188
Figure 54
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 55
,
intra-confederation EBGP connections are established between sub-ASs in AS 200.
Figure 55
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.
Confederation has a deficiency. When you change an AS into a confederation, you must
reconfigure the routers, and the topology will be changed.
