To allow OSPF route exchange between a PE router and its associated CE router, OSPF must be enabled on the PE‘s interface that is associated with the VRF and connected to the PE router. To configure OSPF on the interface of the PE 1 router that is associated with VRF VPN1 in OSPF for Route Exchange to CE 1, enter the following commands.
device(config)# interface ethernet 0/1
device(config-if-e10000-0/1)# vrf forwarding VPN1
device(config-if-e10000-0/1)# ip address 10.33.33.3/24
device(config-if-e10000-0/1)# ip ospf area 1