Introducing EIGRP参考.ppt

Configuring EIGRP Introducing EIGRP EIGRP Features EIGRP Key Technologies Neighbor discovery/recovery Uses hello packets between neighbors Reliable Transport Protocol (RTP) Guaranteed, ordered delivery of EIGRP packets to all neighbors DUAL finite-state machine Selects lowest-cost, loop free, paths to each destination Protocol-dependent modules (PDMs) EIGRP supports IP, AppleTalk, and Novell NetWare. Each protocol has its own EIGRP module and operates independently of any of the others that may be running. EIGRP Neighbor Table DUAL Terminology Selects lowest-cost, loop-free paths to each destination AD = cost between the next-hop router and the destination FD = cost from local router = AD of next-hop router + cost between the local router and the next-hop router Lowest-cost = lowest FD (Current) successor = next-hop router with lowest-cost, loop free path Feasible successor = backup router with loop-free path (AD of feasible successor must be less than FD of current successor route) EIGRP Topology Table EIGRP IP Routing Table Example: EIGRP Tables EIGRP Packets Hello: Establish neighbor relationships. Update: Send routing updates. Query: Ask neighbors about routing information. Reply: Respond to query about routing information. ACK: Acknowledge a reliable packet. EIGRP Hello Packets EIGRP Hello Timers Hellos sent once every 5 seconds on the following links: Broadcast media: Ethernet, Token Ring, FDDI Point-to-point serial links: Point-to-point Protocol (PPP), High-Level Data Link Control (HDLC) Point-to-point subinterface: Frame Relay, ATM Multipoint circuits with bandwidth greater than T1: Switched Multimegabit Data Service (SMDS), Frame Relay, ATM, ISDN PRI Hellos sent once every 60 seconds on the following links: Multipoint circuits with bandwidth less than or equal to T1: ISDN BRI, Frame Relay, SMDS, ATM, and X.25 Hold time by default is three times the hello time EIGRP Neighbors Initial Route Discovery EIGRP Metric EIGRP Metric Calculation By default,