VRF route import extended community

VRF route import is an IP address-specific extended community, of an extended type, and is transitive across AS boundaries (RFC 4360, BGP Extended Communities Attribute).

To support MVPN, in addition to the import/export route target extended communities used by the unicast routing, each VRF on a PE must have an import route target extended community that controls imports of C-multicast routes into a particular VRF.

The c-multicast import RT uniquely identifies a VRF, and is constructed as follows:

A PE that has sites of a specific MVPN connected to it communicates the value of the c-multicast import RT associated with the VRF of that MVPN on the PE to all other PEs that have sites of that MVPN. To accomplish this, a PE that originates a (unicast) route to VPN-IP addresses includes in the BGP updates message that carries this route the VRF route import extended community that has the value of the c-multicast import RT of the VRF associated with the route, except if it is known a priori that none of these addresses acts as multicast sources and, or RP, in which case the (unicast) route need not carry the VRF Route Import extended community.

All c-multicast routes with the c-multicast import RT specific to the VRF must be accepted. In this release, vrf-import and vrf-target policies do not apply to C-multicast routes.

The decision flow path is shown below.

 if (route-type == c-mcast-route)

  if (route_target_list includes C-multicast_Import_RT){

   else

    drop;

  else

  Run vrf_import and, or vrf-target;