广域网接入技术

广域网接入技术WAN概述WAN第二层封装帧中继概述配置帧中继配置帧中继子接口ISDN概述ISDN部件按需拨号路由选择概述配置标准DDR1/12/20231广域网接入技术WANsconnectremotesites.Connectionrequirementsvarydependingonuserrequirements,cost,andavailability.1/12/20232广域网接入技术-WAN连接方式1/12/20233广域网接入技术-WAN术语CPE：用户室内设备Demarcation:分界点Localloop：本地回路COSwitch：中心局交换机Tollnetwork：长途网络1/12/20234典型广域网链路层协议配置合适的数据链路层封装类型选择哪种协议取决于WAN技术和通信设备1/12/20235典型广域网链路层协议-HDLCUsesaproprietarydatafieldtosupportmultiprotocol

environmentsSupportsonlysingle-protocolenvironmentsHDLC常被用作路由器之间的点到点租用线的封装方法Cisco提供了一种专用的HDLC版本，同步串行链路的默认封装方法。CiscoHDLC帧包含一个专用的类型字段，起到协议字段的作用，使得多种网络层协议共享一条串行链路。1/12/20236典型广域网链路层协议-PPPPPP使用网络控制协议（NCP）子层来封装多种协议PPP使用链路控制协议（LCP）子层来协商和设置WAN数据链路的控制选项1/12/20237典型广域网链路层协议-PPP分层模型1/12/20238典型广域网链路层协议-PPPLCP配置选项1/12/20239典型广域网链路层协议-PPP会话建立PPP支持两种身份认证协议：PAP、CHAP1/12/202310典型广域网链路层协议-PPP认证PAP利用双向握手确认呼叫方的合法性当PPP链路建立阶段完成后，呼叫方重复发送用户名/口令对，直到认证被确认或未通过认证而拆除链路口令以明文的形式在链路上传送1/12/202311典型广域网链路层协议-PPP认证CHAP使用三次握手的方法周期性地验证Hash值(MD5)1/12/202312典型广域网链路层协议-PPP封装和认证例Router(config-if)#encapsulationpppEnablesPPPencapsulationRouter(config)#hostnamenameAssignsahostnametoyourrouterRouter(config)#usernamenamepasswordpasswordIdentifiestheusernameandpasswordofremoterouterRouter(config-if)#pppauthentication

{chap|chappap|papchap|pap}EnablesPAPand/orCHAPauthentication1/12/202313典型广域网链路层协议-PPP认证例演示1/12/202314帧中继概述面向连接虚电路帧中继网络本身不对用户数据进行错误检测CSU/DSU接收数字信号，并将信号编码为交换机可理解的数字信号类型帧中继运行在OSI的下二层OSIReferenceModelFrameRelayPhysicalPresentationSessionTransportNetworkData-LinkApplicationEIA/TIA-232,EIA/TIA-449,V.35,X.21,EIA/TIA-530FrameRelayIP/IPX/AppleTalk,etc.1/12/202316帧中继术语本地接入速率虚电路（VC）PVCSVC数据链路连接符（DLCI）

承诺信息速率（CIR）反向地址解析协议（反向ARP）

本地管理接口（LMI）前向显式拥塞通知（FECN）

后向显式拥塞通知（BECN）帧中继（NBMA）-问题

Problem:只有建立虚电路的两点间才能通信水平分割问题解决水平分割问题SplithorizoncancauseproblemsinNBMAenvironments.Subinterfacescanresolvesplithorizonissues.Solution:Asinglephysicalinterfacesimulatesmultiplelogicalinterfaces.UseLMItogetlocallysignificantDLCIfromtheFrameRelayswitch.UseInverseARPtomapthelocalDLCItotheremoterouter’snetworklayeraddress.帧中继连接的地址映射和LMI信令-地址映射CiscosupportsthreeLMIstandards:Cisco:ansi:ANSI标准

T1.617附录D定义的LMI类型Q933a:ITU-TQ.933附录A定义的LMI类型帧中继连接的地址映射和LMI信令-帧中继信令路由器收到LMI信息后,将把其VC状态更新到下列三种状态之一:活动状态非活动状态删除状态帧中继连接的地址映射和LMI信令-链路初始化帧中继连接的地址映射和LMI信令-链路初始化配置帧中继配置静态帧中继映射配置帧中继子接口-点到点配置帧中继子接口-多点Displaysline,protocol,DLCI,andLMIinformationRouter#showinterfacess0Serial0isup,lineprotocolisupHardwareisHD64570Internetaddressis/24MTU1500bytes,BW1544Kbit,DLY20000usec,rely255/255,load1/255EncapsulationFRAME-RELAY,loopbacknotset,keepaliveset(10sec)LMIenqsent19,LMIstatrecvd20,LMIupdrecvd0,DTELMIupLMIenqrecvd0,LMIstatsent0,LMIupdsent0LMIDLCI1023LMItypeisCISCOframerelayDTEFRSVCdisabled,LAPFstatedownBroadcastqueue0/64,broadcastssent/dropped8/0,interfacebroadcasts5Lastinput00:00:02,output00:00:02,outputhangneverLastclearingof"showinterface"countersneverQueueingstrategy:fifoOutputqueue0/40,0drops;inputqueue0/75,0drops<Outputomitted>查看帧中继连接的状态和信息Router#showframe-relaylmi

LMIStatisticsforinterfaceSerial0(FrameRelayDTE)LMITYPE=CISCOInvalidUnnumberedinfo0InvalidProtDisc0InvaliddummyCallRef0InvalidMsgType0InvalidStatusMessage0InvalidLockShift0InvalidInformationID0InvalidReportIELen0InvalidReportRequest0InvalidKeepIELen0NumStatusEnq.Sent113100NumStatusmsgsRcvd113100NumUpdateStatusRcvd0NumStatusTimeouts0查看有关LMI数据流的统计信息Router#showframe-relaypvc100PVCStatisticsforinterfaceSerial0(FrameRelayDTE)DLCI=100,DLCIUSAGE=LOCAL,PVCSTATUS=ACTIVE,INTERFACE=Serial0inputpkts28outputpkts10inbytes8398outbytes1198droppedpkts0inFECNpkts0inBECNpkts0outFECNpkts0outBECNpkts0inDEpkts0outDEpkts0outbcastpkts10outbcastbytes1198pvccreatetime00:03:46,lasttimepvcstatuschanged00:03:47查看帧中继连接和关于数据流的统计信息Displaystheroutemaps,eitherstaticordynamicRouter#showframe-relaymapSerial0(up):ipdlci100(0x64,0x1840),dynamic,broadcast,,statusdefined,active查看帧中继映射条目ClearsdynamicallycreatedFrameRelaymapsRouter#showframe-relaymapSerial0(up):ipdlci100(0x64,0x1840),dynamic,broadcast,,statusdefined,activeRouter#clearframe-relay-inarpRouter#showframemapRouter#清除动态创建的帧中继映射1/12/202332什么是ISDN？Voice,data,video,andspecialservicesISDN部件1/12/202334BRI呼叫建立过程1/12/202335功能是设备或硬件参考点是分界点或接口ISDNCPE和参考点1/12/202336ISDNBRI接口1/12/202337ISDNPRI接口1/12/202338ISDN交换机类型和服务配置文件标识符（SPID）Manyprovidersusemanydifferentswitchtypes.Servicesvarybyregionandcountry.1/12/202339Router(config)#isdnswitch-typeswitch-typeThecommandspecifiesthetypeofISDNswitchwithwhichtheroutercommunicates.Otherconfigurationrequirementsvaryforspecificproviders.Step1:SpecifytheISDNswitchtype.Router(config-if)#isdnswitch-typeswitch-type配置ISDNBRI1/12/202340SetsaBchannelSPIDrequiredbymanyserviceprovidersStep2:(Optional)SettingSPIDsSetsaSPIDforthesecondBchannelRouter(config-if)#isdnspid1spid-number[ldn]Router(config-if)#isdnspid2spid-number[ldn]配置ISDNBRI（续）1/12/202341配置ISDNPRIRouter(config)#isdnswitch-typeswitch-typeRouter(config)#controllercontrollerslot/portRouter(config-controller)#pri-grouptimeslotsrangeStep1:指定D信道的交换机类型Step2:配置控制器时钟脉冲源、帧类型和线路编码特征Step3:指定PRI使用T1/E1的哪些信道/时隙1/12/202342ISDNPRIExamplesRouter(config)#controllerT13/0Router(config-controller)#framingesfRouter(config-controller)#linecodeb8zsRouter(config-controller)#pri-grouptimeslots1-24

Router(config-controller)#interfaceSerial3/0:23Router(config-if)#isdnswitch-typeprimary-5essRouter(config-if)#nocdpenableT1SampleConfigurationRouter(config)#controllerE13/0Router(config-controller)#framingcrc4Router(config-controller)#linecodehdb3Router(config-controller)#pri-grouptimeslots1-31

Router(config-controller)#interfaceSerial3/0:15Router(config-if)#isdnswitch-typeprimary-net5Router(config-if)#nocdpenableE1SampleConfiguration1/12/202343ConnectswhenneededDisconnectswhenfinishedISDNorPSTN按需拨号路由选择1/12/202344Periodic（间歇性）connectionsSmallamountsofdata何时用DDR？1/12/2023451.Routetodestinationisdetermined.2.InterestingpacketsdictateDDRcall.3.Dialerinformationislookedup.4.Trafficistransmitted.5.Callisterminated.DDR工作原理1/12/202346312Definestaticroutes—WhatroutedoIuse?

Specifyinterestingtraffic—Whattrafficenablesthelink?Configurethedialerinformation—WhatnumberdoIcall?配置标准DDR11/12/202347配置静态路由1/12/202348dialer-list1protocolippermitdialer-list1protocoliplist101access-list101denytcpanyanyeqftpaccess-list101denytcpanyanyeqtelnetaccess-list101permitipanyanyAnyIPtrafficwillinitiatethelinkwithoutaccesslists.AnyIPtraffic,exceptFTPandTelnet,willinitiatethelinking.Usingaccesslistsgivesfinercontrol.DeniesFTPDeniesTelnet指定感兴趣的数据流1/12/202349Appliesrulesdefinedbydialer-listtoindividualinterfaceshostnameHome!isdnswitch-typebasic-5ess!usernamecentralpasswordciscointerfaceBRI0ipaddressencapsulationpppdialeridle-timeout180dialermapipnameCentral5552000dialer-group1nofair-queuepppauthenticationchap!routerripnetwork!noipclasslessiprouteiproute!dialer-list1protocolippermitBothValues

MustMatch配置拨号信息1/12/202350配置拨号信息（续）1/12/202351EstablishestheamountoftrafficonthelinkbeforeasecondlinkisenabledRouter(config-if)#dialeridle-timeoutsecondsRouter(config-if)#dialerload-thresholdload

[outbound|inbound|either]Establishestheidletimebeforedisconnect定义负载均衡（可选）和计时器1/12/202352132hostnameHome!isdnswitch-typebasic-5ess!usernamecentralpasswordciscointerfaceBRI0ipaddressencapsulationpppdialeridle-timeout180dialermapipnameCentral5552000dialer-group1nofair-queuepppauthenticationchap!routerripnetwork!noipclasslessiprouteiproutedialer-list1protocolippermit!配置总结1/12/202353配置ISDNPRI和拨号配置文件1/12/202354拨号接口、物理接口和拨号池间的关系1/12/202355拨号配置1/12/202356interfacedialer1ipaddressencapsulationpppdialerremote-nameSmalluserdialerstring5554540dialeridle-timer180dialerpool1dialer-group1pppauthenticationchap!interfacedialer2ipaddressencapsulationpppdialerremote-nameMediumuserdialerstring5551234dialeridle-timer180dialerpool1dialer-group2(cont.)interfacedialer3ipaddressencapsulationpppdialerremote-namePoweruserdialerstring4155554321dialeridle-timer300dialerpool1dialer-group3配置拨号接口1/12/202357配置物理接口1/12/202358Router#pingortelnetRouter#showdialerRouter#showisdnactiveRouter#showisdnstatusTriggersalinkDisplayscurrentstatusofthelinkDisplayscallstatuswhilecallisinprogressDisplaysthestatusofanISDNconnectionRouter#showiprouteDisplaysallroutes,includingstaticroutes验证DDR和ISDN1/12/202359NASX#showdialerinterfacebri0DialString Successes Failures Lastcalled Laststatus5553872 6 0 19secs Successful0incomingcall(s)havebeenscreened.BRI0:B-Channel1Idletimer(120secs),Fastidletimer(20secs)Waitforcarrier(30secs),Re-enable(15secs)Timeuntildisconnect102secsCurrentcallconnected00:00:19Connectedto5553872(system1)BRI0:B-Channel2Idletimer(120secs),Fastidletimer(20secs)Waitforcarrier(30secs),Re-enable(15secs)DialerstateisidleBRI0-dialertype=ISDNInterfaceboundtoprofileDialer0DialerstateisdatalinklayerupDialreason:ip(s=,d=)验证DDR和ISDN1/12/202360Router#debugdialer[events|packets]DisplaysDDRdebugginginformationaboutthepacketsreceivedonadialerinterfaceClearscurrentlyestablishedconnectionsfromtheinterfaceRouter#debugisdnq921ShowsISDNLayer2messagesRouter(config-if)#shutdownShowsISDNcallsetupandteardownactivityRouter#debugisdnq931诊断DDR和ISDN1/12/202361Router#debugisdnq921

Jan314:52:24.475:ISDNBR0:TX->INFOcsapi=0tei=64ns=5nr=2i=0x08010705040288901801837006803631383835Jan314:52:24.503:ISDNBR0:RX<-RRrsapi=0tei=64nr=6Jan314:52:24.527:ISDNBR0:RX<-INFOcsapi=0tei=64ns=2nr=6i=0x08018702180189Jan314:52:24.535:ISDNBR0:TX->RRrsapi=0tei=64nr=3Jan314:52:24.643:ISDNBR0:RX<-INFOcsapi=0tei=64ns=3nr=6i=0x08018707Jan314:52:24.655:ISDNBR0:TX->RRrsapi=0tei=64nr=4%LINK-3-UPDOWN:InterfaceBRI0:1,changedstatetoupJan314:52:24.683:ISDNBR0:TX->INFOcsapi=0tei=64ns=6nr=4i=0x0801070FJan314:52:24.699:ISDNBR0:RX<-RRrsapi=0tei=64nr=7%LINEPROTO-5-UPDOWN:LineprotocolonInterfaceBRI0:1,changedstatetoup%ISDN-6-CONNECT:InterfaceBRI0:1isnowconnectedto61885goodieJan314:52:34.415:ISDNBR0:RX<-RRpsapi=0tei=64nr=7Jan314:52:34.419:ISDNBR0:TX->RRfsapi=