Fiber Distributed Data Interface, FDDI

- Apr 17, 2020-

Fiber Distributed Data Interface, FDDI



Optical fiber distributed data interface FDDI is a high-speed backbone network that uses optical fiber as a transmission medium. It can be used to interconnect a single computer with a local area network.

The FDDI standard adopts the IEEE802 architecture and LLC protocol, studies the FDDI's own MAC protocol, and proposes a physical layer medium related (Physical Layer Medium Dependent, PMD) sublayer and a physical layer protocol (PHY) at the physical layer. Sublayer. In 1992, the research on the interface standard of FDDI and SONET interconnection was completed.

FDDI is specially designed for data transmission. In order to transmit voice, image and video services, the FDDI-II standard will be extended from FDDI basic mode (Basic Mode) supporting packet switching to hybrid mode (Hybrid Mode). The mixed mode can simultaneously support packet switching and circuit switching. Currently, the next-generation FDDI standard under study is called FFOL (FDDI Follow-On LAN).


Fiber Distributed Data Interface,FDDI


In essence, FDDI is composed of four sub-parts, each part has its own specific function. The combination of the various parts enables FDDI to provide high-speed connections between upper layer protocols (such as TCP / IP, IPX) and media (such as optical cables).

The four sub-specifications of FDDI are media access control (MAC), physical layer protocol layer (PHY), physical medium related layer (PMD), and station management (SMT). MAC specifies how to access the medium, including the frame format, addressing, token processing, cyclic redundancy check algorithm (CRC), and error recovery mechanism required by the protocol; PHY specifies the transmission encoding and decoding procedures, clock requirements, and other functions ; PMD stipulates the characteristics that the transmission medium should have, including fiber-optic link (Fiber-optic Link), power level (Power Level), bit error rate (Bit-error Rate), fiber optic device (Optical Component) and connector ( Connector); SMT specifies the FDDI station configuration, ring configuration, and ring control features, including station insertion and deletion, startup, fault separation and recovery, mode arrangement, and statistical collection.


Application Environment

FDDI can be mainly used in the following environments.

(1) The computer room network, also known as the back-end network, is used for the connection between large computers and high-speed peripherals in the computer room, as well as environments that require high reliability, transmission rate, and system fault tolerance.

(2) The backbone network of the office or building group, also known as the front-end network, is used to connect a large number of minicomputers, workstations, personal computers and various peripherals.

(3) The backbone network of the campus network or enterprise network is used to connect minicomputers, servers, workstations, personal computers and local area networks distributed in various buildings in the campus or enterprise.

(4) Multiple campus networks or corporate backbone networks are used to connect multiple campus networks and enterprise networks that are several kilometers away from each other, and become a regional backbone network that interconnects multiple campus networks and enterprise networks.


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