cisco

17. EGP Topology Issues Continue.. To Prevent Routing Loops, Only Core Gateways Can Send information Learned from One AS to Another AS

19. EGP Message Types

22. Example 1-1 debug ip egp transactions Command Output Displays EGP State Transitions

24. Example 1-2 debug ip egp transactions Command Output Displays Two-Way Handshake Success and EGP State Transitions

26. Example 1-3 The Neighbor at 192.168.16.2 Has Stopped Responding. The Interval Between Each of the Unacknowledged EGP Messages Is 60 Seconds

27. Example 1-3. Continue..

29. Example 1-5 EGP Neighbors Poll Each Other Periodically for Network Reachability Updates

30. Example 1-5 Continue..

32. Figure 1-3 illustrates the concept of indirect EGP neighbors. One router, Moe, is a core gateway and is peered with three other gateways.

34. Example 1-6 shows the routing table of Shemp and the route entries resulting from the Update in Example 1-5.

39. Case Study: An EGP Stub Gateway Figure 1-10 shows an EGP stub gateway in AS 65502, connected to a core gateway in AS 65501. The IGP of the stub AS is RIP.

48. Figure 1-11. Core Router Stan Must Peer with Both Remote Neighbor Buster and Local Neighbor Ollie

52. Figure 1-12. Spanky and Buckwheat Must Peer Only with Stan, Whereas Alfalfa Must Peer Only with Ollie

56. Figure 1-13. EGP Indirect Neighbors

58. Example 1-18 shows the core gateway's indirect neighbors recorded as Third Party.

59. Example 1-19 Routing Table Displays Next-Hop Routes to Indirect Neighbors

62. Example 1-21 192.168.20.1 Is Reachable as a Result of the Default Route