route reflection

In BGP, a method for maintaining path and attribute information across an autonomous system, while avoiding the overhead of having all peers within an autonomous system fully communicate to---be fully meshed with---each other. To reduce the number of links, all internal peers are divided into clusters, each of which has one or more route reflectors. A route received by a route reflector from an internal peer is transmitted to its clients, which are the other peers in the cluster that are not route reflectors. Route reflection requires that all internal peers use identical policies.

Confederations are another way to avoid configuring a fully meshed set of peers in a single autonomous system. In contrast to route reflection clusters, confederations require all routers in the autonomous system to operate as confederation members. However, confederations provide a finer control of routing within the autonomous system by allowing for policy changes across confederation boundaries. See also cluster; cluster ID; confederation; route reflector.