Routing

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RSVP Preference

  • 1.  RSVP Preference

     
    Posted 12-04-2020 03:31
    Hi all.

    From the output below, RSVP has a preference of [7/1].

    user@R2> show route table mpls detail
       ...
    299776 (1 entry, 1 announced)
            *RSVP   Preference: 7/1
                    Next hop type: Router, Next hop index: 832
                    Address: 0xc4d8aa0
                    Next-hop reference count: 2
                    Next hop: 20.20.20.2 via ge-0/0/1.0, selected
                    Label-switched-path R1-R4
                    Label operation: Swap 299808

    What does the '1' in '7/1' stand for?

    Thanks,
    Deepak


  • 2.  RE: RSVP Preference

     
    Posted 12-04-2020 04:15
    Hi Deepak,

    > 3 values might be associated with RSVP Preference (7)

    It is predefined in JUNOS.

    The values are:

    1 -- normal RSVP-TE LSP.
    2 -- point-to-multipoint RSVP-TE LSP.
    3 -- dynamic RSVP-TE LSP (the one, created by the built-in auto-mesh functionality).

    Almost all the time we use the normal RSVP-TE LSP.

    For your reference, the below KB has an example of the "RSVP auto-mesh LSP"
    https://kb.juniper.net/InfoCenter/index?page=content&id=KB28156&actp=RSS


    Find  more information about "Point-to-Multipoint LSPs" in the below link
    https://www.juniper.net/documentation/en_US/junos/topics/topic-map/p2mp-lsp-configuration.html#id-pointtomultipoint-lsps-overview

    Hopefully this help.

    Regards,
    Bemwa 



  • 3.  RE: RSVP Preference

    Posted 12-05-2020 06:22
    Depending the type of RSVP-TE object describing the type of tunnels, you will have a preference given to it by Junos.

    Unless you have 'advanced' use cases (such as MVPN which could leverage Multipoint LSPs), you would mostly see the `RSVP 7/1 ` preference output.

    Good question.

    Regards,

    Elvin