3com S7906E Manuel De Montage

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Configuring a BGP Confederation 
Configuring a BGP confederation is another way for reducing iBGP connections in an AS. 
A confederation contains sub ASs. In each sub AS, iBGP peers are fully meshed. Between sub ASs, 
eBGP connections are established. 
If routers not compliant with RFC 3065 exist in the confederation, you can use the confederation 
nonstandard command to make the local router compatible with these routers. 
Configure a BGP confederation 
After you split an AS into multiple sub ASs, you can configure a router in a sub AS in the following way: 
1)  Enable BGP and specify the AS number of the router. 
2)  Specify the confederation ID. From an outsider’s perspective, the sub ASs of the confederation is a 
single AS, which is identified by the confederation ID.  
3)  If the router needs to establish eBGP connections to other sub ASs, you need to specify the 
peering sub ASs in the confederation. 
A confederation contains 32 sub ASs at most. The AS number of a sub AS is effective only in the 
confederation. 
Follow these steps to configure a BGP confederation: 
To do… 
Use the command… 
Remarks 
Enter system view 
system-view 
— 
Enter BGP view 
bgp as-number 
— 
Configure a confederation ID 
confederation id as-number
Required 
Not configured by 
default. 
Specify peering sub ASs in the 
confederation 
confederation peer-as 
as-number-list 
Required 
Not configured by 
default. 
 
Configure confederation compatibility 
If some other routers in the confederation do not comply with RFC 3065, you need to enable 
confederation compatibility to allow the router to work with those routers.  
To do… 
Use the command… 
Remarks 
Enter system view 
system-view 
— 
Enter BGP view 
bgp as-number 
— 
Enable compatibility with routers not 
compliant with RFC 3065 in the 
confederation  
confederation nonstandard
Optional 
Not enabled by default
 
Configuring BGP GR 
Perform the following configuration on the GR Restarter and GR Helper respectively.