ccna中文課件16.廣域網(wǎng)技術(shù)

WAN連接了解WAN技術(shù)IntroducingWANsWhatisaWAN?IntroducingWANs(Cont.)WhyareWANsneeded?WANsvs.LANsWAN=AcollectionofLANsWANsvs.LANs(Cont.)

WANDevicesRoutersCSU/DSUWANswitchesCoreroutersModemsWANDevices(Cont.)

RoleofRoutersinWANsWANsvs.LANsSerialWANCabling

WANLayer2Protocols

WANLinkOptionsWANLinkOptions(Cont.)Point-to-PointConnectivityEthernetemulation:簡單價格適中靈活SerialCommunicationLinksSeriallinksuseleasedlinestoprovideadedicatedconnection.SerialCommunicationLinksThesearethetypicalWANspeedsfortheUnitedStates:T1(1.544Mb/s)T2=4T1lines(6Mb/s)T3=28T1lines(45Mb/s)T4=168T1lines(275Mb/s)ThesearethetypicalWANspeedsforEurope:E1(2Mb/s)E2=128E0lines(8Mb/s)E3=16E1lines(34Mb/s)E4=64E1lines(140Mb/s)HDLC和CiscoHDLCHDLCspecifiesanencapsulationmethodfordataonsynchronousserialdatalinks.RouterX(config-if)#encapsulationhdlc啟用CiscoHDLC封裝在同步串行接口上使用默認封裝配置HDLC封裝Point-to-PointProtocolOverviewofPPP:PPPprovidesastandardmethodfortransportingdatagramsoverpoint-to-pointlinks.PPPsupportsauthentication.Point-to-PointProtocol(Cont.)PPPisalayeredarchitecture:PPPcancarrypacketsfromseveralprotocolsuitesusingNCP.PPPcontrolsthesetupofseverallinkoptionsusingLCP.PPPConfigurationPPPconfigurationonRouterAPPPConfiguration(Cont.)PPPconfigurationonRouterBPPPConfiguration(Cont.)

PPPAuthentication:PAPPasswordAuthenticationProtocol:Passwordaresentinplaintext.Thepeerisincontrolofattempts.PPPAuthentication:CHAPChallengeHandshakeAuthenticationProtocol:Hashvalues,notactualpasswords,aresentacrossthelink.Thelocalrouterorexternalserverisincontrolofauthenticationattempts.ConfiguringCHAPforPPPAuthentication

配置PPP和身份驗證RouterX(config-if)#encapsulationppp啟用PPP封裝RouterX(config)#hostnamename給路由器指定主機名RouterX(config)#usernamenamepasswordpassword標識遠程路由器的用戶名和口令RouterX(config-if)#pppauthentication

{chap|chappap|papchap|pap}啟用PAP或CHAP身份驗證ConfiguringCHAPforPPPAuthentication(Cont.)ConfiguringCHAPauthenticationonRouterA.ConfiguringCHAPforPPPAuthentication(Cont.)ConfiguringCHAPauthenticationonRouterB.VerifyingCHAPConfigurationThedebugpppauthenticationcommandsshowsthesuccessfulCHAPoutputandverifiesPPPauthentication.總結(jié)PPP是適用于WAN的常用第2層協(xié)議。PPP包括兩個組件：協(xié)商連接的LCP和封裝流量的NCP?？蓪PP配置為使用PAP或CHAP。PAP以明文形式發(fā)送所有信息。CHAP使用MD5哈希。常用PPP驗證命令包括用于檢驗PPP封裝的showinterface

命令，以及用于檢驗LCP握手的debugpppnegotiation

命令。WAN有三大特點：連接分布于相距甚遠的不同地域的設(shè)備；使用運營