In the L3VPN domain, as shown in Unicast L3VPN domain discovered by the MPLS Topology Server, the MPLS Topology Server discovers VPN objects for unicast L3VPNs, such as VPNs, VRFs, and RouteTargets. When MPLS-BGP cross-domain correlation is enabled, the MPLS Topology Server also discovers the BGP session (BGPSession) objects that are underlying the VPN objects.
As shown in Multicast L3VPN domain discovered by the MPLS Topology Server, the MPLS Topology Server also discovers VPN objects for multicast L3VPNs, such as MulticastVPNs, MulticastGroups, VRFs, and RouteTargets. For the sake of simplicity, no MulticastGroups are shown in the figure.
A VRF can be configured to transport unicast traffic, multicast traffic, or both. The MPLS Topology Server models (represents) a VRF that transports both unicast and multicast traffic as being part of a VPN and a MulticastVPN.