Fiber Distributed Data Interface

[1] FDDI provides a 100 Mbit/s optical standard for data transmission in local area network that can extend in length up to 200 kilometers (120 mi).

[3] FDDI, as a product of American National Standards Institute X3T9.5 (now X3T12), conforms to the Open Systems Interconnection (OSI) model of functional layering using other protocols.

[4] FDDI-II, a version of FDDI described in 1989, added circuit-switched service capability to the network so that it could also handle voice and video signals.

Typically, a computer-room contained the whole dual ring, although some implementations deployed FDDI as a metropolitan area network.

The standard actually allows for optical bypasses, but network engineers consider these unreliable and error-prone.

Devices such as workstations and minicomputers that might not come under the control of the network managers are not suitable for connection to the dual ring.

By 1994, vendors included Cisco Systems, National Semiconductor, Network Peripherals, SysKonnect (acquired by Marvell Technology Group), and 3Com.