This tutorial has been written by the FDDI Consortium of the InterOperability Lab at the University of New Hampshire. The purpose of this tutorial is to provide basic information about FDDI, a networking protocol used in Local Area Networks.

FDDI (Fiber Distributed Data Interface) has found its niche as a reliable, high-speed backbone for mission critical and high traffic networks. It can transport data at a rate of 100 megabits per second, and can support up to 500 stations on a single network. FDDI was designed to run through fiber cables, transmitting light pulses to convey information between stations, but it can also run on copper using electrical signals.

FDDI is highly reliable because FDDI networks consist of two counter-rotating rings. A secondary ring provides an alternate data path in the event a fault occurs on the primary ring. FDDI stations incorporate this secondary ring into the data path to route traffic around the fault.