Routing

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

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

Hi Alex,

And thanks for answering 😉

I was talking about IP precedence.

Thanks again,

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 

Many thanks Alex !