1-31Normally, 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 thenumber of the AS where the PE resides. Therefore, the route updates that the PE receives from the CEalso include the number of the AS where the PE resides. This causes the PE unable to receive the routeupdates. In this case, routing loops must be allowed.2) On a CEFollow these steps to configure EBGP between PE and CE on a CE:To do… Use the command… RemarksEnter system view system-view —Enter BGP view bgp as-number —Configure the PE as the peerpeer { group-name |ip-address } as-numberas-numberRequiredConfigure the routeadvertisement behaviorimport-route protocol[ process-id ] [ med med-value |route-policyroute-policy-name ] *OptionalA CE needs to advertise itsroutes to the connected PE sothat the PE can advertise themto 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 detailedinformation, 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 andBGP Commands in the IP Routing Volume. This chapter does not differentiate between peer andpeer group.Configuring Route Advertisement Between PEsFollow these steps to configure route advertisement between PEs:To do… Use the command… RemarksEnter system view system-view —Enter BGP view bgp as-number RequiredConfigure the remote PE as thepeerpeer { group-name |ip-address } as-numberas-numberRequired
