The entropy of traffic streams in ATM virtual circuits

The authors model an ATM virtual circuit as a tandem queueing system. At each queue, transmission of the virtual circuit traffic is interrupted by cross traffic, causing the scattering and coalescing of cells. They study this phenomenon using entropy as a traffic descriptor. They compute the entropy of traffic streams produced in simulation, via an estimation technique based on the Lempel-Ziv universal data compression method. The estimator modifies the Lempel-Ziv method to compute entropy rather than compress data. They show that the entropy of virtual circuit traffic at successive queues can either increase or decrease depending upon the types of input traffic. Even when bursty input is scattered, its entropy does not achieve maximum entropy within a reasonable number of queues. They also define a distance metric to compare the correlation structures of two output processes and observe this metric at successive queue outputs