[c-nsp] Inter-VRF OSPF Redistribution

Chris Mason chris at noodles.org.uk
Fri Feb 19 07:15:14 EST 2010


Does anyone know whether it is possible to redistribute routes between 
two different OSPF processes when they are associated with different VRFs?

I have the following setup on some routers running 12.4(15)T:

    +-----+ [VRF]              +----+
    | CPE +-[0/0]--------[0/0]-+ S1 |
    +--+--+   +----+

On the CPE, interface 0/0 is contained within a vrf "VPN" and the 
interface 0/1 is within the global table. I could place both interfaces 
within different VRFs and use redistribution, but I need to maintain 0/1 
within the global table and routing table seperation between them.

Traffic from S1 needs to reach the LAN attached to 0/1 on the CPE. I 
could use route leaking to global using a static for traffic from S1 to 
the CPE LAN, but the problem arises with the return traffic. I don't 
know the source address of the traffic, but it is advertised into OSPF 
from S1 (S1 is a roaming host which can connect to different CPE devices 
and depending on what S1 connects depends on the source address).

To identify the source address (/32) I advertise the source from S1 with 
an arbituary tag in a Type 5 LSA. I then need a way to redistribute that 
route into the global table for return traffic.

I was hoping to use something like this, but it is rejected when I 
attempt to do inter-vrf redistribution:


router ospf 10
  redistribute ospf 20 vrf VPN subnets route-map OSPF20_to_OSPF10

route-map OSPF20_to_OSPF10
  match tag <TAG>

router ospf 20 vrf VPN
  capability vrf-lite
  network area 0

I get the following error:

%OSPF process 20 is attached to VRF VPN

Is there anyway to get around this?


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