The authors consider a queuing system with a finite buffer and multiple heterogeneous arrival streams. They focus on Markov modulated arrival processes with different burstings and investigate the loss of individual arrival streams when the parameters of the heterogeneous arrival streams are varied. The analysis includes both continuous-time and discrete-time treatments of multiplexed heterogeneous Markov modulated arrivals. Loss probabilities are derived for a priority packet discarding scheme. A new characterization of an arrival stream is introduced, referred to as a self-loss, and it is used to qualitatively predict the effects of multiplexing bursty streams with nonbursty streams. The effectiveness of priority packet discarding is also investigated through numerical examples.>

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.>

The authors survey a number of important research topics in ATM (asynchronous transfer mode) networks. The topics covered include mathematical modeling of various types of traffic sources, congestion-control and error-control schemes for ATM networks, and priority schemes to support multiple classes of traffic. Standard activity for ATM networks and future research problems in ATM are also presented. It is shown that the cell-arrival process for data sources can be modeled by a simple Poisson process. However, voice sources or video sources require more complex processes because of the correlation among cell arrivals. Due to the effects of high-speed channels, preventive control is more effective in ATM networks than reactive control. Due to the use of optical fibers in ATM networks, the channel error rate is very small. The effects of propagation delay and processing time become significant in such high-speed networks. These fundamental changes trigger the necessity to reexamine the error-control schemes used in existing networks. Due to the diversity of service and performance requirements, the notion of multiple traffic classes is required, and separate control mechanisms should be used according to the traffic classes. The priority scheme is shown to be an effective method to support multiple classes of traffic.>

A discussion is presented of the robustness of the Capetanakis collision resolution algorithm for multiple-access networks. In particular, they show that the algorithm is robust against errors that cause different stations to see different feedback information on the results of the transmission attempts, and they quantify, using simulation, the performance (throughput/delay) degradation caused by those unshared errors.>