LIGHTNING-a WDM based distributed shared memory clustering testbed: network and physical layer

LIGHTNING is a scalable distributed shared memory computation system based on powerful workstations interconnected together via a high speed WDM optical bus with direct access to the memory of the workstations. This system supports high-performance I/O-both interprocessor communication and remote filesystem access-by using a high speed WDM optical backbone. The optical interconnections combine wavelength, space, and time-multiplexing techniques. The chosen interconnection architecture is hierarchical and achieves low latency and high throughput. Wavelengths are re-used at each level of the hierarchy through spatial multiplexing by adaptable wavelength routers. The system is dynamically reconfigurable through the wavelength routers and therefore can dynamically vary the bandwidth allocated to different levels of the hierarchy. Single-hop communication is achieved through allowing a packet to remain in the optical form from source to destination, without requiring cross-dimensional intermediate routing