The Virtual Routing and Forwarding (VRF) Instance

The VPN allows an enterprise to maintain data privacy when transmitted over a public network. The VRF provides a separate routing domain within the public PE router for that enterprise by partitioning the router into segregated routing domains for the forwarding of packets. A VRF dedicated to a L3 VPN is a requirement, but the naming of that VRF has descriptive significance only. Virtual Routing and Forwarding (VRF) Configuration for a detailed discussion on how to create and configure a VRF.

Once the VRF is created, within that VRF:

• Configure any interfaces required to attach to the CE router.
• Configure the IGP instance, such as OSPF, to communicate with the attached CE router.
• Configure the RD for purposes of uniquely identifying the IP name-space and also required to handle overlapping IP addresses (See The Route Distinguisher (RD)).
• Configure route targets that define policies for importing and exporting VPN addresses for this VRF (See The Route Target).
• Optionally, modify the MPLS label mode to allocate a unique MPLS label for each prefix route in the routing table (Defaults to one MPLS label per VRF). See MPLS Label Mode.