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 – 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 Transport Internet LAN Subnet (NIC) Application Transport Internet LAN Subnet (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