广域网接入技术1

2020/2/51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DDR2020/2/52广域网接入技术WANsconnectremotesites.Connectionrequirementsvarydependingonuserrequirements,cost,andavailability.2020/2/53广域网接入技术-WAN连接方式2020/2/54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2020/2/55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2020/2/56典型广域网链路层协议-HDLCUsesaproprietarydatafieldtosupportmultiprotocolenvironmentsSupportsonlysingle-protocolenvironmentsHDLC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。2020/2/57典型广域网链路层协议-PPPPPP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2020/2/58典型广域网链路层协议-PPP分层模型2020/2/59典型广域网链路层协议-PPPLCP配置选项2020/2/510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、CHAP2020/2/511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2020/2/512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)2020/2/513典型广域网链路层协议-PPP封装和认证例Router(config-if)#encapsulationpppEnablesPPPencapsulationRouter(config)#hostnamenameAssignsahostnametoyourrouterRouter(config)#usernamenamepasswordpasswordIdentifiestheusernameandpasswordofremoterouterRouter(config-if)#pppauthentication{chap|chappap|papchap|pap}EnablesPAPand/orCHAPauthentication2020/2/514典型广域网链路层协议-PPP认证例演示帧中继概述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2020/2/516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.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,lineprotocolisupHardwareisHD64570Internetaddressis10.140.1.2/24MTU1500bytes,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,outputhangneverLastclearingofshowinterfacecountersneverQueueingstrategy:fifoOutputqueue0/40,0drops;inputqueue0/75,0dropsOutputomitted查看帧中继连接的状态和信息Router#showframe-relaylmiLMIStatisticsforinterfaceSerial0(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):ip10.140.1.1dlci100(0x64,0x1840),dynamic,broadcast,,statusdefined,active查看帧中继映射条目2020/2/532ClearsdynamicallycreatedFrameRelaymapsRouter#showframe-relaymapSerial0(up):ip10.140.1.1dlci100(0x64,0x1840),dynamic,broadcast,,statusdefined,activeRouter#clearframe-relay-inarpRouter#showframemapRouter#清除动态创建的帧中继映射什么是ISDN？Voice,data,video,andspecialservices2020/2/534ISDN部件2020/2/535BRI呼叫建立过程2020/2/536功能是设备或硬件参考点是分界点或接口ISDNCPE和参考点2020/2/537ISDNBRI接口2020/2/538ISDNPRI接口2020/2/539ISDN交换机类型和服务配置文件标识符（SPID）Manyprovidersusemanydifferentswitchtypes.Servicesvarybyregionandcountry.2020/2/540Router(config)#isdnswitch-typeswitch-typeThecommandspecifiesthetypeofISDNswitchwithwhichtheroutercommunicates.Otherconfigurationrequirementsvaryforspecificproviders.Step1:SpecifytheISDNswitchtype.Router(config-if)#isdnswitch-typeswitch-type配置ISDNBRI2020/2/541SetsaBchannelSPIDrequiredbymanyserviceprovidersStep2:(Optional)SettingSPIDsSetsaSPIDforthesecondBchannelRouter(config-if)#isdnspid1spid-number[ldn]Router(config-if)#isdnspid2spid-number[ldn]配置ISDNBRI（续）2020/2/542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