THE SUPERCOMPUTER SUPERNET TESTBED - A WDM-BASED SUPERCOMPUTER INTERCONNECT

Current fiber optic networks effectively provide local connectivity am ong end user computing devices, and can serve as backbone fabric betwe en LAN subnets across campus and metropolitan areas, However, combinin g both stream service (in which ATM excels) and low latency datagram s ervice (in which cluster networks like Myrinet and POLO excel) has bee n difficult to realize, This paper describes a new wavelength division multiplexed (WDM) fiber optic network that supports both stream and d atagram service and extends reach and functionality of low-latency, hi gh bandwidth workstation clusters to a campus and MAN setting, The nov el concept is based on combining the rich interconnect structure of WD M fiber optics with the fast, low-latency mesh of crossbar switches re cently developed for workstation groups, This system, called the Super computer Supernet (SSN) achieves a high level of performance by replac ing the point-to-point copper wire links with a parallel channel (WDM) fiber optic interconnect system, The novel scheme interconnects async hronous wormhole routing switches used in parallel supercomputers via multi-channel WDM fiber optic links embedded in to an optical star (or tree) ''physical'' topology, WDM will be used to subdivide the very l arge fiber bandwidth into several channels, each of Gb/s bandwidth, WD M channels (supporting also time division multiplexing) will be establ ished between modules, thus defining a dense ''virtual'' interconnecti on topology, which is dynamically reconfigurable and responds to chang ing traffic patterns, A pool of channels will be set aside for direct, end-to-end connections between crossbars, providing circuit-switched service for real-time traffic applications.