STATIONARY INCREMENTS OF ACCUMULATION PROCESSES IN QUEUES AND GENERALIZED SEMI-MARKOV SCHEMES

Let T(x) be the length of time to accumulate x units of a resource. In queueing, the resource could be service. We derive a sufficient condition for the process (T(x),x greater-than-or-equal-to 0) to have stationary increments where T(x) is an additive functional of a Markov process. This condition is satisfied in symmetric queues and generalized semi-Markov schemes with insensitive components. As a corollary, we show that the conditional expected response time in a symmetric queue is linear in the service requirement. A similar result holds for the conditional average residence time of an insensitive component in a GSMS.