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OSPF Failover issues

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  • OSPF Failover issues

    I have six routers and one of them is a Catalyst switch, all of them cisco running IOS 12.x.

    For a long time, we have used a single router as a gateway to the internet, with a second router behind it doing a site to site VPN to India. This has been serving us well, but we wanted a bigger pipe to India as there were some massive file transfers.

    We have: A core switch (Catalyst 6500 series) running routing, OSPF, and several vlans to segment traffic.(CoreSW)

    The two routers mentioned earlier, one a ISP-facing router for the t1, the second doing a VPN tunnel to India.(ISP)(VPN01)(VPN02)

    A router on a MPLS circuit for dedicated traffic to India, as well as one on the far end in India.(MPLS1, MPLS2)

    Now, I added the MPLS circuit, configured the routers with OSPF, and set the CoreSW to weight the MPLS circuit as a preferred circuit and everything works! OSPF figures out the proper route and routes all traffic to and from India over the MPLS circuit.

    So far so good. However, with OSPF, I SHOULD be able to unplug the MPLS router and the CoreSW should be able to automatically change the route over the VPN. However, instead it routes all traffic out to the ISP, skipping the VPN tunnel.

    Now to trouble-shoot this issue, I have made sure that OSPF is working on all connections, the VPN is a GRE tunnel passing OSPF, and the two VPN routers see each other as neighbors.

    My question is WHY would traffic route out to the internet instead of over the VPN, when I've not changed anything on the VPN other than weighing it as 'heavier' than the MPLS circuit to make the MPLS circuit primary?

    ASCII Summary:

    ISP ---(GRE IPSec Tunnel) --- VPN02 --India Network
    | \ |
    | \ |
    VPN01 MPLS02
    | |
    | |
    CoreSW ----------------------------------- MPLS01
    | \
    Internal VLANs

    Let me know if I need to clarify anything.
    Last edited by shoffmann; 12th March 2009, 23:09. Reason: ASCII not working properly! (Excluding spaces when I post)