FDDI definition
Fiber Distributed Data Interface (FDDI) is an obsolete collection of ANSI and ISO standards for the high-speed transmission of data using fiber-optic cables. FDDI networks operate at a maximum speed of 100 Mbps and can span distances of up to 200 kilometers (or 124 miles).
See also: ring network, network frame
History of FDDI
FDDI was developed in the 1980s to provide high-speed internet over a wider geographical area than a typical local area network (LAN). From its introduction to the mid-1990s, FDDI was a popular choice for campus backbone networks due to the slow speed of the alternatives.
FDDI originally envisioned fiber-optic cables as the primary physical medium, but later revisions made the standards compatible with copper cables. When FDDI is applied to copper cable networks, it is often referred to as CDDI (copper distributed data interface).
In the present day, FDDI has been largely replaced by Fast Ethernet (which offers the same speed at a lower cost) and Gigabit Ethernet (which is faster, cheaper, and more widespread).
FDDI topology
FDDI uses a token-passing ring topology, where tokens (digital signals that control access to the network and data transmission rights) and data travel in a circular fashion around the network. When a device wants to transmit data, it captures the token and sends the data to the ring.
FDDI topology is typically built as a “dual rings of trees” — host computers are attached to an infrastructure device (such as a router, concentrator, or dual attachment station), which is attached to both of the rings in the topology.
