H3C Technologies H3C S12500 Series Switches - Manual (Page 217)

201
Figure 80 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.
• 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
Figure 81 ,
intra-confederation EBGP connections are established between sub-ASs.
Figure 81 Confederation network diagram
A non-confederation BGP speaker is not required 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 your routers, and the topology will be changed.
AS 100
EBGP
IBGP
IBGP
IBGP
EBGP EBGP
AS 65002 AS 65003
AS 65004
AS 200