Sham-link inside a TE Tunnel

Is there any reason why a sham-link does not seem to do its thing when goes inside a TE tunnel?

Comments

  • What do you mean by saying that sham-link is not doing its job? Is it up? 

    I don't remember any issues with the sham-link and MPLS TE configured on the same network.

    Can you show PEs configs (relevant parts only)

    Cheers,

    Seba












  • I don't recall any issues off the top of my head with sham links
    and TE.  Is your TE properly configured?

     

    Scott

     

     

    From: [email protected]
    [mailto:[email protected]] On Behalf Of Ricardo Martins

    Sent: Monday, March 23, 2009 10:43 AM

    To: [email protected]

    Subject: [CCIE SP] Sham-link inside a TE Tunnel

     

    Is there any reason why a sham-link does not seem to do its thing when goes
    inside a TE tunnel?







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  • I have a feeling this one aint a BUG but my fault.

    SITEA--------R1---------R2--------R3----------R4---------SITEA

     

    I have a TE from R1 to R3, then from R3 to R4 just normal LDP.

    Then a sham-link from R1 to R4.

    Now, the auto announce feature on the R1 TE tunnel is making R1 to route tru the TE tunnel to get to R3 Loop, the network between R3 and R4 and R4 Loop.

    I CANT PING FROM SITE A to SITE A.

    Is it a problem to learn R4 Loopback through the TE tunnel??

     

    In conlusion, my workaround is

    In R1:

    disable auto announce and just a static route to R3 Loop

    or

    Auto announce and a static route to R4 loop out of the tunnel,so I no longer learn R4 Loop tru the tunnel

     

  • Try to enable LDP on the TE tunnel

    Rin

  • That's it, as MPLS TE Tail router is P not PE you have to enable "mpls ip" on the Tunnel interface!

    After this, configuration with auto-announce should be working fine

    Cheers,

    Seba

  • The problem is, as other said, a broken MPLS LSP.

    Why? because you are sending traffic using the TE and no mpls labels are learnt through it.

    Solution?
    1. Use mpls ip on the tunnel interface AND the mpls ldp discovery targeted-hello accept on the tail router! after that MPLS labels will be sent using the TE tunnel and sham link will work.
    2. Use static routing or PBR instead of autoroute announce (you cant use that on the LAB)

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