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Lecture #15: High speed LANs

Lecture #15: High speed LANs. C o n t e n t s . Fast LANs FDDI Fast Ethernet HIPPI. 2. 3. 7. 8. Fast LANs. ATM. ATM. ETHERNET. . . ETHERNET. B. B. Inter LAN backbone e.g. FDDI Ring. B. B. B. B. B. B. TOKEN RING. TOKEN RING. FDDI. FDDI. FIBER CHANNEL. Bridge. B.

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Lecture #15: High speed LANs

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  1. Lecture #15: High speed LANs C o n t e n t s • Fast LANs • FDDI • Fast Ethernet • HIPPI 2 3 7 8

  2. Fast LANs ATM ATM ETHERNET ... ... ETHERNET B B Inter LAN backbone e.g. FDDI Ring B B B B B B TOKEN RING TOKEN RING FDDI FDDI FIBER CHANNEL Bridge B FIBER CHANNEL Advances in transmission speed and distance. Technology FDDI Fast Ethernet Application inter-LAN backbones when 100 Mb/S and upper bandwidth is needed

  3. FDDI • FDDI (Fiber Distributed Data Interface) • token ring topology (because of the media) • standard bandwidth 100 Mb/S • ring length up to 200 km • application • inter LAN backbones • PCM trunks and ISDN traffic (FDDI-II) • FDDI physical implementation • multimode fibers (thicker, based on the internal reflection, slower but cheaper than thin single-mode fibers) • LED as light sources • BER under 10-10 (Bit Error Rate).

  4. FDDI • Topology: • doubled ring for full duplex transmission or • single ring with token circulation • FDDI Station classes - A/B • 4-out-of-5 bit coding • - each { }is coded with 5 bits – 75% more congested coding than Manchester code but not self-clocked  synchronization by leading preamble for each frame. 4-bit data sequence (16) frame delimiters (3) control sequences (2) hardware signals (3)

  5. FDDI Token Ring and Frame • Much longer circumnavigate distances than in 802.5 allow multiple frame circulation in the ring • One-token-multiple-frames scheme (asynchronous “bursty” traffic) • General Frame format • preamble • Start/End Delimiters (SD/ED) • Frame Control byte (FC) /Data/control frame/ • Destination and Source Addresses - 2 or 6 bytes (DA, SA) • unlimited Info • FCS - CRC error control • Frame Status byte (FS) • Token Frame format • preamble • Frame Control byte (FC) • Frame Status byte (FS) 15/1 15/2

  6. FDDI Token Ring Timing and Synchronous Transmission • FDDI token ring timing: • Token holding timer - station time limit for token holding • Token rotation timer - starting the token recovery procedure after the time-out • Valid transmission timer - detecting transient ring problems after the time-out • Synchronous transmission over FDDI (“stream traffic”): • synchronous frame • header field (16B) for non-circuit-switching data • data field (up to 96B) - 4 T1 (4x24) PCM channels of 1.544Mb/S or 3 E1 (3x32) CCITT channels of 2.048 Mb/S. • timing - up to 16 sync. frames per 125mS period i.e. up to 8000*16 sync. frames/S (synchronous transmission bandwidth 8000*16*96B*8b=98.304 b/S)

  7. Fast ETHERNET • Faster Ethernet MAC protocol over 10 times shorter transmission cable • ETH cable segments are connected by hubs • Cabling • cat. 3 twisted pair - 4 twisted pairs: to/from hub + 2 pairs switchable to the active station • cat. 5 twisted pair - 2 twisted pairs: to/from hub • fiber - in and out multimode fiber up to 2 km • Twisted pair hubs • shared hub • switched (buffered) hub 4/47

  8. HIPPI Standard pb bFF bFE . . . b1 b0 p31 31 31 31 31 p30 30 30 30 30 . . . . . . . . . . . . . . . p1 1 1 1 1 p0 0 0 0 0 • HIPPI (High Performance Parallel Interface) • Point-to-Point parallel computer interface with Primary/Secondary logical connectivity • crossbar switch extension • cabling: 50 twisted pair lines in parallel splitting 32b/18b (data/interface control incl. 1 parity bit) simplex mode; two lines in parallel for full duplex mode; maximum line length 25m. • Frame format: 256 words (32b) with parity bit per each word and and a parity word at the end of each frame (no CRC): 4/48

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