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LAN-Standards

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					                     Ethernet
• The Most Popular LAN Technology
   – Carries perhaps 80% of all LAN traffic
• Created at the Xerox Palo Alto Research Center
  (PARC)
• Initially standardized by Digital Equipment
  Corporation, Intel, and Xerox
   – Ethernet Version 2 (Ethernet II) was the final standard
     of this partnership
   – Still used on some LANs
            LAN Standards
• Now, most LAN Standards are Developed
  by the IEEE
  – Institute for Electrical and Electronics
    Engineers
  – Not just Ethernet LAN standards
            LAN Standards
• Now, most LAN Standards are Developed
  by the IEEE
  – Developed through the IEEE’s 802 LAN MAN
    Standards Committee
     • MAN is a metropolitan area network (for a city and
       its suburbs)
  – IEEE LAN standards are submitted to ISO for
    ratification as OSI standards
             LAN Standards
• 802 Committee has Working Groups
  – Working groups develop individual standards
  – Submit to whole 802 committee
  – 802.1 develops priority standards and other general
    standards
  – 802.3 has taken over the development of new Ethernet
    standards
  – 802.5 develops Token-Ring Network standards
  – 802.11 develops wireless LAN standards
    LANs are Subnet Standards
• Only Physical and Data Link Layer
  standards
• Of course, clients and servers must be
  compatible at other layers as well
         Application         Application
          Transport          Transport
           Internet           Internet
         LAN Subnet         LAN Subnet
           (NIC)              (NIC)
   LANs are Subnet Standards
• Implemented by the NICs
  – NICs on the two machines must talk to one another
• Hubs and Switches Merely Relay Transmissions
  – Hubs implement Physical layer only (no Data Link
    layer needed)
  – Switches implement the Physical and Data Link layers
• Wiring Implements Physical Layer

				
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posted:11/23/2011
language:English
pages:6