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2Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3物理层和数据链路层标准Physical(bits,signals,clocking)LANWANDataLink(frames)Ethernet802.3802.5FDDI802.2LLCX.25LinkFrameRelayISDNPPPEIA-530V.35DialonDemandSDLCHDLCV.24HSSIG.703EIA/TIA-232EIA/TIA-4493Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3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）NetworkDataLinkPhysicalLLCMACMACFrame802.3LLCPacketorDatagram4Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3物理层和逻辑地址0000.0c12.34565Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3MAC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ROMRAM6Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3MAC地址判定HostYHostZQueryResponseExample1:DestinationlocalRouterAExample2:DestinationnotlocalHostZBroadcastHostZMAC?HostZHostYMACHostZMACHostYQueryBroadcastHostZMAC?HostZResponseHostYMACRouterAMACRoutingTable:NetforHostZ7Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3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_11.39Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3TokenRingEthernetTokenRingFDDILAN技术概览FDDIDualRing10Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3Ethernet和IEEE802.3•Ethernet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。11Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3Ethernet/802.3的物理层Host10BaseT——双绞线10Base2——以太网细缆10Base5——以太网粗缆PCMacSunHostHubMAC12Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3Ethernet/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.34d50000.0c12.83e213Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3Ethernet/802.3工作原理ABCD14Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3Ethernet/802.3工作原理ABCD15Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3Ethernet/802.3工作原理ABCDDApplicationPresentationSessionTransportNetworkDataLinkPhysical16Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3Ethernet/802.3工作原理ABCDDBandCApplicationPresentationSessionTransportNetworkDataLinkPhysicalApplicationPresentationSessionTransportNetworkDataLinkPhysical17Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3Ethernet/802.3广播DCBAApplicationPresentationSessionTransportNetworkDataLinkPhysicalApplicationPresentationSessionTransportNetworkDataLinkPhysicalApplicationPresentationSessionTransportNetworkDataLinkPhysicalApplicationPresentationSessionTransportNetworkDataLinkPhysical18Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3ABCDEthernet/802.3的冲突检测19Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3Ethernet/802.3的冲突检测ABCD20Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3Ethernet/802.3的冲突检测CDCollisionAB21Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3Ethernet/802.3的冲突检测CollisionABCDCDAB22Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3Ethernet/802.3的冲突检测ABCDCollisionABCDJAMJAMJAMJAMJAMJAM23Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3Ethernet/802.3的冲突检测ABCDCollisionABCDJAMJAMJAMJAMJAMJAM广域网技术Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.325Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3WAN技术概览SDLCHDLCLAPBPPPX.25FrameRelayISDN26Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3WAN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/DSU27Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3WAN接口电缆28Copyright?1998,CiscoSystems,Inc.ICRC_revision_11.3DataLinkLayer:WANProtocols•SDLC——SynchronousDataLinkControl•HDLC——High-LevelDataLinkControl•LAPB——LinkAccessProcedure,Balanced•FrameRelay——SimplifiedversionofHDLCframing•PPP——Point-to-PointProtocol•X.25——Packetlevelprotocol(PLP)•ISDN——IntegratedServicesDigitalNetwork(Modem)CSU/DSUCSU/DSU(Modem)