Search for a command to run...
The presence of scaling behavior in telecommunications traffic is striking not only in its ubiquity, appearing in almost every kind of packet data, but also in the wide range of scales over which the scaling holds. It is rare indeed that a physical phenomenon obeys a consistent law over so many orders of magnitude. This may well extend further, as increases in network bandwidth over time progressively "reveal" higher scales. While the presence of scaling is now well established, its impact on teletraffic issues and network performance is still the subject of some confusion and uncertainty. This chapter shows that a difficult problem arises when simulating systems with heavy-tailed workloads. In such systems, steady-state behavior can be elusive, because average-case behavior depends on the presence of many small observations as well as a few large observations. This problem has two implications. First, since a number of large but rare observations must occur before average-case behavior is evident, convergence of a simulation to steady state may be slow. It may not be possible in any reasonable time to achieve steady state. Second, since many small observations must occur to balance the presence of large observations, large observations can have a dominating effect on performance results even at steady state. Simulations may still behave erratically even at steady state.