A Multi-Level WDM Access Protocol for an Optically Interconnected Parallel Computer

Scalable, hierarchical, all-optical, WDM networks for processor interconnection have been recently considered. This paper introduces an access protocol for this type of network which supports a distributed shared memory environment. The objectives of the protocol are reduced average latency per packet, support of broadcast/multicast, collisionless communication, and the exploitation of the inherent distributed shared memory traffic characteristics. A hybrid strategy, in terms of channel reservation, is described that trades maximum capacity for reducedcommunication latency to improve system response. The performance of the protocol is analyzed through analytic and simulation models with varying system parameters such as number of nodes and channels. The performance of the new protocol is compared to a TDM-based protocol and their relative merits and demerits are examined.