3com S7906E 安装指导

 

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Normally, BGP detects routing loops by AS number. In the hub and spoke networking scheme, however, 

with EBGP running between PE and CE, the routing information the PE advertises to a CE carries the 

number of the AS where the PE resides. Therefore, the route updates that the PE receives from the CE 

also include the number of the AS where the PE resides. This causes the PE unable to receive the route 

updates. In this case, routing loops must be allowed. 

 

2)  On a CE 

Follow these steps to configure EBGP between PE and CE on a CE: 

Enter system view 

— 

Enter BGP view 

bgp as-number 

— 

Configure the PE as the peer 

peer { group-name | 
ip-address } as-number 
as-number 

Required 

Configure the route 
advertisement behavior 

import-route protocol 
[ process-id ] [ med med-value | 
route-policy 
route-policy-name ] * 

Optional 

A CE needs to advertise its 
routes to the connected PE so 
that the PE can advertise them 
to the peer CE. 

 

z 

Exchange of BGP routes for a VPN instance is the same as that of ordinary BGP routes. 

z 

The configuration task in BGP instance view is the same as that in BGP view. For detailed 

information, refer to BGP Configuration and BGP Commands in the IP Routing Volume. 

z 

For information about BGP peer and peer group configuration, refer to BGP Configuration and 

BGP Commands in the IP Routing Volume. This chapter does not differentiate between peer and 

peer group. 

 

Follow these steps to configure route advertisement between PEs: 

Enter system view 

— 

Enter BGP view 

bgp as-number 

Required 

Configure the remote PE as the 
peer 

peer { group-name | 
ip-address } as-number 
as-number 

Required