Notable Replies

  1. Hi Alfredo,

    Are your London and Italy sites only advertising their own prefixes?

    If you want your users from CE2 to be able to reach London in case CE-1 is down then you should advertise the prefixes from London from OSPF into BGP on Italy so that CE3 can learn them. You could use conditional advertising or use some of the BGP attributes so that this path is not preferred as long as CE-1 is up and running.


  2. Hi Rene,

    I tried to redistributed the route into the OSPF in CE1 router, and the PE1 did received the route as E2 route. But the other PE2 not received the VPNV4 route from PE1 and also can not advertised it to CE2. Any idea how to fix this?


  3. Hi Davis,

    There’s a lot of things that could be wrong. Here’s a simple checklist you can use:

    Here’s what you should check and in what order:

    1. Make sure your PE/P routers have established LDP neighbor adjacencies using loopback interfaces as the transport addresses.

    2. Make sure the VRF is created on both PE routers.

    3. Make sure you use the correct RD for each VRF.

    4. Make sure you have the correct import/export route-targets.

    5. Check if you see routes in the VRF routing table on the PE routers.

    6. Check if you have an IBGP neighbor adjacency between the PE routers for the VPN address-family.

    7. Make sure that extended communities are sent between the PE routers.

    8. Make sure you see VPN routes on each PE router.

    9. Make sure you see routes on both CE routers.

    These are basically all the things you should check.


  4. On CE routers why can’t I see MPLS label in traceroute result?

    Type escape sequence to abort.
    Tracing the route to
      1 8 msec 16 msec 20 msec
      2 36 msec 52 msec 64 msec
      3 28 msec 24 msec 40 msec
      4 64 msec 68 msec 64 msec
  5. Hello Andrew

    The OSPF domain ID is used as a BGP Extended Community Attribute. It’s primary use is indeed with MPLS VPNs. I am not familiar with any other uses of this particular attribute.

    I hope this has been helpful!


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