CCNP Routing and Switching ROUTE 300-101 Official Cert Guide

Configuring iBGP

The most basic iBGP configuration differs only slightly compared to eBGP configuration. The configuration does not explicitly identify an eBGP versus an iBGP peer. Instead, for iBGP, the neighbor’s ASN listed on the neighbor neighbor-ip remote-as neighbor-asn command lists the same ASN as the local router’s router bgp command. eBGP neighbor remote-as commands list a different ASN.

When two iBGP peers share a common physical link, such as E1 and E2 in Figure 14-2, the iBGP configuration simply requires a single neighbor remote-as command on each router. Example 14-1 shows the BGP configuration on both Router E1 and E2 with this single neighbor command highlighted. The rest of the configuration lists the commands used to configure ...