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PowerConnect B-Series FCX Configuration Guide 1021
53-1002266-01
Optional configuration tasks
30
If you need to disable route reflection between clients, enter the following command. When the
feature is disabled, route reflection does not occur between clients but reflection does still occur
between clients and non-clients.
PowerConnect(config-bgp-router)#no client-to-client-reflection
Enter the following command to re-enable the feature.
PowerConnect(config-bgp-router)#client-to-client-reflection
Syntax: [no] client-to-client-reflection
Configuration notes
A confederation is a BGP4 Autonomous System (AS) that has been subdivided into multiple,
smaller autonomous systems. Subdividing an AS into smaller autonomous systems simplifies
administration and reduces BGP-related traffic, thus reducing the complexity of the Interior Border
Gateway Protocol (IBGP) mesh among the BGP routers in the AS.
The Dell implementation of this feature is based on RFC 3065.
Normally, all BGP routers within an AS must be fully meshed, so that each BGP router has
interfaces to all the other BGP routers within the AS. This is feasible in smaller autonomous
systems but becomes unmanageable in autonomous systems containing many BGP routers.
When you configure BGP routers into a confederation, all the routers within a sub-AS (a subdivision
of the AS) use IBGP and must be fully meshed. However, routers use EBGP to communicate
between different sub-autonomous systems.
NOTE
Another method for reducing the complexity of an IBGP mesh is to use route reflection. However, if
you want to run different Interior Gateway Protocols (IGPs) within an AS, configure a confederation.
You can run a separate IGP within each sub-AS.
To configure a confederation, configure groups of BGP routers into sub-autonomous systems. A
sub-AS is simply an AS. The term “sub-AS” distinguishes autonomous systems within a
confederation from autonomous systems that are not in a confederation. For the viewpoint of
remote autonomous systems, the confederation ID is the AS ID. Remote autonomous systems do
not know that the AS represents multiple sub-autonomous systems with unique AS IDs.
NOTE
You can use any valid AS numbers for the sub-autonomous systems. If your AS is connected to the
Internet, Dell recommends that you use numbers from within the private AS range (64512 through
65535). These are private autonomous systems numbers and BGP4 routers do not propagate these
AS numbers to the Internet.
Figure 148 shows an example of a BGP4 confederation.