Routing in interconnected FDDI LANs

The fibre distributed data interface is a recently standardised, 100 Mbps local area network using fibre optic technology. FDDI is capable of supporting up to 500 users over a 100 km distance. As FDDI becomes widely accepted and implemented the need for interconnecting remote FDDI LANs becomes increasingly important. FDDI interconnection can be accomplished in several different ways. Methods include connection by single mode fibre, metropolitan area network technology (DQDB) or via leased lines using bridges and routers. The paper considers the case of a relatively large corporate network composed of FDDI LANs which are separated by large distances. The best solution, in terms of economics and performance, for such a network involves leased lines and layer 3 routers. A modified extension to a Bellman-Ford routing algorithm is simulated and its performance examined