FDDI

Overview
FDDI (Fiber Distributed Data Interface) is a 100 Mbit/sec optical data transmission standard for local area networks (LANs). FDDI uses a token-ring structure, but uses the IEEE802.4 token-bus times-token protocol instead of the traditional IEE802.5 token-ring protocol.

While FDDI is intended for fiber optic lines, it is a standard, and not limited to fiber optics and can use normal conductive lines.