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PBR using Interface utilization

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  • 1.  PBR using Interface utilization

    Posted 03-25-2020 16:09

    Hi everybody,

    I am wondering if I can implement the following;

    MX  ge -0/0/1---WAN ( Service provider1)

            ge-0/0/2----WAN ( Serie provider2)

     On MX, we use PBR which says following:

    1) if  ge-0/0/1 transmit rate is 80%, send the traffic out of ge-0/0/2

     As a design goal, we should avoid  using  MPLS based TE to steer the traffic to target path.

    Is it possibe to acheive the desired goal by using PBR alone on MX?


    Have a good weekend and stay safe!!














  • 2.  RE: PBR using Interface utilization
    Best Answer

    Posted 03-26-2020 00:42


    I reckon it would be possible with combination of RMON and event-script.

    JUNOS RMON https://www.juniper.net/documentation/en_US/junos/topics/task/configuration/rmon-qfx-series-cli.html can raise event on interface Bps exceeding threshold (800Mbps for 1GE, 8Gbps for 10GE and so on), and event-script can change routing table.

    You'd need to account for the following situations:

    1/ what is the time interval for asserting 80% ? 1 sec is too short, 5 min may be too long 

    2/ when ge-0/0/1 interface util is > 80%, do You want the  ge-0/0/2 to share the whole load with  ge-0/0/1, or only take a portion of it that exceeds 80%?

    3/ what to do when ge-0/0/1 util falls back below 80%? I suggest some hysteresis here, like waiting until it goes down below 70% to avoid flows bouncing between 2 interfaces/providers

    etc etc