Problem: Internal BGP Neighbors Not Coming Up

IBGP can experience issues similar to EBGP in neighbor relationship. IBGP is an important piece of overall BGP-running networks. Chapter 14 discusses the importance and usage of IBGP. This section addresses some commonly seen issues exclusive to IBGP neighbor relationship problems. The causes of this problem are identical to the previous problem of nondirectly connected external BGP neighbors not coming up:

• The route to the nondirectly connected IBGP neighbor address is missing.

• The update-source interface command is missing in BGP configuration.

You can use the same troubleshooting and configuration techniques as those used for the EBGP problem.