Establishing Neighbors

Before you can actually exchange any routing information in BGP, you have to establish peering relationships with other BGP speakers. Lack of IP connectivity and neighbor setting mismatches are common reasons for a BGP peering session to fail.

No IP Connectivity

Perhaps the most common, and easiest to troubleshoot, problems involved in a failure to bring up a BGP session are simple lack of IP connectivity and mismatched endpoints. We'll use Figure 8.1 as an example.

Figure 8.1. IP connectivity between BGP peers.

We'll take the simplest case first, two routers not building a peering session. The first step is to examine the ...

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