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  1. Resident Underachiever EdTheLad's Avatar
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    #1

    Default MPLS TE Explicit Null

    I've seen by default in Cisco ios the tailend router advertises an explicit null label(0) to its upstream neighbor, the upstream router interprets this as an implicit null (3) even though it's an explicit null. I've read how to make this compliant you can configure the tailend router with the following command "mpls traffic-eng signalling advertise implicit-null", which means the tailend will now advertise the implicit null(3).

    As per rfc 3032, if a packet arrives with an explicit null label(0) and it's not the bottom of stack label, the packet will be discarded. So if ldp were running over the tunnel, and the tunnel was using the explicit null label, the packets would be dropped.

    What i want to do is send packets over a tunnel, (no ldp enabled over the tunnel) and preserve the qos markings. How do i make the router upstream from the tailend router send packets with the explicit null label rather than the implicit null label?
    Networking, sometimes i love it, mostly i hate it.Its all about the $$$$
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  2. Resident Underachiever EdTheLad's Avatar
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    #2
    Hidden command, which allows the penultimate router to process the received explicit null label.
    mpls traffic-eng signalling interpret explicit-null verbatim
    Last edited by EdTheLad; 09-19-2015 at 12:50 PM.
    Networking, sometimes i love it, mostly i hate it.Its all about the $$$$
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