Optically interconnecteddistributed shared memory(OIDSM) systems offer significant performance advantages due to the fast interconnection network. The photonic network of the proposed approach is based on a wavelength‐division multiplexed (WDMA) passive star‐coupled configuration.Optical self‐routingwhich partitions the traffic and relaxes the design constraints on the receiver subsystem is achievable since a node now only receives and processes a fraction of the network traffic. A major concern with the multi‐access approach is that a media access control and a cache coherence protocol are required to provide access to a distributed arbitration of the WDMA photonic network. In particular, one class of media access protocol (TDMA‐C) requires a control channel to broadcast reservation requests. The broadcast capability is also able to support coherence level control signals such as invalidations which enable a snooping based coherence protocol. The object of this paper is to evaluate how OIDSM can ease the traffic in large‐scale snooping‐based shared memory multiprocessors. A semi‐Markov model‐is developed to study the performance of OIDSM. The analytical model has been validated by extensive simulation and evaluates the performance by varying the system's parameters.