Fiber Distributed Data Interface3-15Technology BasicsSpecial Design Considerations• The orderly progression of transmission and reception throughout the TokenRing allows special fault identifications and automatic correction features to bebuilt into the technology.• There are limitations to the number of stations on a ring and the distances towhich cabling can be run. These limitations change according to the type ofcable used, the speed of the network, and a number of other factors.Fiber Distributed Data InterfaceAbstractFiber Distributed Data Interface, or FDDI, is a high-speed networking technologywhich provides a maximum available throughput of 100 Mbps. Due to its highspeed and fault-tolerance, it is often used to connect slower workgroup LANs toone another.The first portions of an FDDI standard were ratified in 1988 by the AmericanNational Standards Institute, or ANSI. The FDDI Working Group, X3T9.5, forwhom the FDDI standard is named, have continued to release specifications andupdates to make the FDDI technology more accessible and capable for networkoperations. Recently, additional specifications have been ratified and publishedwhich detail the use of transmission media other than fiber optics for FDDInetworking. For more information on the standard media which may be used inan FDDI network, see Chapters 7 and 10.TheoryFDDI LANs operate under the same basic principles as Token Ring networks. Theoperating network provides regular opportunities for stations to transmitinformation, and each station can expect to receive network data at regularintervals. A specialized frame of information, also called a token, is passed fromone station to another, traversing the ring in a pre-set amount of time. No stationmay transmit unless it has received and “claimed” the token.
