LIGHTNING-a WDM-based distributed shared memory clustering testbed: system architecture and protocols

This presentation describes a hierarchical optical structure for high-performance processor clustering. The architecture is based on wavelength division multiplexing (WDM) which enables multiple multi-access channels to be realized on a single optical fiber. The objective of the hierarchical architecture is to achieve scalability yet avoid the requirement of multiple wavelength tunable devices per node. Furthermore, single-hop all-optical communication is achieved: a packet remains in the optical form from source to destination and does not require intermediate routing or o/e conversion. The wavelength multiplexed hierarchical structure features wavelength channel re-use at each level, allowing scalability to very large system sizes. It partitions the traffic between different levels of the hierarchy without electronic intervention in a combination of wavelength- and space-division multiplexing. A significant advantage of the proposed structure is its ability to dynamically vary the bandwidth provided to different levels of the hierarchy