VRF lite with GRE

Mukarram Jah Raheel · ‎09-04-2009

Topology : A1 - X - Y -Z - A2

Note : this is pure IP network with no MPLS

Requirement: VRF lite is used on SP edge routers X and Y , therefore have diff routing tables for all customers(in this case only 1 customer with two sites C1 and C2).

how can i transport C1 routes to C2 through GRE ??? I dont want to use subinterfaces and multi routing process on routers....

Is there a way to transport customer routes ( between C1 and C2) using GRE tunnel between routers X and Y ....

Peter Paluch · ‎09-05-2009

Hi,

You have probably already discovered the way to do it but just in case:

The Tunnel interfaces are VRF-aware. There are two points to consider: first, in which VRF does the tunnel interface appear as an interface, and second, in which VRF should be used to look up the source and destination of the tunnel. The first point is determined by the usual "ip vrf forwarding" command, while the other is configured using the "tunnel vrf" statement.

Quoting from the IOS Interface and Hardware Component Command Reference:

The following example shows how to associate a VRF with a tunnel destination. The tunnel endpoint, 10.5.5.5 will be looked up in the blue VRF.

interface tunnel0

ip vrf forwarding green

ip address 10.3.3.3 255.255.255.0

tunnel source loop 0

tunnel destination 10.5.5.5

tunnel vrf blue

If you want to look up the source and destination IP addresses of the tunnel in the global routing table, simply omit the "tunnel vrf" command.

Best regards,

Peter