VRF and RouteTarget

The MPLS Topology Server relates VRFs and RouteTargets through the Imports/ImportedBy and Exports/ExportedBy relationship sets, and then discovers which interfaces are associated with each VRF. RouteTargets are used to identify peering relationships between VRFs and to identify different Layer 3 VPN types (full-mesh, hub-and-spoke).

Some computed relationships for VRFs are:

• VRF relationship SendsRoutesTo

  Points from a VRF to all other VRFs that import a RouteTarget that this VRF exports. The other VRFs get route advertisements from this VRF by having a route target on their import list that matches a route target on this VRF’s export list.

• VRF relationship ReceivesRoutesFrom

  Points from a VRF to all other VRFs that export a RouteTarget that this VRF imports. The other VRFs advertise routes to this VRF by having a route target on their export list that matches a route target on this VRF’s import list.

• VRF relationship VPNPeer

  Points from a VRF to all other VRFs that are related to this VRF by both SendsRoutesTo and ReceivesRoutesFrom.

• VRF relationship CEs

  Points from a VRF to the CE or multi-VRF CE device attached to this VRF.

• VRF relationship HostedBy

  Relates a VRF to the PE device that is hosting this VRF.