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IS-IS/LDP/MPLS is ready, but no push label

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  • 1.  IS-IS/LDP/MPLS is ready, but no push label

    Posted 07-12-2018 22:17
      |   view attached

    Hi All

     

    My router LAX enable IS-IS/LDP/MPLS with adjaceny TOK and SJC.

    I found LAX don't push label to any routes leanning from TOK. But SJC has.

     

    As checked, IS-IS/LDP/MPLS are all ready and don't get any issue.

    But the same prefix have different result when is shown both on  LAX/SJC as follow.

     

    LAX_RE1> show route 45.64.53.0/24                           

    inet.0: 699334 destinations, 1959811 routes (699333 active, 1 holddown, 3010 hidden)

    + = Active Route, - = Last Active, * = Both

    45.64.53.0/24      *[BGP/170] 00:14:46, localpref 120, from 172.54.128.2

                                     AS path: 38197 I, validation-state: unverified

                                     > to 10.31.100.26 via xe-7/3/1.0

     

    SJC_RE0> show route 45.64.53.0/24

    inet.0: 696527 destinations, 725972 routes (696524 active, 4 holddown, 9 hidden)

    + = Active Route, - = Last Active, * = Both

    45.64.53.0/24      *[BGP/170] 00:08:00, localpref 120, from 172.54.129.2

                                     AS path: 38197 I, validation-state: unverified

                                    > to 10.31.100.38 via et-11/1/5.0, Push 300336

     

    As follow is my infrastructure and as attachemnt is my configuration, do I miss anything or anyway to figure out this problem ?

    螢幕快照 2018-07-13 下午1.16.31.png

     


    #MPLS

    Attachment(s)

    rtf
    MPLS.rtf   6K 1 version


  • 2.  RE: IS-IS/LDP/MPLS is ready, but no push label

    Posted 07-12-2018 23:36

    Hello,

    I already answered this question in https://forums.juniper.net/t5/Routing/MPLS-don-t-push-label-to-BGP-route/m-p/329622#M18349

    In short - this is not  a problem but LDP default behaviour called PHP.

    TOK advertises own loopback with label 3 to  LAX.

    LAX advertises TOK's loopback to SJC with label 300336.

    Also, LAX advertises own loopback to both TOK and SJC with label 3.

    So, if You try to see an LAX' active route on TOK/SJC it should also show no label.

    HTH

    Thx

    Alex



  • 3.  RE: IS-IS/LDP/MPLS is ready, but no push label

    Posted 07-12-2018 23:50

    Hi 

     

    I will research this behavior of LDP PHP. 

    And I have one more question about how to show label 3 in LAX ?  Is it working normally on mpls fuction ?

     

    Thanks

    Cloud 



  • 4.  RE: IS-IS/LDP/MPLS is ready, but no push label
    Best Answer

    Posted 07-13-2018 10:28

    Hello,

     


    @Cloud wrote:

    Hi 

      

    And I have one more question about how to show label 3 in LAX ? 


     "show ldp database extensive" will display the LDP FECs with associated label values - advertised and received.

     


    @Cloud wrote:

      Is it working normally on mpls fuction ?

     

     


    Label 3 is purely MPLS control plane "function" and label 3 is never present in the actual data packet.

    So if You define "working" as "seen in LDP control plane printout above" then yes.

    HTH

    Thx

    Alex