FDDI stands for Fiber Distributed Data Interface. FDDI standard was developed by ANSI,
the American National Standards Institute. It is based on the use of double optical fiber cable
and provides for a token-passing ring configuration, operating at 100 Mbps.
FDDI is being developed to deal with the requirements of high-speed LANs, MANs and
backbone networks. Since FDDI consists of two fiber rings, primary and secondary ring,
there is good redundancy and high availability. Normally traffic only flows on the primary
ring, but if the primary ring is broken then the secondary ring is used.