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FIBER DISTRIBUTED DATA INTERFACE (FDDI)

FIBER DISTRIBUTED DATA INTERFACE (FDDI). Introduction. Shared media network like Ethernet ( IEEE 802.3) & IBM token ring (IEEE 802.5) 100 mbps speed Runs on optical fiber American National Standards Institute (ANSI) standard. FDDI Basic Principle. Token ring network like IEEE 802.5

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FIBER DISTRIBUTED DATA INTERFACE (FDDI)

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  1. FIBER DISTRIBUTED DATA INTERFACE (FDDI)

  2. Introduction • Shared media network like Ethernet ( IEEE 802.3) & IBM token ring (IEEE 802.5) • 100 mbps speed • Runs on optical fiber • American National Standards Institute (ANSI) standard

  3. FDDI Basic Principle • Token ring network like IEEE 802.5 • Token: a special sequence of bits • Token circulates around the ring • A station removes the token from ring before transmission • After transmission, the station returns the token to the ring • Collisions are prevented as there is only one token in the ring

  4. TOKEN RING NETWORK

  5. FDDI Basic Principle • Token ring network like IEEE 802.5 • Token: a special sequence of bits • Token circulates around the ring • A station removes the token from ring before transmission • After transmission, the station returns the token to the ring • Collisions are prevented as there is only one token in the ring

  6. FDDI Physical Properties • Dual-counter-rotating token ring architecture • One ring is primary and the other secondary • Up to 500 stations with a maximum distance of 2 km between any pair of stations for multimode fiber • With single-mode fiber the distance can be up to 40 km • Maximum ring length is 100 km (total fiber length is 200 km for two rings) • Uses 4b/5b encoding

  7. FDDI Dual Ring Architecture

  8. Operation On Failure Of The Primary Ring

  9. FDDI Architectural Model • According to the OSI-RM, FDDI specifies layer 1 (physical layer) and part of layer 2 (data link control layer) • The physical layer handles the transmission of raw bits over a communications link • The data link control (dlc) layer is responsible for maintaining the integrity of information exchanged between two points

  10. Relationship Between FDDI and OSI-RM

  11. The PMD Layer • PMD layer defines the type of media interconnection and its characteristics such as transmitter power, frequencies, receiver sensitivities, bit error rates (per), optical components etc. • PMD-MMF: MultiMode (62.5 micron core diameter) Fiber • PMD-SMF: Single-Mode (8-10 micron core diameter) Fiber • Also defines STP, UTP as media and FDDI on SONET

  12. The PHY layer • Provides the media independent functions associated with the OSI physical layer • Reception: decodes the received bit stream from PMD into a symbol stream for use by the mac layer • Transmission: encodes the data and control symbols provided by mac using 4b/5b encoding for the PMD layer • Also provides SMT the services required for the establishment and maintenance of the FDDI ring (by continuously listening to the incoming signal)

  13. The MAC Layer • Provides fair & deterministic access • Fair: no node has advantage over another in accessing the medium • Deterministic: under error-free conditions, the time a node has to wait to access the medium can be predicted • Medium access is controlled by a token • Token permits the node that receives it to transmit frames • The mac layer of the node that generated the frame is responsible for removing the token

  14. The SMT Layer • A sophisticated, built-in network monitoring and management capability • SMT is not an OSI-RM specification • Making use of the services provided by PMD, PHY, and MAC, it carries out many functions such as node initialization, bypassing faulty nodes, coordination of node insertion and removal, fault isolation and recovery • SMT is most commonly implemented as a software process running on the FDDI device

  15. FDDI Benefits • High bandwidth (10 times more than Ethernet) • Larger distances between FDDI nodes because of very low attenuation ( 0.3 dB/km) in fibers • Improved signal-to-noise ratio because of no interference from external radio frequencies and electromagnetic noise • Per typical of fiber-optic systems (10^-11) is substantially better than that in copper (10^-5) and microwave systems (10^-7) • Very difficult to tap signals form a fiber cable

  16. Comparison Of Transmission Media

  17. FDDI Limitations • High cost of optical components required for transmission/reception of signals (especially for single mode fiber networks) • More complex to implement than existing low speed LAN technologies such as IEEE 802.3 and IEEE 802.5

  18. Applications of FDDI • Office automation at the desktop • Backbones for factory automation • Backend data center applications • Campus LAN interconnection • Intercampus Backbones Or Metropolitan Area Networks (mans) • Interconnection of private branch exchanges (pbxs) • Workgroup and departmental LANs • Integrated transport for multimedia applications

  19. A FDDI Backbone Network Example

  20. Comparison With Other Networks

  21. The End ……. Thank You …….

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