思科网络技术学院教程(第三章物理层和数据链路层)

第三章copyright?1998,ciscosystems,inc.icrc_revision_11.3物理层和数据链路层

物理层和数据链路层标准physical(bits,signals,clocking)lanwandatalink(frames)ethernet802.3802.5fddi802.2llcx.25linkframerelayisdnppp

eia-530

v.35

dialondemandsdlchdlcv.24hssig.703

eia/tia-232eia/tia-449局域网数据链路子层llc完成上半层的软件功能mac完成下半层的硬件功能mediaaccesscontrol（介质访问控制）logicallinkcontrol（逻辑链路控制）networkdatalinkphysicalllcmacmacframe802.3llcpacketordatagram物理层和逻辑地址0000.0c12.3456mac地址mac地址被烧进网络接口卡的rom芯片中24bits24bits0000.0c12.3456制造商代码序列号romrammac地址判定hostyhostzqueryresponseexample1:destinationlocalrouteraexample2:destinationnotlocalhostzbroadcasthostzmac?hostzhostymachostzmachostyquerybroadcasthostzmac?hostzresponsehostymacrouteramacroutingtable:netforhostz练习:

mac地址判定hosta0000.0c12.1111hostb0000.0c12.2222hostd0000.0c12.4444routerc0000.0c12.3333routerc0000.0c12.5555networkynetworkx局域网技术

copyright?1998,ciscosystems,inc.icrc_revision_11.3ethernettokenringfddilan技术概览fddidualringethernet和ieee802.3ethernet是一种共享介质的技术，它允许多台设备同时连接、交替使用同一传输介质。ethernet/802.3的物理层host10baset——双绞线10base2——以太网细缆

10base5——以太网粗缆pcmacsunhosthubmacethernet/802.3接口cisco路由器的ethernet/802.3的接口名字使用字母e加一个数字(例如：

e0)0800.2006.1a560000.0c12.7c4de0e10800.890c.34d50000.0c12.83e2ethernet/802.3工作原理abcdethernet/802.3工作原理abcdethernet/802.3工作原理abcddapplicationpresentationsessiontransportnetworkdatalinkphysicalethernet/802.3工作原理abcddbandcapplicationpresentationsessiontransportnetworkdatalinkphysicalapplicationpresentationsessiontransportnetworkdatalinkphysicalethernet/802.3广播dcbaapplicationpresentationsessiontransportnetworkdatalinkphysicalapplicationpresentationsessiontransportnetworkdatalinkphysicalapplicationpresentationsessiontransportnetworkdatalinkphysicalapplicationpresentationsessiontransportnetworkdatalinkphysicalabcdethernet/802.3的冲突检测ethernet/802.3的冲突检测abcdethernet/802.3的冲突检测cdcollisionabethernet/802.3的冲突检测collisionabcdcdabethernet/802.3的冲突检测abcdcollisionabcdjamjamjamjamjamjamethernet/802.3的冲突检测abcdcollisionabcdjamjamjamjamjamjam广域网技术

copyright?1998,ciscosystems,inc.icrc_revision_11.3wan技术概览sdlchdlclapbpppx.25framerelayisdnwan的物理层协议(modem)dataterminalequipment（与数据通信网相连的用户设备）dtedatacircuit-terminatingequipment（数据通信网末端设备）csu——信道服务单元dsu——数据服务单元dceeia/tia-232v.35x.21hssiotherscsu/dsuwan接口电缆datalinklayer:wanprotocolssdlc——synchronousdatalinkcontrolhdlc——high-leveldatalinkcontrollapb——linkaccessprocedure,balancedframerelay——simplifiedversionof