Hi,
I have an issue running MPLS on an OSPF topology made of Cisco 6509 / Sup32.
I have 2 routers 6509, linked with a gigabits fiber set up as a trunk with few vlan passing through.
I also have on RouterA and RouterB few VRFs.
I want those VRF to exchange their routes between themself using the OSPF already set up between the two devices.
I have added the "tag-switching ip" on the layer2 fiber interface on both side of the link. I also set it up on the layer 3 vlan interface on both side.
OSPF is running on both routers and everything is ok for the standart routing table (the global one), but it does not seems to work for the VRF.
I guess the problem comes from the link between the 2 routers which is not a full "MPLS link". The fact that the link is a trunk divided into vlan makes the MPLS communication down ?
Any idea ?
Thanks a lot for your answer.
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Hi there,
Thanks you for your answer.
Actually, I knew I could use BGP but I would like to avoid it, if possible. The main reason is that OSPF is already running on the 2 device and BGP is not, so it would be some kind of waist of memory on the device to run 2 routing protocol. No ?
Does anybody tried MPLS over OSPF ?
It sounds like a novel idea, but I''m not sure it is possible. The VRF information (vrf routing table plus route-distinguisher information) is transmitted in the extended community settings of BGP, and I do not think that OSPF can transport this kind of information. Maybe IS-IS can (with it's TLV structure), but then BGP would be much easier to set-up, in my opinion. To do this via OSPF would require a change in the OSPF standard, and I do not think that very likely. But I'll see if I can dig up something on the matter.
You can, of course, keep OSPF as IGP, and only run eBGP. This is how I have implemented VPN's in my current network (worked well for a phased-in approach).
That's an idea, but how do I use the link between the 2 routers since I would like to use mpls label on it and not to configure a VLAN for each VRF between ?
I mean, if I do something like that on router A :
router ospf 10 vrf XXX
netmork a.b.c.d area 10
And this on router B :
router ospf 10 vrf XXX
netmork e.f.g.h area 10
How does the 2 area will be communicating if I do not set up a VLAN with layer 3 address between them ?
Router A and B will have to be directly connected via a L3 interface for above to work so that the routers can establish an adjacency. You will also need to have an OSPF process (and a L3 link) for every VRF (and the global routing table) you want to synchronise.
You could implement a separate OSPF process on any intermediary routers (between A and B), but if it does not support VRF's, you will just end up combining the routing tables of the VRF's and negate any benefit of implementing VRF's in the first place.
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by: Otto_NPosted on 2009-11-06 at 05:21:35ID: 25758804
I do not know if I understand your set-up or goals correctly, so please tell me of I make incorrect assumptions.
The way I understand it, VRF's can only exchange routing info if it is syncronising via multi-ptotocol BGP. So you will have to configure BGP as well. I attach a sample config that might point you in the right direction.
As I said, let me know if I completely under-estimated your problem.
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