HPE 5800 Series Configuration Manual page 187

Using route reflectors can solve this issue. In an AS, a router acts as a route reflector, and other
routers act as clients connecting to the route reflector. The route reflector forwards the routing
information received from a client to other clients. In this way, all clients can receive routing
information from one another without establishing BGP sessions.
A router that is neither a route reflector nor a client is a non-client, which, as shown in
must establish BGP sessions to the route reflector and other non-clients.
Figure 63 Network diagram for a route reflector
The route reflector and clients form a cluster. Typically a cluster has one route reflector. The ID
of the route reflector is the Cluster_ID. You can configure more than one route reflector in a
cluster to improve network reliability and prevent a single point of failure, as shown in
The configured route reflectors must have the same Cluster_ID in order to avoid routing loops.
Figure 64 Network diagram for route reflectors
When the BGP routers in an AS are fully meshed, route reflection is unnecessary because it
consumes more bandwidth resources. You can use related commands to disable route
reflection instead of modifying network configuration or changing network topology.
After route reflection is disabled between clients, routes can still be reflected between a client
and a non-client.
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Confederation
Confederation is another method to manage growing IBGP connections in an AS. It splits an AS
into multiple sub-ASs. In each sub-AS, IBGP peers are fully meshed, and as shown in
intra-confederation EBGP connections are established between sub-ASs.
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Figure 63,
Figure 64.
Figure 65,