Implementing a space priority mechanism in a cell-rate ATM network simulator

Asynchronous Transfer Mode (ATM) provides the means of transporting information from traffic sources with different characteristics (such as tolerances to cell loss, delay and burstiness) through a broadband network. In order to optimise the network utilisation, while meeting the requirements of each type of traffic source, it is possible to use space priority mechanisms. This paper describes one such mechanism, called partial buffer sharing, and its implementation. Cell-rate simulation models burst-scale queueing, i.e., when input rate exceeds service rate. The approximation model for partial buffer sharing is to assume that the queue size above the threshold is zero. In practice, space above the threshold caters for cell scale queuing which is not modelled by cell-rate simulation. This approximation considerably simplifies the implementation, and only affects results for high priority traffic