第九章IP路由协议CICNDSA

第九章

IP

路由本章目标通过本章的学习，您应该掌握以下内容：

区分静态、动态路由的不同设置静态路由识别距离矢量的路由协议：RIP和IGRP设置RoutingInformationProtocol(RIP)设置InteriorGatewayRoutingProtocol(IGRP)利用show和debug命令查看IP路由信息要实现路由路由器必须知道:目的地址源地址所有可能的路由路径最佳路由路径管理路由信息什么是路由什么是路由Network

ProtocolDestination

NetworkConnected

Learned

10.120.2.0

172.16.1.0

ExitInterfaceE0

S0可路由协议:IP

路由器必须知道未和其直接相连的目的地址E0S0路由协议和可路由协议可路由协议(RoutedProtocol):利用网络层完成通信的协议，允许数据包从一个主机主机一寻址方案转发到另一主机。例如；IP；IPX；AppleTalk路由协议（RoutingProtocol):本质是创建和维护路由表，可路由协议利用他实现路由功能例如：RIP；IGRP；EIGRP；OSPF；BGP；IS-IS等；路由协议在网络层工作静态路由由网络管理员在路由器上手工添加路由信息以实现路由目的动态路由根据网络结构或流量的变化，路由协议会自动调整路由信息以实现路由静态路由和动态路由SO静态路由BNetworkA在小型网络中适宜设置静态路由。BStubNetwork指定一条可以到达目标网络的路径Router(config)#iproutenetwork[mask]

{address|interface}[distance][permanent]

静态路由的配置StubNetworkiproute172.16.1.0255.255.255.0172.16.2.1

SO静态路由的例子BNetworkAB这是一条单方向的路径，必须配置一条相反的路径。StubNetworkiproute0.0.0.00.0.0.0172.16.2.2

缺省路由SOBNetworkAB使用缺省路由后，StubNetwork可以到达路由器A以外的网络。路由协议路由协议

用于路由器选择路径和管理路由表。一旦选择了一条路径后，路由器将路由可路由协议。Network

ProtocolDestination

NetworkConnected

RIP

IGRP

ExitInterfaceE0

S0

S1可路由协议:IP

路由协议:RIP,IGRPE0S0自治系统100自治系统200IGPs:RIP,IGRPEGPs:BGP自治系统：内部和外部的

路由协议自治系统：使用相同的路由准则的网络的集合IGP在一个自治系统内运行。EGP连接不同的自治系统。路由的不可信度IGRP

AdministrativeDistance=100RouterDRouterBRouterARouterCRIP

AdministrativeDistance=120EIneedtosendapackettoNetworkE.BothrouterBandCwillgetitthere.

Whichrouteisbest?常用度量和metric值Hop;bandwidth;delay;load;reliability;ticks;cost度量值（Metric）：路协议算法由度量得出度量值。根据度量值判定路由最优路径，来创建和维护路由表。收敛时间收敛时间（convergencetime):从网络拓扑发生变化到网络中所有路由器都知道这个表化的时间就叫收敛时间路由协议的分类距离矢量混合路由链路状态CBADCDBA距离矢量的路由协议定期将路由表复制给相邻的路由器并且进行矢量堆加CDBACBADRoutingTableRoutingTableRoutingTableRoutingTableDistance—Howfar

Vector—Inwhichdirection路由器从收集到的源信息中选择到达目标地址的最佳路径ABCE0S0S0S1S0E0RoutingTable

00S0S1RoutingTableS00E00RoutingTable

E0S0

00距离矢量—源信息的获得路由器从收集到的源信息中选择到达目标地址的最佳路径ABCE0S0S0S1S0E0RoutingTableRoutingTable0011S0S1S1S0RoutingTableS00E00S0

1E0S0S0100距离矢量—源信息的获得距离矢量—源信息的获得路由器从收集到的源信息中选择到达目标地址的最佳路径ABCE0S0S0S1S0E0RoutingTableRoutingTable0011S0S1S1S0RoutingTableS00E00S0S012E0S0S0S01200

距离矢量—选择最佳路径用于确定最佳路由路径的参数信息56T156T1Ticks,hopcountBAHopcountIPXRIPIGRPBandwidthDelayLoadReliabilityMTU距离矢量—管理路由信息路由表的更新过程将通过路由器之间一步一步来完成A更新路由表网络结构的改变将导致路由表的更新距离矢量—管理路由信息路由表的更新过程将通过路由器之间一步一步来完成A更新路由表在下一个周期后路由器A发送更新过的路由表网络结构的改变将导致路由表的更新距离矢量—管理路由信息路由表的更新过程将通过路由器之间一步一步来完成AB更新路由表更新路由表网络结构的改变将导致路由表的更新在下一个周期后路由器A发送更新过的路由表路由回环每一个节点管理着与之相连的所有网络ABCE0S0S0S1S0E0RoutingTableS0E0S0S01200RoutingTableE0S0S0S01200RoutingTableS0S1S1S01100路由回环缓慢的收敛容易造成路由信息的不一致ABCE0S0S0S1S0E0XRoutingTableS0E0S0S0120DownRoutingTableE0S0S0S01200RoutingTableS0S1S1S01100路由器C推断到达10.4.0.0网络的最好路径是通过路由器B路由回环ABCE0S0S0S1S0E0XRoutingTable10.3.0.0S0S0S0S01210.1.0.010.2.0.010.4.0.002RoutingTable10.1.0.0E0S0S0S01210.4.0.010.3.0.010.2.0.000RoutingTable10.2.0.0S0S1S1S11110.1.0.010.4.0.010.3.0.000路由器A根据错误的信息升级它的路由表路由回环ABCE0S0S0S1S0E0XRoutingTableS0S0S0S01210.3.0.010.1.0.010.2.0.010.4.0.002RoutingTableE0S0S0S01410.1.0.010.4.0.010.3.0.010.2.0.000RoutingTableS0S1S1S03110.2.0.010.1.0.010.4.0.010.3.0.000无限计数10.4.0.0网络的数据将在路由器A,B,和C之间循环10.4.0.0网络的跳数将无限大ABCE0S0S0S1S0E0XRoutingTableS0S0S0S01204RoutingTableE0S0S0S01610.1.0.010.4.0.010.3.0.010.2.0.000RoutingTableS0S1S1S05110.2.0.010.1.0.010.4.0.010.3.0.000解决方法：定义最大跳数指定最大跳数来防止路由回环ABCE0S0S0S1S0E0XRoutingTable10.3.0.0S0S0S0S01210.1.0.010.2.0.010.4.0.0016RoutingTableE0S0S0S011610.1.0.010.4.0.010.3.0.010.2.0.000RoutingTableS0S1S1S016110.2.0.010.1.0.010.4.0.010.3.0.000解决方法：水平分割不会接收到由自身传达出去的路由信息ABCE0S0S0S1S0E0XXXRoutingTable10.3.0.0S0S0S0S01210.1.0.010.2.0.010.4.0.000RoutingTableE0S0S0S01210.1.0.010.4.0.010.3.0.010.2.0.000RoutingTableS0S1S1E11210.2.0.010.1.0.010.4.0.010.3.0.000解决方法：路由毒杀路由器将该路由信息的跳数标记为无限大ABCE0S0S0S1S0E0XRoutingTable10.3.0.0S0S0S0S01210.1.0.010.2.0.010.4.0.00InfinityRoutingTable10.1.0.0E0S0S0S01210.4.0.010.3.0.010.2.0.000RoutingTable10.2.0.0S0S1S1E11210.1.0.010.4.0.010.3.0.000解决方法：反转毒杀反转毒杀可以超越水平分割ABCE0S0S0S1S0E0XRoutingTable10.3.0.0S0S0S0S01210.1.0.010.2.0.010.4.0.00InfinityRoutingTable10.1.0.0E0S0S0S01210.4.0.010.3.0.010.2.0.000RoutingTable10.2.0.0S0S1S1E1Possibly

Down210.1.0.010.4.0.010.3.0.000Poison

Reverse解决方法：Hold-Down计时路由器在Hold-Down时间内将该条记录标记为possiblydown以使其它路由器能够重新计算网络结构的变化Network10.4.0.0isdownthenbackupthenbackdownUpdateafterhold-downTimeisunreachableABCE0S0S0S1S0E0XUpdateafterhold-downTime解决方法：触发更新当路由表发生变化时路由器立即发送更新信息ABCE0S0S0S1S0E0Xisunreachableisunreachableisunreachable环路解决方法组合应用1d19h:subnet10.可路由协议(RoutedProtocol):利用网络层完成通信的协议，允许数据包从一个主机主机一寻址方案转发到另一主机。UpdateafterRoutingTable配置IGRP(续)00:31:15:IGRP:editionisnow3RoutingTable0/24issubnetted,2subnets在Cisco路由器上设置RIP和IGRP路由协议debugiprip命令1onSerial2区分静态、动态路由的不同1d19h:IGRP:editionisnow10Connected

RIP

IGRPIGRP协议比RIP协议有什么优点？0isdirectlyconnected,Serial3距离矢量和环状路由的综合应用一个完整的方案DBEAXC一个完整的方案DBEACXHolddownHolddownHolddown一个完整的方案DBEACXHolddownHolddownHolddownPoisonReversePoisonReversePoisonReversePoisonReverse一个完整的方案DBEACXHolddownHolddownHolddownPacketforPacketfor一个完整的方案DBEACLinkup!一个完整的方案DBEACLinkup!链路状态协议原理1：路由器找到自己邻居2：每个路由器想邻居发送LSAlinkstateadvertisement数据包，包含了自己的路径成本3：LSA扩散，每个路由器都得到相同拓扑结构的数据库4：由SPF算法计算网络可达性，建立SPF树，以自己为树根5：创建路由表，列出最优路径列表；维护其他拓扑结构和状态细节数据库。链路状态协议传递最佳的路径信息给其它的路由器LSA（linkstateadvertisement)数据包链路状态公告SPF运算拓补结构数据最佳路由信息路由表CADB链路状态协议特点距离矢量和环状路由的综合应用混合路由选择基于距离矢量的路径Convergerapidlyusing通过传递变化的更新信息达到快速收敛平衡的路由路由器配置选择路由协议指定网络或端口NetworkIGRP,RIPRIPRIPIGRPIP路由的配置任务指定IP路由协议Router(config)#routerprotocol[keyword]

指定与路由器直接相连的网络Router(config-router)#networknetwork-number动态路由配置19.2kbpsT1T1T1Hop计算路由器每隔30秒更新最多支持相同hop数的6条路径RIP概述激活RIP协议Router(config)#routerripRouter(config-router)#networknetwork-number选择所能到达的网络必须是有效的网络RIP配置routerripnetwork172.16.0.0network10.0.0.0RIP配置举例routerripnetwork10.0.0.0routerripnetwork192.168.1.0network10.0.0.0S2E0S3S2S3ABC192.168.1.0E0查看RIP信息RouterA#shipprotocolsRoutingProtocolis"rip"Sendingupdatesevery30seconds,nextduein0secondsInvalidafter180seconds,holddown180,flushedafter240OutgoingupdatefilterlistforallinterfacesisIncomingupdatefilterlistforallinterfacesisRedistributing:ripDefaultversioncontrol:sendversion1,receiveanyversionInterfaceSendRecvKey-chainEthernet0112Serial2112RoutingforNetworks:RoutingInformationSources:GatewayDistanceLastUpdate10.1.1.212000:00:10Distance:(defaultis120)S2E0S3S2S3ABC192.168.1.0E0查看路由表RouterA#shiprouteCodes:C-connected,S-static,I-IGRP,R-RIP,M-mobile,B-BGPD-EIGRP,EX-EIGRPexternal,O-OSPF,IA-OSPFinterareaN1-OSPFNSSAexternaltype1,N2-OSPFNSSAexternaltype2E1-OSPFexternaltype1,E2-OSPFexternaltype2,E-EGPi-IS-IS,L1-IS-ISlevel-1,L2-IS-ISlevel-2,*-candidatedefaultU-per-userstaticroute,o-ODRT-trafficengineeredrouteGatewayoflastresortisnotset172.16.0.0/24issubnetted,1subnetsC172.16.1.0isdirectlyconnected,Ethernet010.0.0.0/24issubnetted,2subnetsR10.2.2.0[120/1]via10.1.1.2,00:00:07,Serial2C10.1.1.0isdirectlyconnected,Serial2R192.168.1.0/24[120/2]via10.1.1.2,00:00:07,Serial2S2E0S3S2S3ABC192.168.1.0E0debugiprip

命令RouterA#debugipripRIPprotocoldebuggingisonRouterA#00:06:24:RIP:receivedv1updatefrom10.1.1.2onSerial200:06:24:10.2.2.0in1hops00:06:24:192.168.1.0in2hops00:06:33:RIP:sendingv1updateto255.255.255.255viaEthernet0(172.16.1.1)00:06:34:network10.0.0.0,metric100:06:34:network192.168.1.0,metric300:06:34:RIP:sendingv1updateto255.255.255.255viaSerial2(10.1.1.1)00:06:34:network172.16.0.0,metric1S2E0S3S2S3ABC192.168.1.0E0使用IGRP的网络较大缺省100hops，最大255hops支持多路径IGRP介绍IGRP带宽延迟时间可靠性负载最大传输单元19.2kbps19.2kbpsIGRP路径选择SourceDestination最多六条路径下一次所要到达的路由器必须接近目的网络在允许的参数内选择路径NewRouteInitial

RouteSourceDestinationIGRP的不平衡路径配置IGRPRouter(config-router)#networknetwork-number指定可以到达的网络Router(config)#routerigrpautonomous-system指定IGRP为IP路由协议配置IGRP(续)Router(config-router)#traffic-share

{balanced|min}控制负载平衡数据的分布Router(config-router)#variancemultiplier控制IGRP的负载平衡routerigrp100IGRP配置举例routerigrp100routerigrp100AutonomousSystem=100S2E0S3S2S3ABC192.168.1.0E0查看IGRP信息RouterA#shipprotocolsRoutingProtocolis"igrp100"Sendingupdatesevery90seconds,nextduein21secondsInvalidafter270seconds,holddown280,flushedafter630OutgoingupdatefilterlistforallinterfacesisIncomingupdatefilterlistforallinterfacesisDefaultnetworksflaggedinoutgoingupdatesDefaultnetworksacceptedfromincomingupdatesIGRPmetricweightK1=1,K2=0,K3=1,K4=0,K5=0IGRPmaximumhopcount100IGRPmaximummetricvariance1Redistributing:igrp100RoutingforNetworks:RoutingInformationSources:GatewayDistanceLastUpdate10.1.1.210000:01:01Distance:(defaultis100)S2E0S3S2S3ABC192.168.1.0E0查看IP路由表RouterA#shiprouteCodes:C-connected,S-static,I-IGRP,R-RIP,M-mobile,B-BGPD-EIGRP,EX-EIGRPexternal,O-OSPF,IA-OSPFinterareaN1-OSPFNSSAexternaltype1,N2-OSPFNSSAexternaltype2E1-OSPFexternaltype1,E2-OSPFexternaltype2,E-EGPi-IS-IS,L1-IS-ISlevel-1,L2-IS-ISlevel-2,*-candidatedefaultU-per-userstaticroute,o-ODRT-trafficengineeredrouteGatewayoflastresortisnotset172.16.0.0/24issubnetted,1subnetsC172.16.1.0isdirectlyconnected,Ethernet010.0.0.0/24issubnetted,2subnetsI10.2.2.0[100/90956]via10.1.1.2,00:00:23,Serial2C10.1.1.0isdirectlyconnected,Serial2I192.168.1.0/24[100/91056]via10.1.1.2,00:00:23,Serial2S2E0S3S2S3ABC192.168.1.0E0debugipigrptransaction

命令RouterA#debugipigrptransactionsIGRPprotocoldebuggingisonRouterA#00:21:06:IGRP:sendingupdateto255.255.255.255viaEthernet0(172.16.1.1)00:21:06:network10.0.0.0,metric=8895600:21:06:network192.168.1.0,metric=9105600:21:07:IGRP:sendingupdateto255.255.255.255viaSerial2(10.1.1.1)00:21:07:network172.16.0.0,metric=110000:21:16:IGRP:receivedupdatefrom10.1.1.2onSerial200:21:16:subnet10.2.2.0,metric90956(neighbor88956)00:21:16:network192.168.1.0,metric91056(neighbor89056)S2E0S3S2S3ABC192.168.1.0E0debugipigrpevents

命令RouterA#debugipigrpeventsIGRPeventdebuggingisonRouterA#00:23:44:IGRP:sendingupdateto255.255.255.255viaEthernet0(172.16.1.1)00:23:44:IGRP:Updatecontains0interior,2system,and0exteriorroutes.00:23:44:IGRP:Totalroutesinupdate:200:23:44:IGRP:sendingupdateto255.255.255.255viaSerial2(10.1.1.1)00:23:45:IGRP:Updatecontains0interior,1system,and0exteriorroutes.00:23:45:IGRP:Totalroutesinupdate:100:23:48:IGRP:receivedupdatefrom10.1.1.2onSerial200:23:48:IGRP:Updatecontains1interior,1system,and0exteriorroutes.00:23:48:IGRP:Totalroutesinupdate:2S2E0S3S2S3ABC192.168.1.0E0路由信息更新举例RouterA#debugipigrptrans00:31:15:%LINEPROTO-5-UPDOWN:LineprotocolonInterfaceEthernet0,changedstatetodown00:31:15:IGRP:editionisnow300:31:15:IGRP:sendingupdateto255.255.255.255viaSerial2(10.1.1.1)00:31:15:network172.16.0.0,metric=429496729500:31:16:IGRP:Updatecontains0interior,1system,and0exteriorroutes.00:31:16:IGRP:Totalroutesinupdate:100:31:16:IGRP:broadcastingrequestonSerial200:31:16:IGRP:receivedupdatefrom10.1.1.2onSerial200:31:16:subnet10.2.2.0,metric90956(neighbor88956)00:31:16:network172.16.0.0,metric4294967295(inaccessible)00:31:16:network192.168.1.0,metric91056(neighbor89056)00:31:16:IGRP:Updatecontains1interior,2system,and0exteriorroutes.00:31:16:IGRP:Totalroutesinupdate:3S2E0S3S2S3ABC192.168.1.0E0X路由信息更新举例RouterB#debugipigrptransIGRPprotocoldebuggingisonRouterB#1d19h:IGRP:sendingupdateto255.255.255.255viaSerial2(10.1.1.2)1d19h:subnet10.2.2.0,metric=889561d19h:network192.168.1.0,metric=890561d19h:IGRP:sendingupdateto255.255.255.255viaSerial3(10.2.2.2)1d19h:subnet10.1.1.0,metric=889561d19h:network172.16.0.0,metric=890561d19h:IGRP:receivedupdatefrom10.1.1.1onSerial21d19h:network172.16.0.0,metric4294967295(inaccessible)1d19h:IGRP:editionisnow101d19h:IGRP:sendingupdateto255.255.255.255viaSerial2(10.1.1.2)1d19h:subnet10.2.2.0,metric=889561d19h:network172.16.0.0,metric=42949672951d19h:network192.168.1.0,metric=890561d19h:IGRP:sendingupdateto255.255.255.255viaSerial3(10.2.2.2)1d19h:subnet10.1.1.0,metric=889561d19h:network172.16.0.0,metric=4294967295S2E0S3S2S3ABC192.168.1.0E00,metric=88956C10.0,metric90956(neighbor88956)指定IGRP为IP路由协议配置IGRP(续)T-trafficengineeredroute255viaEthernet0(172.network10.RoutingTable指定最大跳数来防止路由回环RoutingInformationSources:区分静态、动态路由的不同RoutingTable0,metric1RoutingTable根据网络结构或流量的变化，路由协议会自动调整路由信息以实现路由路由信息更新举例RouterB#shiprouteCodes:C-connected,S-static,I-IGRP,R-RIP,M-mobile,B-BGPD-EIGRP,EX-EIGRPexternal,O-OSPF,IA-OSPFinterareaN1-OSPFNSSAexternaltype1,N2-OSPFNSSAexternaltype2E1-OSPFexternaltype1,E2-OSPFexternaltype2,E-EGPi-IS-IS,L1-IS-ISlevel-1,L2-IS-ISlevel-2,*-candidatedefaultU-per-userstaticroute,o-ODRT-trafficengineeredrouteGatewayoflastresortisnotsetI172.16.0.0/16ispossiblydown,routingvia10.1.1.1,Serial210.0.0.0/24issubnetted,2subnetsC10.1.1.0isdirectlyconnected,Serial2C10.2.2.0isdirectlyconnected,Serial3I192.168.1.0/24[100/89056]via10.2.2.3,00:00:14,Serial3Typeescapesequencetoabort.Sending5,100-byteICMPEchosto172.16.1.1,timeoutis2seconds:.....Successrateis0percent(0/5)RouterB#S2E0S3S2S3ABC192.168.1.0E0X路由信息更新举例S2E0S3S2S3ABC192.168.1.0E0RouterB#debugipigrptransactionsRouterB#1d20h:IGRP:receivedupdatefrom10.1.1.1onSerial21d20h:network172.16.0.0,metric89056(neighbor1100)RouterB#RouterB#shiprouteCodes:C-connected,S-static,I-IGRP,R-RIP,M-mobile,B-BGPD-EIGRP,EX-EIGRPexternal,O-OSPF,IA-OSPFinterareaN1-OSPFNSSAexternaltype1,N2-OSPFNSSAexternaltype2E1-OSPFexternaltype1,E2-OSPFexternaltype2,E-EGPi-IS-IS,L1-IS-ISlevel-1,L2-IS-ISlevel-2,*-candidatedefaultU-per-userstaticroute,o-ODRT-trafficengineeredrouteGatewayoflast