THE FDDI PILOT PROJECT IN COMPUTER SCIENCE AT THE UNIVERSITY OF CALGARY

Abstract

Continued demands on the Computer Science Department's resources forced an unsatisfactory network topology. Sun Microsystem's implementation of FDDI was selected to replace the backbone, and is the first such installation in Western Canada. The paper reviews the hardware, software and topology of FDDI systems, explains the configuration chosen for the department, and discusses the installation. Each ring node requires a VME bus FDDI controller board. Physically the ring is star connected, providing convenient patch panel reconfiguration for maintenance and testing. All department file/client servers were attached to the ring, while groups of client workstations are controlled over sub-Ethernets. The resulting topology is a central backbone ring, with sub-Ethernets radiating from each FDDI node. FDDI's simplicity enables performance improvements in addition to the increased speed, so long as the network topology and systems configuration are carefully designed. Reliability is achieved by duplication of file systems on all ring nodes, so that any subnetwork may operate independently of the ring. We conclude by recommending that machine crashes should cause the FDDI board to pass through the data, rather than wrapping the dual rings and possibly causing unnecessary ring fragmentation. The paper discusses the relative merits of concentrators and optical bypass switches for fragmentation protection.