CCNA第16章帧中继.ppt

第十六章帧中继,通过本章的学习，您应该掌握以下内容：了解FrameRelay工作过程配置FrameRelay配置FrameRelay的子端口查看FrameRelay信息,本章目标,FrameRelay栈,OSI参考模型,FrameRelay,Physical,Presentation,Session,Transport,Network,DataLink,Application,EIA/TIA-232,EIA/TIA-449,V.35,X.21,EIA/TIA-530,FrameRelay,IP/IPX/AppleTalk,etc.,帧中继工作在数据链路层，依靠高层协议来进行错误检测和差错控制，支持多种高层协议。,FrameRelay术语,LocalAccessLoop=T1,LocalAccessLoop=64kbps,LocalAccessLoop=64kbps,DLCI:400,PVC,DLCI:500,LMI100=Active400=Active,DLCI:200,DLCI:100,PVC,FrameRelay术语,DCE(数据通信设备)DTE(数据终端设备)PVC:(永久虚电路)是一个逻辑概念，用于描述两端DTE设备之间的通信路径，类似于PPP连接中的专用物理链路，但是，一条物理链路上可以承载多条虚电路。DLCI（数据链路连接标识符）：用于标识在客户端设备CPE和本地帧中继交换机之间本地环路上建立的逻辑电路，帧中继交换机把两端DLCI标记的逻辑链路映射成一条PVC。DLCI是帧中继的本地地址，是局部概念,FrameRelay概述,使用虚电路进行连接提供面向对象的服务,DCEorFrameRelaySwitch,CSU/DSU,帧中继工作在用户端DTE设备和本地帧中继交换机之间，用于本地环路的通信控制；与帧中继交换机之间的数据传输无关。,FrameRelay概述,DCEorFrameRelaySwitch,CSU/DSU,DTE,帧中继是一种多路访问网络,在用户端DTE设备与本地帧中继交换机之间的一条物理链路上，可以建立多条PVC，提供一点对多点的面向连接的服务。,DTE,PVC1,PVC2,CSU/DSU,FrameRelay地址映射,从提供商那里得到本地的DLCI号建立目的地址和本地DLCI之间的映射关系(有InverseARP和Staticmapping两种方法）,DLCI:500,PVC,10.1.1.1,InverseARPorFrameRelaymap,IP(10.1.1.1),FrameRelay,DLCI(500),FrameRelay信号,LMI（本地管理接口）：是用户DTE设备和本地帧中继交换机的通信信令，用于管理DTE和本地帧中继交换机之间的通信，包括PVC状态消息和Keepalive消息等。,DLCI:400,PVC,Keepalive,CSU/DSU,DLCI:500,PVC,10.1.1.1,x,LMI500=Active400=Inactive,LMI标准,Cisco支持3种LMI标准:标准名称IOSlmi-type命令中的关键字CiscociscoANSIT1.617AnnexDansiITU-TQ.933AnnexAq933a,在IOS11.2以前，Cisco的缺省LMI类型是Cisco，在11.2以后则是与帧中继交换机进行协商。大多数公共交换电话网（PSTN）交换机被设置成自动检测LMI类型,LMI的配置,LMI的类型必须符合网络的LMI类型高版本的IOS软件可以自动检测LMI的类型,FrameRelay的反转ARP协议和LMI工作,FrameRelayCloud,1,DLCI=100,DLCI=400,172.168.5.5,172.168.5.7,Step1每个路由器连接到本地的帧中继交换机。,FrameRelay的反转ARP协议和LMI工作,2,StatusInquiry,2,StatusInquiry,FrameRelayCloud,1,DLCI=100,DLCI=400,172.168.5.5,172.168.5.7,Step2状态查询信息被发送到本地帧中继交换机。,FrameRelay的反转ARP协议和LMI工作,3,LocalDLCI100=Active,4,LocalDLCI400=Active,2,StatusInquiry,2,StatusInquiry,FrameRelayCloud,1,DLCI=100,DLCI=400,3,172.168.5.5,172.168.5.7,Step3本地帧中继交换机向路由器提供本地DLCI地址，同时指示出active/inactive状态。,FrameRelay的反转ARP协议和LMI工作,4,Hello,Iam172.168.5.5.,3,LocalDLCI100=Active,4,LocalDLCI400=Active,2,StatusInquiry,2,StatusInquiry,FrameRelayCloud,1,DLCI=100,DLCI=400,3,172.168.5.5,172.168.5.7,Step4路由器发送InverseARP信息。,FrameRelay的反转ARP协议和LMI工作,Hello,Iam172.168.5.7.,4,5,FrameRelayMap172.168.5.5DLCI400Active,FrameRelayCloud,DLCI=100,DLCI=400,FrameRelayMap172.168.5.7DLCI100Active,5,172.168.5.5,172.168.5.7,Step5InverseARP信息被用来建立一个动态的帧中继地址列表。,FrameRelay的反转ARP协议和LMI工作,Hello,Iam172.168.5.7.,4,5,FrameRelayMap172.168.5.5DLCI400Active,FrameRelayCloud,DLCI=100,DLCI=400,FrameRelayMap172.168.5.7DLCI100Active,5,Hello,Iam172.168.5.5.,6,172.168.5.5,172.168.5.7,Step6反映了InverseARP的周期间隔.(60s),FrameRelay的反转ARP协议和LMI工作,Keepalives,Keepalives,Hello,Iam172.168.5.7.,4,5,FrameRelayMap172.168.5.5DLCI400Active,FrameRelayCloud,DLCI=100,DLCI=400,FrameRelayMap172.168.5.7DLCI100Active,5,Hello,Iam172.168.5.5.,6,7,7,172.168.5.5,172.168.5.7,Step7发送keepalive信息(10s)。,Rel.11.2Router,Rel.10.3Router,interfaceSerial1ipaddress10.16.0.1255.255.255.0encapsulationframe-relaybandwidth64,interfaceSerial1ipaddress10.16.0.2255.255.255.0encapsulationframe-relaybandwidth64frame-relaylmi-typeansi,HQ,Branch,配置FrameRelay,反转ARP缺省情况下是激活的在配置输出信息中看不出来,Rel.11.2Router,Rel.10.3Router,HQ,interfaceSerial1ipaddress10.16.0.1255.255.255.0encapsulationframe-relaybandwidth64,interfaceSerial1ipaddress10.16.0.2255.255.255.0encapsulationframe-relaybandwidth64frame-relaylmi-typeansi,Branch,配置FrameRelay,DLCI=110IPaddress=10.16.0.1/24,p1r1,DLCI=100IPaddress=10.16.0.2/24,interfaceSerial1ipaddress10.16.0.1255.255.255.0encapsulationframe-relaybandwidth64frame-relaymapip10.16.0.2110broadcast,HQ,Branch,配置静态的FrameRelay映射,类似于静态路由，把对端的IP地址映射成本地的DLCI号码,查看FrameRelay信息,显示协议、DLCI、和LMI的相关信息,Router#showinterfaces0Serial0isup,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;inputqueue0/75,0drops,显示LMI信息,Router#showframe-relaylmiLMIStatisticsforinterfaceSerial0(FrameRelayDTE)LMITYPE=CISCOInvalidUnnumberedinfo0InvalidProtDisc0InvaliddummyCallRef0InvalidMsgType0InvalidStatusMessage0InvalidLockShift0InvalidInformationID0InvalidReportIELen0InvalidReportRequest0InvalidKeepIELen0NumStatusEnq.Sent113100NumStatusmsgsRcvd113100NumUpdateStatusRcvd0NumStatusTimeouts0,查看FrameRelay信息,显示路由信息,Router#showframe-relaymapSerial0(up):ip10.140.1.1dlci100(0 x64,0 x1840),dynamic,broadcast,statusdefined,active,查看FrameRelay信息,清除动态的FrameRelay映射关系,查看FrameRelay信息,Router#showframe-relaymapSerial0(up):ip10.140.1.1dlci100(0 x64,0 x1840),dynamic,broadcast,statusdefined,activeRouter#clearframe-relay-inarpRouter#shframemapRouter#,Star(HubandSpoke),FullMesh,PartialMesh,FrameRelaydefault:nonbroadcast,multiaccess(NBMA),选择FrameRelay拓扑结构,路由信息的可达性,S0,RouterB,RouterC,RouterD,RouterA,DLCI16toC,DLCI16toD,DLCI16toB,routerB通过routerA的串口S0转发路由更新信息给routerC,如果在路由器A的串口S0上分别映射三个DLCI到三台路由器，那么在路由器A的串口S0上的路由更新信息不会从该串口转发出去。,实现路由信息的可达性,解决方法:划分子端口可以解决水平分割造成的问题，从一个子接口收到路由更新信息后，可以从另一个子接口发送出去。在一个接口上执行encapsulationframe-relay后，该接口会自动禁止IP下的splithorizon。一个物理端口可以被划分成多个逻辑意义上的子端口,S0.1,RouterB,RouterC,RouterD,RouterA,Subnet2,Subnet3,Subnet1,S0.2,S0.3,子端口的配置命令,cisco(Optional)使用Cisco自己的封装格式（默认）。ietf(Optional)使封装格式符合IEFT标准，当连接使用其它厂商设备的帧中继网络时使用。,Router(config)#,interfaceinterface-typeinterface-number.subinterface-numbermultipointlpoint-to-point,定义子接口,FrameRelay映射,建立一个点对点子接口与DLCI的映射。不要在物理接口上使用此命令。,静态映射本地DLCI到目的网络层地址,A,10.17.0.1s0.2,B,配置点到点的子端口,interfaceSerial0noipaddressencapsulationframe-relay!interfaceSerial0.2point-to-pointipaddress10.17.0.1255.255.255.0bandwidth64frame-relayinterface-dlci110!interfaceSerial0.3point-to-pointipaddress10.18.0.1255.255.255.0bandwidth64frame-relayinterface-dlci120!,s0.310.18.0.1,C,10.17.0.2,10.18.0.2,DLCI=110,DLCI=120,仅仅在子接口上使用frame-relayinterface-dlci命令,配置点到点的子端口,interfaces0encapsulationframe-relay!interfaces0.1point-to-pointipaddress172.16.1.1255.255.255.0frame-relayinterface-dlci42!interfaces0.2point-to-pointipaddress172.16.4.1255.255.255.0frame-relayinterface-dlci53!Interfaces0.3point-to-pointipaddress172.16.2.10255.255.255.0frame-relayinterface-dlci59,DLCI36,FrameRelayNetwork,172.16.3.0,B,A,DLCI42,172.16.1.0,DLCI59,172.16.2.0,DLCI53,172.16.4.0,DLCI46,interfaceSerial2noipaddressencapsulationframe-relay!interfaceSerial2.2multipointipaddress10.17.0.1255.255.255.0bandwidth64frame-relaymapip10.17.0.2120broadcastframe-relaymapip10.17.0.3130broadcastframe-relaymapip10.17.0.4140broadcast,s2.1=10.17.0.2/24,s2.2=10.17.0.1/24,s2.1=10.17.0.4/24,s2.1=10.17.0.3/24,RTR1,B,RTR3,RTR4,多点子端口配置举例,DLCI=120,DLCI=130,DLCI=140,所有的连接都在同一子网内,多点子端口配置举例,interfaces0encapsulationframe-relay!interfaces0.1multipointipaddress172.16.1.1255.255.255.0frame-relayinterface-dlci300frame-relayinterface-dlci212frame-relayinterface-dlci437,interfaces0encapsulationframe-relay!interfaces0.1point-to-pointipaddress172.16.1.18255.255.255.0frame-relayinterface-dlci36,FrameRelay,B,A,172.16.1.2,172.16.1.3,D,C,DLCI36,了解FrameRelay工作过程配置FrameRelay配置FrameRelay的子端口查看FrameRelay信息,本章总结,完成本章的学习后，你应该能够掌握：,