To configure BGP sessions between peering networks, you must configure point-to-point sessions between the external peers of the networks. Additionally, you must configure BGP internally to provide a means by which BGP route advertisements can be forwarded throughout the network. Because of the full mesh requirement of IBGP, you must configure individual peering sessions between all internal nodes of the network—unless you use route reflectors or confederations.
Figure 79 shows a typical network with external and internal peer sessions. In the sample network, the Services Router in AS 17 is fully meshed with its internal peers in the group internal-peers, which have IP addresses starting at 192.168.6.4.
Figure 79: Typical Network with EBGP External Sessions and IBGP Internal Sessions
To configure IBGP in the network shown in Figure 79:
Table 138: Configuring IBGP Peering Sessions