[c-nsp] Question about Dual-rate Policing

[Paolo Lucente]

Hi Abo Zaid,

well, remember burstiness is a traffic quality, not a policer quality. Apart
from that, yes, you are correct.

The policer can be just configured to cope with bursts either as a one-off
action after a period in which tokens have not been drained away from the Bc
bucket (single rate, dual token) or as a rule because the Bc/Be buckets are
re-filled in parallel (dual rate, dual token).

This means that a bursty flow, depending on the bursts, can hit the policer
:-) but this also means that a steady flow sF, ie. like video streaming, will
never hit the policer if:

a) sF <= Bc bytes/s if a single rate dual token policer is configured

b) sF <= Bc+Be bytes/s if a dual rate dual token policer is configured

Cheers,
Paolo

On Sat, Dec 01, 2007 at 11:05:00AM +0200, Ibrahim Abo Zaid wrote:
> Dear All
> 
> i have a single question about dual-rate dual-bucket policing , according to
> the operations order
> 
> if the packet size conforms Bc and Bp buckets , an packet-size equivalent #
> of token is removed from both Bc and Bp buckets
> 
> My question is : does that mean that a steadier and constant confirming flow
> prevents any bursts ?
> 
> your comments are welcomed .
> 
> 
> best regards
> ~Abo Zaid