200
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 availability, as shown in Figure 57. The configured route reflectors must have
the same Cluster_ID to avoid routing loops.
Figure 57 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 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.
• 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. As shown in Figure 58,
intra-confederation EBGP connections are established between sub-ASs in AS 200.
Figure 58 Confederation network diagram
A non-confederation BGP speaker does not need to know sub-ASs in the confederation. It
considers the confederation as one AS, and the confederation ID as the AS number. In the
above figure, AS 200 is the confederation ID.
Route reflector1 Route reflector2
Client Client
Client
IBGP IBGP
IBGP
Cluster
IBGP
AS 65000
AS 100
EBGP
IBGP
IBGP
IBGP
EBGP
EBGP
AS 65002
AS 65003
AS 65004
AS 200
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