3com 3031 Instruccion De Instalación

As route reflector is imported, it is possible that path looping will be generated in 
AS. Path update packets already left the cluster may attempt to return to the 
cluster. The conventional AS path method can’t detect the internal AS looping, 
because the path update packet has not left AS. Upon configuring route reflector, 
BGP provides the following measures to avoid internal AS looping:

1 Configuring the Originator_ID of the route reflector

If the Originator_ID is wrongly configured, the update packet will be returned to 
the originator, and the originator will discard it.

The parameter is not necessarily configured, and it will automatically function 
upon enabling BGP.

2 Configuring the Cluster_ID of the route reflector

Confederation provides another solution to handle the booming IBGP network 
connections inside an AS. It divides an AS into multiple sub-ASs, with the IBGP 
peers inside each sub-AS fully-connected and connecting to other sub-ASs in the 
confederation.

The shortcomings of confederation lie in: it is required that the router be 
reconfigured upon switching from non-confederation to confederation solution, 
and that the logic topology be basically changed. Furthermore, the path selected 
via confederation may not be the best path if there is no manually-set BGP policy.

In the sight of the BGP speakers that are not included in the confederation, 
multiple sub-ASs that belong to the same confederation are a whole. The external 
network does not need to know the status of internal sub-ASs, and the 
confederation ID is the AS number identifying the confederation as a whole.

Perform the following configurations in BGP view.

By default, the confederation ID is not configured.

The configured confederation ID cannot be the same as the existing AS number of 
a peer or a peer group.

Configure confederation ID first, and then configure the sub-AS belonging to the 
confederation. One confederation includes up to 32 sub-ASs. The as-number used 

Cancel the Cluster ID of the 
route reflector

Table 658   Configuring the cluster ID of the route reflector

Table 659   Configuring confederation ID

Configure confederation ID

Cancel confederation ID