Recent measurements of local-area and wide-area traf®c [8, 28, 42] have shown that network traf®c exhibits variability at a wide range of scales. What is striking is the ubiquitousness of the phenomenon, which has been observed in diverse networking contexts, from Ethernet to ATM, LAN and WAN, compressed video, and HTTPbased WWW traf®c [8, 15, 23, 42]. Such scale-invariant variability is in strong contrast to traditional models of network traf®c, which show burstiness at short time scales but are essentially smooth at large time scales; that is, they lack long-range dependence. Since. | Self-Similar Network Traffic and Performance Evaluation Edited by Kihong Park and Walter Willinger Copyright 2000 by John Wiley Sons Inc. Print ISBN 0-471-31974-0 Electronic ISBN 0-471-20644-X 18 CONGESTION CONTROL FOR SELF-SIMILAR NETWORK TRAFFIC Tsunyi Tuan and Kihong Park Network Systems Lab Department of Computer Sciences Purdue University West Lafayette LN 47907 INTRODUCTION Recent measurements of local-area and wide-area traffic 8 28 42 have shown that network traffic exhibits variability at a wide range of scales. What is striking is the ubiquitousness of the phenomenon which has been observed in diverse networking contexts from Ethernet to ATM LAN and WAN compressed video and HTTPbased WWW traffic 8 15 23 42 . Such scale-invariant variability is in strong contrast to traditional models of network traffic which show burstiness at short time scales but are essentially smooth at large time scales that is they lack long-range dependence. Since scale-invariant burstiness can exert a significant impact on network performance understanding the causes and effects of traffic self-similarity is an important problem. In previous work 33 34 we have investigated the causal and performance aspects of traffic self-similarity and we have shown that self-similar traffic flow is an intrinsic property of networked client server systems with heavy-tailed file size distributions and conjoint provision of low delay and high throughput is adversely affected by scale-invariant burstiness. From a queueing theory perspective the principal distinguishing characteristic of long-range-dependent LRD traffic is that the queue length distribution decays much more slowly that is polynomially vis-à-vis short-range-dependent SRD traffic sources such as Poisson sources which exhibit exponential decay. A number of performance studies 1 2 11 29 32 34 447 448 CONGESTION CONTROL FOR SELF-SIMILAR NETWORK TRAFFIC have shown that self-similarity has a detrimental effect on network performance .
