Configuring BGP AS Number Substitution in L3VPN.

Configuration Prerequisites

Before configuring BGP AS number substitution, complete these tasks:

• Configuring basic MPLS L3VPN
• Configuring CEs at different sites to have the same AS number

Configuration Procedure

When CEs at different sites have the same AS number, you need to configure the BGP AS number substitution function to avoid route loss.

With the BGP AS number substitution function, when a PE advertises a route to a CE of the specified peer, if an AS number identical to that of the CE exist in the AS_PATH of the route, it will be replaced with that of the PE before the route is advertised.

Follow these steps to configure the BGP AS number substitution function:

Note:

For information about the peer { ip-address | group-name } substitute-as command, refer to BGP Commands in the IP Routing Volume.

Displaying and Maintaining MPLS L3VPN

Resetting BGP Connections

When BGP configuration changes, you can use the soft reset function or reset BGP connections to make new configurations take effect. Soft reset requires that BGP peers have route refreshment capability (supporting Route-Refresh messages).

Displaying and Maintaining MPLS L3VPN

Note:

For commands to display information about a routing table, refer to IP Routing Table Commands in the IP Routing Volume.