3.7.e [i] Route-reflector, cluster
a lot of theory, very little to do…
When the route reflector receives an advertised route, depending on the neighbor, it takes the following actions:
•A route from an external BGP speaker is advertised to all clients and nonclient peers.
•A route from a nonclient peer is advertised to all clients.
•A route from a client is advertised to all clients and nonclient peers. Hence, the clients need not be fully meshed.
An autonomous system can have multiple route reflectors. A route reflector treats other route reflectors just like other iBGP speakers. A route reflector can be configured to have other route reflectors in a client group or nonclient group. In a simple configuration, the backbone could be divided into many clusters. Each route reflector would be configured with other route reflectors as nonclient peers (thus, all the route reflectors will be fully meshed). The clients are configured to maintain iBGP sessions with only the route reflector in their cluster.