confederation
In BGP, an autonomous system that has been subdivided into smaller autonomous systems called confederation member autonomous systems. (CMASs). A confederation appears like a single autonomous system to other autonomous systems and is recognized only by other confederation members. Subdivision of an autonomous system into a confederation changes the peer relationships of confederation members in different CMASs from internal to external. Use of confederations in an autonomous system requires that all routers in the autonomous system belong to a CMAS; however, the policies used by BGP peers can change across confederation boundaries.
Confederations are one method for avoiding the overhead of having all peers within an autonomous system fully communicate to---be fully meshed with---each other. Route reflection clusters provide an easier method, but require the use of identical policies on all peers within the autonomous system. See also route reflection.