[j-nsp] Rate limiting

[Timur Ibragimov]

Hello,

I have configured following policer

policer bw-1500k.5ms {
    if-exceeding { 
        bandwidth-limit 1500000;
        burst-size-limit 1500;
    }              
    then discard;  
}

believing it will rate limit traffic to 1500 Kbps. But it starts to drop
packets at much less than configured bandwidth-limit rates. When
burst-size-limit was strongly increased (150K) everything went well.

I read that JTAC suggests setting the burst-size-limit equal to the
amount of traffic forwarded by the interface in 5 milliseconds but I
can't figure out fundamentals for that suggestion. The appropriate
policer didn't work as I expected. Can anybody give some references
about setting allowable time for burst traffic?

Thanks