Routing Policy Application in Inter-AS VPN Option C
On the network shown in the figure below, CE1 and CE2 communicate with each other through inter-AS VPN Option C.
To establish an inter-AS label switched path (LSP) between PE1 and PE2, route-policies need to be configured for autonomous system boundary routers (ASBRs).
- When an ASBR advertises the routes received from a PE in the same AS to the peer ASBR, the ASBR allocates MPLS labels to the routes using a route-policy.
- When an ASBR advertises labeled IPv4 routes to a PE in the same AS, the ASBR reallocates MPLS labels to the routes using another route-policy.
In addition, to control route transmission between different VPN instances on a PE, configure a route-policy for the PE and configure the route-policy as an import or export policy for the VPN instances.
