CCIE Practical Studies: Security (CCIE Self-Study)

Troubleshooting EIGRP

When you are troubleshooting EIGRP, it helps to think about the process EIGRP uses in its operation:

Step 1.	EIGRP neighbor adjacencies must be established.
Step 2.	Each router with EIGRP enabled—the EIGRP speaker—must build its topological database.
Step 3.	The feasible distance entries in a given router's topology table must be greater than the directly connected EIGRP neighbor's advertised metric.
Step 4.	The optimal topology table entries are used in the IP routing table.

If you need to reinitialize the EIGRP routing process, you can enter the following command:

R1#clear ip eigrp neighbors [ip-address | interface]

Example 9-16 shows the message you receive when clearing an EIGRP neighbor.

Example 9-16. clear ip eigrp ...