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Juniper documentation question

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  • 1.  Juniper documentation question

    Posted 06-19-2021 02:25

    I came across the following ;

    "Verify that the router LSA originated by the instance carries the sham link adjacency as an unnumbered point-to-point link. The link data for sham links is a number ranging from 0x80010000 through 0x8001ffff."   

    user@PE1> show ospf database instance red 
    
        OSPF database, Area 0.0.0.0
     Type       ID               Adv Rtr           Seq      Age  Opt  Cksum  Len 
    Router   192.0.2.1          192.0.2.1          0x80000009  1803  0x22 0x6ec7  72
    Router   192.0.2.5          192.0.2.5          0x80000007    70  0x22 0x2746  72
    Router  *198.51.100.2          198.51.100.2          0x80000006    55  0x22 0xda6b  60
    Router   198.51.100.4          198.51.100.4          0x80000005    63  0x22 0xb19   60
    Network  10.0.0.18        192.0.2.5          0x80000002    70  0x22 0x9a71  32
        OSPF AS SCOPE link state database
     Type       ID               Adv Rtr           Seq      Age  Opt  Cksum  Len 
    Extern   198.51.100.2          198.51.100.4          0x80000002    72  0xa2 0x343   36
    Extern  *198.51.100.4          198.51.100.2          0x80000002    71  0xa2 0xe263  36

    Based on the line above, which sequence number indicates the link data for sham links ?

    thanks !!



  • 2.  RE: Juniper documentation question

    Posted 08-06-2021 05:28
    To access the link-data you need to expand the Router LSA with the extensive option and verify the Link Data field within the LSA. Any unnumbered interface in OSPF is assigned an index value, this is what that paragraph is referring to in the documentation and not to the Sequence value or the ID of the LSA headers.

    Elvin


  • 3.  RE: Juniper documentation question

    Posted 08-06-2021 11:21
    thanks !!


  • 4.  RE: Juniper documentation question
    Best Answer

    Posted 08-07-2021 05:28
    Just for anyone who arrives here in the future, see the data field with the value of 128.1.0.0 dotted decimal which is equal to 0x80010000 hex when having a sham-link configured in Junos.

    root@r2# run show ospf database instance 1 extensive
    
        OSPF database, Area 0.0.0.0
     Type       ID               Adv Rtr           Seq      Age  Opt  Cksum  Len
    Router   100.100.100.1    100.100.100.1    0x80000002   312  0x22 0x55cf  36
      bits 0x1, link count 1
      id 100.100.100.2, data 128.1.0.0, Type PointToPoint (1) <<< ! Here
        Topology count: 0, Default metric: 1
      Topology default (ID 0)
        Type: PointToPoint, Node ID: 100.100.100.2
          Metric: 1, Bidirectional
      Aging timer 00:54:48
      Installed 00:05:09 ago, expires in 00:54:48
      Last changed 00:05:14 ago, Change count: 1​

    Elvin




  • 5.  RE: Juniper documentation question

    Posted 08-07-2021 13:45
    I saw your last reply  which I tried to mark the best answer. I do not know why it disappeared  after I licked Post button.

    I like to that explanation.

    thanks so much !!