CCNA (640-802)教學(xué)培訓(xùn)課件：32-幀中繼建立WAN連接

幀中繼幀中繼概述使用虛電路建立的連接面向連接的服務(wù)幀中繼術(shù)語(yǔ)幀中繼默認(rèn)值：NBMA選擇幀中繼拓?fù)浣鉀QNBMA連通性問(wèn)題在NBMA環(huán)境中使用水平分割會(huì)出現(xiàn)問(wèn)題。解決方案：子接口單個(gè)物理接口模擬多個(gè)邏輯接口。LMI接收來(lái)自幀中繼交換機(jī)且在本地有效的DLCI。逆向ARP將本地DLCI映射到遠(yuǎn)程路由器網(wǎng)絡(luò)層地址。

幀中繼地址映射幀中繼信令Cisco支持三種LMI標(biāo)準(zhǔn)：CiscoANSIT1.617AnnexDITU-TQ.933AnnexA逆向ARP和LMI的操作過(guò)程逆向ARP和LMI的操作過(guò)程（續(xù)）配置基本幀中繼配置靜態(tài)幀中繼映射

在以下情況中配置靜態(tài)幀中繼映射：幀中繼對(duì)等點(diǎn)不支持逆向ARP需要控制PVC上的廣播流量需要在PVC上擁有不同的幀中繼封裝配置幀中繼子接口點(diǎn)對(duì)點(diǎn)此類子接口的作用相當(dāng)于租用線路。每個(gè)點(diǎn)對(duì)點(diǎn)子接口需要擁有自己的子網(wǎng)。點(diǎn)對(duì)點(diǎn)子接口適用于集中星型拓?fù)?。多點(diǎn)此類子接口的作用相當(dāng)于NBMA網(wǎng)絡(luò)，因此它們不解決水平分割問(wèn)題。多點(diǎn)子接口可節(jié)省地址空間，因?yàn)樗褂脝我蛔泳W(wǎng)。多點(diǎn)子接口適用于偏網(wǎng)狀拓?fù)浜腿W(wǎng)狀拓?fù)?。配置幀中繼點(diǎn)對(duì)點(diǎn)子接口配置幀中繼多點(diǎn)子接口RouterX#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,outputhangneverLastclearingof"showinterface"countersneverQueueingstrategy:fifoOutputqueue0/40,0drops;inputqueue0/75,0drops<省略部分輸出>檢驗(yàn)幀中繼運(yùn)行RouterX#showinterfacestypenumber顯示有關(guān)幀中繼DLCI和LMI的信息RouterX#showframe-relaylmi

LMIStatisticsforinterfaceSerial0(FrameRelayDTE)LMITYPE=CISCOInvalidUnnumberedinfo0InvalidProtDisc0InvaliddummyCallRef0InvalidMsgType0InvalidStatusMessage0InvalidLockShift0InvalidInformationID0InvalidReportIELen0InvalidReportRequest0InvalidKeepIELen0NumStatusEnq.Sent113100NumStatusmsgsRcvd113100NumUpdateStatusRcvd0NumStatusTimeouts0檢驗(yàn)幀中繼運(yùn)行（續(xù)）RouterX#showframe-relaylmi[typenumber]顯示LMI統(tǒng)計(jì)信息顯示LMI調(diào)試信息檢驗(yàn)幀中繼運(yùn)行（續(xù)）RouterX#debugframe-relaylmiFrameRelayLMIdebuggingisonDisplayingallFrameRelayLMIdataRouterX#1w2d:Serial0(out):StEnq,myseq140,yourseen139,DTEup1w2d:datagramstart=0xE008EC,datagramsize=131w2d:FRencap=0xFCF103091w2d:007501010103028C8B1w2d:1w2d:Serial0(in):Status,myseq1401w2d:RTIE1,length1,type11w2d:KAIE3,length2,yourseq140,myseq1401w2d:Serial0(out):StEnq,myseq141,yourseen140,DTEup1w2d:datagramstart=0xE008EC,datagramsize=131w2d:FRencap=0xFCF103091w2d:007501010103028D8C1w2d:1w2d:Serial0(in):Status,myseq1421w2d:RTIE1,length1,type01w2d:KAIE3,length2,yourseq142,myseq1421w2d:PVCIE0x7,length0x6,dlci100,status0x2,bw0檢驗(yàn)幀中繼運(yùn)行（續(xù)）RouterX#showframe-relaypvc[typenumber[dlci]]顯示PVC統(tǒng)計(jì)信息RouterX#showframe-relaypvc100PVCStatisticsforinterfaceSerial0(FrameRelayDTE)DLCI=100,DLCIUSAGE=LOCAL,PVCSTATUS=ACTIVE,INTERFACE=Serial0

inputpkts28outputpkts10inbytes8398

outbytes1198droppedpkts0inFECNpkts0

inBECNpkts0outFECNpkts0outBECNpkts0

inDEpkts0outDEpkts0

outbcastpkts10outbcastbytes1198

pvccreatetime00:03:46,lasttimepvcstatuschanged00:03:47檢驗(yàn)幀中繼運(yùn)行（續(xù)）RouterX#clearframe-relay-inarpRouterX#showframe-relaymap動(dòng)態(tài)清除使用逆向ARP動(dòng)態(tài)創(chuàng)建的幀中繼映射顯示當(dāng)前的幀中繼映射條目RouterX#showframe-relaymapSerial0(up):ip10.140.1.1dlci100(0x64,0x1840),dynamic,broadcast,,statusdefined,activeRouterX#clearframe-relay-inarpRouterX#showframemapRouterX#總結(jié)幀中繼PVC由DLCI標(biāo)識(shí)，PVC的