Routing

Expand all | Collapse all

Set a specific precedence value to a list of Prefixes associated to a specific as-path-group

Jump to Best Answer
  • 1.  Set a specific precedence value to a list of Prefixes associated to a specific as-path-group

    Posted 22 days ago

    Hi all,

     

    I would have liked to know please how such configuration could be performed on PTX running Junos:

    For a given as-path-group, i want to apply a specific precedence value to the prefixes associated to it.

     

    Thanks for your help,

    Jeyriku

     



  • 2.  Re: Set a specific precedence value to a list of Prefixes associated to a specific as-path-group

    Posted 22 days ago

    Hello,

    Is that IP Precedence, BGP Local Preference, or Preference (Cisco equivalent==Admin Distance) You want to apply to these prefixes?

    There is no "Precedence" is JUNOS as such.

    HTH

    Thx

    Alex



  • 3.  Re: Set a specific precedence value to a list of Prefixes associated to a specific as-path-group

    Posted 22 days ago

    Hi Alex,

     

    And thanks for answering 😉

    I was talking about IP precedence.

     

    Thanks again,



  • 4.  Re: Set a specific precedence value to a list of Prefixes associated to a specific as-path-group
    Best Answer

    Posted 22 days ago

    Hello,

     

    If You want to mark IP packets destined to BGP prefixes that fall into specific AS_PATH group, then You need to use Juniper feature called "Destination Class Usage"/DCU.

    If You want to mark IP packets sourced from BGP prefixes that fall into specific AS_PATH group, then You need to use Juniper feature called "Source Class Usage"/SCU

    https://www.juniper.net/documentation/en_US/junos/topics/concept/source-class-usage-options-junos-nm.html

     

    Then You can match the SCU or DCU value in a forwarding-table output FW filter, and assign DSCP or Forwarding Class/FC, or both. If You assign just FC, then You should also have class-of-service rewrite rule for this FC configured. 

    HTH

    Thx

    Alex

    P.S. The equivalent CSCO feature is called QPPB 



  • 5.  Re: Set a specific precedence value to a list of Prefixes associated to a specific as-path-group

    Posted 21 days ago

    Many thanks Alex !