Fiber Distributed Data Interface
Fiber Distributed Data Interface (FDDI) is a standard for data transmission in a local area network. It uses optical fiber as its standard underlying physical medium, although it was also later specified to use copper cable, in which case it may be called CDDI (Copper Distributed Data Interface), standardized as TP-PMD (Twisted-Pair Physical Medium-Dependent), also referred to as TP-DDI (Twisted-Pair Distributed Data Interface).
"FDDI" redirects here. For the Indian educational institute, see Footwear Design and Development Institute.FDDI was effectively made obsolete in local networks by Fast Ethernet which offered the same 100 Mbit/s speeds, but at a much lower cost and, from 1998 on, by Gigabit Ethernet due to its speed, even lower cost, and ubiquity.[1]
Description[edit]
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).[2] Although FDDI logical topology is a ring-based token network, it did not use the IEEE 802.5 Token Ring protocol as its basis; instead, its protocol was derived from the IEEE 802.4 token bus timed token protocol. In addition to covering large geographical areas, FDDI local area networks can support thousands of users. FDDI offers both a Dual-Attached Station (DAS), counter-rotating token ring topology and a Single-Attached Station (SAS), token bus passing ring topology.[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. The standards process started in the mid 1980s.[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.[5] Work started to connect FDDI networks to synchronous optical networking (SONET) technology.
An FDDI network contains two rings, one as a secondary backup in case the primary ring fails. The primary ring offers up to 100 Mbit/s capacity. When a network has no requirement for the secondary ring to do backup, it can also carry data, extending capacity to 200 Mbit/s. The single ring can extend the maximum distance; a dual ring can extend 100 km (62 mi). FDDI had a larger maximum frame size (4,352 bytes) than the standard Ethernet family, which only supports a maximum frame size of 1,500 bytes,[a] allowing better effective data rates in some cases.
Deployment[edit]
FDDI was considered an attractive campus backbone network technology in the early to mid 1990s since existing Ethernet networks only offered 10 Mbit/s data rates and Token Ring networks only offered 4 Mbit/s or 16 Mbit/s rates. Thus it was a relatively high-speed choice of that era, with speeds such as 100 Mbit/s.
By 1994, vendors included Cisco Systems, National Semiconductor, Network Peripherals, SysKonnect (acquired by Marvell Technology Group), and 3Com.[10]
FDDI installations have largely been replaced by Ethernet deployments.[1]
FDDI standards included:[11]