I-Shyan Hwang and Patrick W. Dowd*
Department of Electronic Engineering
Van-Nung Institute of Technology and Commerce
Chung-Li, Taiwan, 320, R.O.C.
*Department of Electrical and Computer Engineering
State University of New York at Buffalo
Buffalo, N.Y. 14260
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 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 (I-SA) is compared to an approach based on interleaved time multiplexing (I-TDMA). 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 while varying the optical switching latency, the number of nodes, and the wavelength channels.
Keywords: distributed shared memory, photonic networks, wavelength division multiple access, performance analysis, media access protocol
Received January 15, 1994; revised November 22, 1994.
Communicated by Shing-Tsaan Huang.