OSPF can be used to exchange routes between CE routers and PE routers. In this situation, OSPF must be enabled on the CE router with a local area and enabled on the interface that is connected to the interface of the PE that is associated with the VRF that the user wants to advertise OSPF routes on. On the PE router, the VRF must be enabled in BGP to redistribute OSPF routes, and OSPF must be enabled for the VRF and configured to redistribute routes from BGP-VPNv4. The diagram below provides an example of a network where OSPF is used to exchange routes between CE routers and PE routers.
To configure OSPF to exchange routes between PE routers and CE routers, the user must perform the configuration steps listed below.