Controlling the Advertisement of BGP Routes
Context
There are usually a large number of routes in a BGP routing table. Transmitting a great deal of routing information brings a heavy load to devices. Routes to be advertised need to be controlled to address this problem. You can configure devices to advertise only routes that these devices want to advertise or routes that their peers require. Multiple routes to the same destination may exist and traverse different ASs. Routes to be advertised need to be filtered in order to direct routes to specific ASs.