Media Access Protocol Impact on a WDMA Passive Star Photonic Network with Distributed Shared Memory System

Abstract This paper develops a performance model of an optically interconnected parallel computer system operating in a distributed shared memory environment. The performance model is developed to reflect the impact of low level optical media access control and optical device switching latency on high level system performance. The photonic network is based on a passive star-coupled structure that exhibits optical self-routing through wavelength division multiple access channels. The performance of a generalized random access protocol is compared to an approach based on interleaved time multiplexing. Both protocols are designed to operate in a multiple-channel multiple-access environment and require each node to possess a wavelength tunable transmitter and a fixed (or slow tunable) receiver. A semi-markov model has been developed to study the interaction of the distributed shared memory architecture and investigate the performance of the two protocols with the photonic network. This analytical model has been validated by extensive simulation. The model is then used to examine the system performance with varying number of nodes and wavelength channels.