思科路由协议培训.ppt

Configuring EIGRP,Objectives,Upon completing this lesson,you will be able to:Describe EIGRP features and operationExplain how EIGRP discovers,chooses,and maintains routesExplain how EIGRP supports the use of VLSMExplain how EIGRP operates in an NBMAenvironmentExplain how EIGRP supports the use of routesummarization,Objectives(cont.),Describe how EIGRP supports large networks Configure EIGRPVerify EIGRP operationConfigure an EIGRP environment and verify proper operation(within described guidelines)of your routers,given a set of network requirements Configure EIGRP in an NBMA environment and verify proper operation(within described guidelines)of your routers,given a set of network requirements,EIGRP Overview,2001,Cisco Systems,Inc.,4-4,EIGRP supports:Rapid convergenceReduced bandwidth usageMultiple network-layer protocols,What Is EIGRP?,EnhancedIGRP,IPX RoutingProtocols,AppleTalk Routing Protocol,IP RoutingProtocols,IPX RoutingProtocols,AppleTalk Routing Protocol,IP RoutingProtocols,EIGRP Features,Advanced distance vector100%loop freeFast convergenceEasy configurationLess network design constraints than OSPF,EIGRP Features(cont.),Incremental updatesSupports VLSM and discontiguous networksClassless routingCompatible with existing IGRP networksProtocol independent(supports IPX and AppleTalk),Advantages of EIGRP,Multicast instead of broadcastUse of link bandwidth and delay EIGRP metric=IGRP metric x 256(32 bit versus 24 bit)Unequal cost path load balancingMore flexible than OSPF Manual summarization can be done in any interface at any router within the network,EIGRP in IP Packets,EIGRP is an advanced distance vector routing protocol:Automatically establishes neighbor relationships with peer devicesRelies on IP packets for delivery of routing information,IP Header,Protocol Number,Frame Header,CRC,Packet Payload,Frame Payload,88EIGRP 6TCP17UDP,EIGRP Support for Different Topologies,EIGRP supportsMultiaccess(LANs)Point-to-point(HDLC)NBMA(Frame Relay),S0,A,B,S1,E,F,G,H,FrameRelay,D,C,Rest of the Core,EIGRP Support for IP Addresses,EIGRP supports:VLSMsHierarchical designs,/16,D,/27,/30,/24,World,N,M,A,P,O,B,S,R,C,EIGRP Support for Route Summarization,EIGRP performs route summarizationClassful network boundaries(default)Arbitrary network boundaries(manual),172.16.0.0/24,10.0.0.0/18,192.168.42.0/27,172.16.0.0/16,172.16.0.0/16192.168.42.0/24,EIGRP Terminology,Neighbor TableAppleTalkDestination Next Hop Router,Neighbor TableIPXDestination Next Hop Router,Neighbor TableIPNext-Hop Interface Router,EIGRP Terminology(cont.),Neighbor TableAppleTalkDestination Next Hop Router,Neighbor TableIPXDestination Next Hop Router,Neighbor TableIPNext-Hop Interface Router,EIGRP Terminology(cont.),Neighbor TableAppleTalkDestination Next Hop Router,Neighbor TableIPXDestination Next Hop Router,Neighbor TableIPNext-Hop Interface Router,EIGRP Terminology(cont.),Neighbor TableAppleTalkDestination Next Hop Router,Neighbor TableIPXDestination Next Hop Router,Neighbor TableIPNext-Hop Interface Router,EIGRP Terminology(cont.),Neighbor TableAppleTalkDestination Next Hop Router,Neighbor TableIPXDestination Next Hop Router,Neighbor TableIPNext-Hop Interface Router,EIGRP Operation,2001,Cisco Systems,Inc.,4-18,EIGRP Packets,Hello:Establish neighbor relationshipsUpdate:Send routing updatesQuery:Ask neighbors aboutrouting informationReply:Response to query aboutrouting informationACK:Acknowledgment of a reliable packet,EIGRP Neighbor Relationship,Two routers become neighbors when they see each others hello packetHello address=224.0.0.10Hellos sent once every 5 seconds on the following links:Broadcast media:Ethernet,Token Ring,FDDIPoint-to-point serial links:PPP,HDLC,point-to-point Frame Relay/ATM subinterfacesMultipoint circuits with bandwidth greater than T1:ISDN PRI,SMDS,Frame Relay,EIGRP Neighbor Relationship(cont.),Hellos sent once every 60 seconds on the following links:Multipointcircuits with bandwidth less than or equal to T1:ISDN BRI,Frame Relay,SMDS,and so onNeighbor declared dead when no EIGRP packets are received within hold intervalHold time by default is three times the hello time,EIGRP Neighbor Relationship(cont.),EIGRP will form neighbors even though hello time and hold time dont match EIGRP sources hello packets from primary address of the interfaceEIGRP will not form neighbor if K-values are mismatchedEIGRP will not form neighbor if AS numbers are mismatched,What Is in a Neighbor Table?,p2r2,p2r2#show ip eigrp neighborsIP-EIGRP neighbors for process 400H Address Interface Hold Uptime SRTT RTO Q Seq(sec)(ms)Cnt Num1 172.68.2.2 To0 13 02:15:30 8 200 0 90 172.68.16.2 Se1 10 02:38:29 29 200 0 6,EIGRP Reliability,EIGRP reliable packets are packets that require explicit acknowledgment:UpdateQueryReplyEIGRP unreliable packets are packets that do not require explicit acknowledgment:HelloACK,EIGRP Reliability(cont.),The router keeps a neighbor list and a retransmission list for every neighbor Each reliable packet(update,query,reply)will be retransmitted when packet is not acknowledgedNeighbor relationship is reset when retry limit(limit=16)for reliable packets is reached,EIGRP Reliability(cont.),EIGRP transport has window size of one(stop-and-wait mechanism)Every single reliable packet needs to be acknowledged before the next sequenced packet can be sent If one or more peers are slow in acknowledging,all other peers sufferSolution:The nonacknowledged multicast packet will be retransmitted as a unicast to the slow neighbor,I am router A,who is on the link?,Hello,A,B,1,Initial Route Discovery,Here is my complete routing information.,Update,2,Initial Route Discovery(cont.),I am router A,who is on the link?,Hello,A,B,1,Thanks for the information!,Ack,3,Initial Route Discovery(cont.),Here is my complete routing information.,Update,2,I am router A,who is on the link?,Hello,A,B,1,Topology Table,3,4,Initial Route Discovery(cont.),Thanks for the information!,Ack,3,Here is my complete routing information.,Update,2,I am router A,who is on the link?,Hello,A,B,1,3,4,Thanks for the information!,Ack,3,Here is my complete routing information.,Update,2,I am router A,who is on the link?,Hello,A,B,1,Initial Route Discovery(cont.),Here is my complete route information.,Update,Topology Table,5,Initial Route Discovery(cont.),Converged,Thanks for the information!,Ack,6,3,4,Thanks for the information!,Ack,3,Here is my complete routing information.,Update,2,I am router A,who is on the link?,Hello,B,1,Here is my complete route information.,Update,5,Topology Table,A,EIGRP uses a composite metric to pick the best path,EIGRP Route Selection,IPX,19.2,T1,T1,T1,IPX,AppleTalk,IP,AppleTalk,IP,A,B,D,C,EIGRP Metrics Calculation,Metric=K1 x BW+(K2 x BW)/(256 load)+K3 x delay x K5/(reliability+K4)By default:K1=1,K2=0,K3=1,K4=0,K5=0Delay is sum of all the delays of the links along the pathsDelay=Delay in 10s of microseconds x 256BW=the lowest bandwidth of the links along the pathsBW=10000000/(bandwidth in Kbps)x 256By default,metric=BW+delay,EIGRP DUAL,Diffusing Update Algorithm(DUAL)Finite-state machineTracks all routes advertised by neighborsSelects loop-free path using a successor and remembers any feasible successorsIf successor lost:Use feasible successorIf no feasible successor:Query neighbors and recompute new successor,DUAL Example(Start),E EIGRP FD AD Topology(a)3(fd)via D 3 2(Successor)via C 4 3,D EIGRP FD AD Topology(a)2(fd)via B 2 1(Successor)via C 5 3,C EIGRP FD AD Topology(a)3(fd)via B 3 1(Successor)via D 4 2(fs)via E 4 3,(1),(1),(1),(1),(2),(2),(a),A,E,D,C,B,DUAL Example,(1),(1),(1),(1),(2),(2),(a),A,E,D,C,B,E EIGRP FD AD Topology(a)3(fd)via D 3 2(Successor)via C 4 3,D EIGRP FD AD Topology(a)2(fd)via B 2 1(Successor)via C 5 3,C EIGRP FD AD Topology(a)3(fd)via B 3 1(Successor)via D 4 2(fs)via E 4 3,X,DUAL Example(cont.),Q,Q,(1),(1),(1),(2),(2),(a),A,E,D,C,B,E EIGRP FD AD Topology(a)3(fd)via D 3 2(Successor)via C 4 3,D EIGRP FD AD Topology(a)*ACTIVE*-1(fd)via E(q)via C 5 3(q),C EIGRP FD AD Topology(a)3(fd)via B 3 1(Successor)via Dvia E 4 3,DUAL Example(cont.),R,Q,(1),(1),(1),(2),(2),(a),A,E,D,C,B,E EIGRP FD AD Topology(a)*ACTIVE*-1(fd)via D via C 4 3(q),D EIGRP FD AD Topology(a)*ACTIVE*-1(fd)via E(q)via C 5 3,C EIGRP FD AD Topology(a)3(fd)via B 3 1(Successor)via D via E,DUAL Example(cont.),R,(1),(1),(1),(2),(2),(a),A,E,D,C,B,E EIGRP FD AD Topology(a)4(fd)via C 4 3(Successor)via D,D EIGRP FD AD Topology(a)*ACTIVE*-1(fd)via E(q)via C 5 3,C EIGRP FD AD Topology(a)3(fd)via B 3 1(Successor)via Dvia E,DUAL Example(cont.),R,(1),(1),(1),(2),(2),(a),A,E,B,E EIGRP FD AD Topology(a)4(fd)via C 4 3(Successor)via D,D EIGRP FD AD Topology(a)5(fd)via C 5 3(Successor)via E 5 4(Successor),C EIGRP FD AD Topology(a)3(fd)via B 3 1(Successor)via Dvia E,D,C,DUAL Example(cont.),(1),(1),(1),(2),(2),(a),A,E,D,C,B,E EIGRP FD AD Topology(a)4(fd)via C 4 3(Successor)via D,D EIGRP FD AD Topology(a)5(fd)via C 5 3(Successor)via E 5 4(Successor),C EIGRP FD AD Topology(a)3(fd)via B 3 1(Successor)via Dvia E,DUAL Example(Start),(1),(1),(1),(1),(2),(2),(a),A,E,D,C,B,E EIGRP FD AD Topology(a)3(fd)via D 3 2(Successor)via C 4 3,D EIGRP FD AD Topology(a)2(fd)via B 2 1(Successor)via C 5 3,C EIGRP FD AD Topology(a)3(fd)via B 3 1(Successor)via D 4 2(fs)via E 4 3,DUAL Example(End),(1),(1),(1),(2),(2),(a),A,E,D,C,B,E EIGRP FD AD Topology(a)4(fd)via C 4 3(Successor)via D,D EIGRP FD AD Topology(a)5(fd)via C 5 3(Successor)via E 5 4(Successor),C EIGRP FD AD Topology(a)3(fd)via B 3 1(Successor)via Dvia E,Written Exercise,2001,Cisco Systems,Inc.,4-45,Configuring EIGRP,2001,Cisco Systems,Inc.,4-46,Configuring EIGRP for IP,S2,router eigrp 109network 10.0.0.0network 172.16.0.0,10.1.0.0,10.2.0.0,172.16.4.0,172.16.3.0,172.16.2.0,172.16.7.0,10.4.0.0,172.16.6.0,172.16.5.0,172.16.1.0,T0,S0,S1,192.168.1.0,Network 192.168.0.0 is not configured on Router A because it is not directly connected to Router A,AS=109,B,C,D,A,E,EIGRP SummarizationAutomatic,Purpose:Smaller routing tables,smaller updates,query boundaryAutosummarization:On major network boundaries,subnetworks are summarized to a single classful(major)networkAutosummarization is turned on by default,172.16.X.X,172.16.0.0/16,172.17.X.X,EIGRP SummarizationManual,Manual summarizationConfigurable on a per-interface basis in anyrouter within networkWhen summarization is configured on an interface,the router immediately creates a route pointing to Null0Loop prevention mechanismWhen the last specific route of the summary goes away,the summary is deletedThe minimum metric of the specific routes is used as the metric of the summary route,Configuring Summarization,(config-router)#,no auto-summary,Turns off autosummarization for the EIGRP process,(config-if)#,ip summary-address eigrp as-number address mask,Creates a summary address to be generatedby this interface,Summarizing EIGRP Routes,router eigrp 1,network 10.0.0.0,network 172.16.0.0,no auto-summary,172.16.1.0,172.16.2.0,192.168.4.2,S0,World,10.0.0.0,A,B,C,Summarizing EIGRP Routes(cont.),router eigrp 1,network 10.0.0.0network 192.168.4.0,!int s0 ip address 192.168.4.2 255.255.255.0,ip summary-address eigrp 1,172.16.0.0 255.255.0.0,router eigrp 1,network 10.0.0.0,network 172.16.0.0,no auto-summary,172.16.1.0,172.16.2.0,192.168.4.2,S0,World,10.0.0.0,A,B,C,EIGRP Load Balancing,Routes with metric equal to the minimum metric will be installed in the routing table(equal-cost load balancing)Up to six entries in the routing table for the same destinationNumber of entries is configurableDefault is four,EIGRP Unequal-Cost Load Balancing,EIGRP offers unequal-cost load balancingvariance commandVariance allows the router to include routes with a metric smaller than multiplier times the minimum metric route to that destinationMultiplier is the number specified by the variance command,10,20,10,10,20,25,variance 2,Variance Example,Router E will choose Router C to get to Network Z because FD=20With variance of 2,Router E will also choose Router B to get to Network Z(20+10)40),Network Z,(config-router)#,A,E,D,C,B,Configuring WAN Links,EIGRP supports different WAN linksPoint-to-pointNBMAMultipointPoint-to-pointEIGRP configurations must addressBandwidth useOverhead traffic associated with router operation,EIGRP Bandwidth Use,Specifies what percentage of bandwidth that EIGRP packets will be able to use on this interfaceUses up to 50 percent of the link bandwidth for EIGRP packets,by default Used for greater EIGRP load control,(config-if)#,ip bandwidth-percent eigrp as-number nnn,Bandwidth over WAN Interfaces,Bandwidth use over point-to-point subinterfaces using Frame RelayTreats bandwidth as T1,by defaultBest practice is to manually configure bandwidth as the CIR of the PVC,Bandwidth over WAN Interfaces(cont.),Bandwidth over multipoint Frame Relay,ATM,SMDS,and ISDN PRI:EIGRP uses the bandwidth on the main interface divided by the number of neighbors on that interface to get the bandwidth information per neighbor,Bandwidth over WAN Interfaces(cont.),Each PVC might have a different CIR,creating an EIGRP packet-pacing problemMultipoint interfaces:Convert to point-to-point configuration orManually configure bandwidth=lowest CIR x number of PVCs,EIGRP WAN ConfigurationPure Multipoint,CIR 56,C,E,F,G,H,FrameRelay,S0,CIR 56,CIR 56,CIR 56,T1,interface serial 0 encap frame-relay bandwidth 224,All VCs share bandwidth evenly:4 x 56=224,EIGRP WAN Configuration Hybrid Multipoint,CIR 256BW 224,C,E,F,G,H,FrameRelay,S0,CIR 256BW 224,CIR 256BW 224,CIR 56BW 56,T1,Lowest CIR x#of VCs:56 x 4=224,interface serial 0 encap frame-relay bandwidth 224,EIGRP WAN Configuration Hybrid Multipoint(Preferred),CIR 256BW 256,FrameRelay,S0,CIR 256BW 256,CIR 256BW 256,CIR 56BW 56,interface serial 0.1 multipoint bandwidth 768interface serial 0.2 point-to-point bandwidth 56,Configure lowest CIR VC as point-to-point,specify BW=CIRConfigure higher CIR VCs as multipoint,combine CIRs,S0.1,S0.2,C,T1,E,F,G,H,EIGRP WAN ConfigurationPure Point-to-Point,CIR 56BW 25,C,E,F,G,H,FrameRelay,S0,CIR 56BW 25,CIR 56BW 25,CIR 56BW 25,256,interface serial 0.1 point-to-point bandwidth 25 ip bandwidth-percent eigrp 63 110-interface serial 0.10 point-to-point bandwidth 25 ip bandwidth-percent eigrp 63 110,Configure each VC as point-to-point,specify BW=1/10 of link capacityIncrease EIGRP use to 50 percent of actual VC capacity,interface serial 0 bandwidth 25 ip bandwidth-percent eigrp 63 110,Hub and Spokewith 10 x VCs,Using EIGRP inScalable Internetworks,2001,Cisco Systems,Inc.,4-65,Factors That InfluenceEIGRP Scalability,EIGRP is not plug-and-play for large networksLimit EIGRP query range!Quantity of routing information exchanged between peersAdvertise major network or default route to regions or remotes,EIGRP Query Process,Queries are sent out when a route is lost and no feasible successor is availableThe lost route is now in active stateQueries are sent out to all of its neighbors on all interfaces except the interface to the successorIf the neighbors do not have the lost route information,queries are sent out to thei