Routing

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Ask questions and share experiences about ACX Series, CTP Series, MX Series, PTX Series, SSR Series, JRR Series, and all things routing, including portfolios and protocols.

  • 1.  MX960 Change DSCP on ip header / similar to mangle function on iptables

    Posted 02-18-2014 08:08

     

    Hello guys , I need to filter and write on dscp field (0x20 = DSCP) on some especific packets,

    is there any good example about it ?

    Mine is a MX960 router.

    Any example would be pretiated

    Thanks! 

    Leo

     



  • 2.  RE: MX960 Change DSCP on ip header / similar to mangle function on iptables
    Best Answer

     
    Posted 02-20-2014 09:45

    This would be done with a combination of firewall filters on the ingress interface(s) and rewrite-rules.  I strongly suggest checking out the "Day One: Deploying Basic QoS" PDF:

     

    http://www.juniper.net/us/en/community/junos/training-certification/day-one/fundamentals-series/deploying-basic-qos/

     

    There are a few different hierarchies that need to be configured here: firewall filters, interfaces, rewrite-rules, and class of service interfaces.  One thing that is often overlooked is that Juniper rewrites packet headers on outbound, even though the filters are configured on inbound.   However, once you have your packets rewritten at the edge, it's possible to perform BA (behavior aggregate) classification on links further upstream from your edge, so you can keep the configurations a bit cleaner and standardized in the core.