injecting default from one PE to another PE for a vrf?

Unanswered Question
Oct 5th, 2007

We are using vrf-lite which means no MPLS switching, only VRFs. we have a hub PE where we had VRF internet and VRF intranet. we would like other PEs to have a default to this hub in the intranet VRF, so all the internet traffic will go through this hub PE for internet traffic.

What I did is: two VRFs -internet and intranet in the hub PE, mutual import the route-target of the other.

For CE directly connected to the hub PE, I use the OSP default-information originate alway to inject a default to CE.

For spoke PE, I would like it to have a default to hub PE in the vrf intranet. Currently I am using iBGP neighbor spokeIP default-originate in the hub PE for this purpose, is this the right way to do it?

For CE connected to spoke PE, I also use ospf default-information originate alway to inject a default from PE to CE.

I have this problem too.
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swaroop.potdar Fri, 10/05/2007 - 09:18

Yes it would be right to originate default form your Hub PE to spoke PE on the IPV4 VRF address family.

But what i cna gather form your explnation is there is also another PE which is spoke PE, in this case how will the traffic be switched without MPLS. And if you have VPNV4 peering between HUB and SPOKE PE you cannot call it VRF-lite.



sding2006 Fri, 10/05/2007 - 09:53

Here is what I did in the lab






the HUB PE is having internet and intranet vrfs.

SPOKE1 and SPOKE2 is only having intranet vrf.

VL198 and VL199 are all with ip vrf forwarding intranet. then the ospf vrf intranet will have neighbor relationship among HUB and SPOKE[12], I then don't need the vpnv4 address-family.

You reminded me that this is not BGP/MPLS intended to do. I will also try not to put vl199 and vl198 in ip vrf forward intranet, and have vpnv4 address-family configured between both HUB and SPOKE PEs. Do I have to have MPLS switching to use vpnv4?


swaroop.potdar Fri, 10/05/2007 - 11:05

Looking at your topology makes things more clear. As per your topo and configuration(is of vrf on the HUB and SPOKE PE interconnect, you dont need label switching. It would be plain routed.

You can continue with the original plan of originating the default from the HUB PE. That should work.



sding2006 Mon, 10/08/2007 - 07:32

Actually, in my case, the iBGP between HUB and SPOKE is not needed. ospf is sufficient.

default-information originate alway will inject a default from hub to spoke.

swaroop.potdar Mon, 10/08/2007 - 08:49

Since it would be plain routing within a given vrf you can use the protocol which you deem to be fit for your topology. (From BGP or OSPF).

As it would not be possible to recommend the protocol with the information at hand.




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