ABR traffic in the presence of higher-priority variable bitrate (VBR) video traffic and show that the overall system achieves high utilization with modest queue sizes in the switches, and the ABR flows adapt to the available rate in a fairly short interval. We also demonstrate the scalability of the rate allocation algorithm with respect to the nu..

Indicators for the Assessment of Congestion in TCP over ATM-UBR

In this paper we analyse congestion in TCP over ATM-UBR, in particular the association between the congestion measures at the ATM physical and TCP transport layers. Two new indicators, protocol level congestion association factor (PLCAF) and CLR-PRR correlation coefficient are used. ATM cell loss ratio (CLR) and TCP packet retransmission ratio (PRR) are good measures of congestion at their respective layers, but do not address the relation between cell loss and its effect on TCP congestion control schemes. Both PLCAF and CLR-PRR correlation coefficient are derived to better capture the association between congestion measures at ATM and TCP levels. It is shown through simulation of multiple TCP connections over a ATM-UBR service under selected number of different operating conditions that the two new indicators can be successfully used for the analysis of congestion in TCP over ATM-UBR. Keywords: TCP, ATM, congestion association, correlation coefficient 1 This work is partially funde..

An efficient rate allocation algorithm for ATM networks providing max-min fairness

We describe a new algorithm for rate allocation within the individual switches of an ATM network implementing a rate-based congestion control algorithm for Available Bit-Rate (ABR) traffic. The algorithm performs an allocation in \Theta(1) time, allowing it to be applied to ATM switches supporting a large number of virtual circuits. When the total available capacity or the requests of the individual connections change, the algorithm converges to the max-min allocation. Results from simulations using ATM sources show that the algorithm provides close to ideal throughput and converges to the max-min fair allocation rapidly when the available bandwidth or the individual requests change. Keywords Rate control, max-min fairness, ATM congestion control Supported by the Advanced Research Projects Agency (ARPA) under Contract No. F19628-93-C-0175 and by the NSF Young Investigator Award No. MIP-9257103. 1 INTRODUCTION Broadband packet networks based on Asynchronous Transfer Mode (ATM) are..