Approximations for performance evaluation of the packet access queue in QPSX: The IEEE 802.6 evolving MAN standard

QPSX is a hybrid switching system. In this paper, we suggest several approximations which can be used to evaluate the performance of the packet access queue in QPSX for three implementations: unlimited buffer, limited buffer and interactive environment. Two circuit allocation policies, namely, repacking and first-fit, are considered. The queueing statistics are obtained by modeling the packet queue as a queue in a random environment with slowly varying service rates.