Practical BGP

Peer Groups

Virtually every BGP implementation groups peers based on common outbound policies; Cisco IOS Software calls these groups of neighbors peer groups. Why do implementations group peers based on outbound policy toward the peers rather than in some other way? For the network administrator, this grouping can simplify configuration, allowing policies from a common group to be inherited by a number of neighbors rather than configuring each one independantly. Figure 5.1 illustrates, with a configuration from Cisco IOS Software following for router G, using peer groups to group eBGP peers with common outbound filtering policies.

Figure 5.1. BGP peer groups.

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In this example, the configuration isn't simplified by the use ...