QoS: difference between bandwidth and police?

[webstd.design]

What is difference between bandwidth and police?

[brianmahler]

Bandwidth is a minimum guarantee.

Police (and shaping) are maximum amounts.

[foxbatreco]

bandwidth in QOS terms defines the minimal throughput assured to that traffic class in the event of congestion & is based on the interface bandwidth.it defaults to not more than 75% of ur interface b/w.

Policing is basically restricting traffic class to a certain configured bandwidth if it tries to move over the allocated rate.its a stricter means of dropping the traffic and has options with it to either drop or mark it down&pass with lower priorities as configured.

Pls rate/mark if this helps!!!

[n.nandrekar]

hi!

I would rather say that "bandwidth" is a way of implementing class based queueing. It provides the minimum guarantee for the traffic. It will reserve that minimum bandwidth for your traffic class even in cases of congestion. so your traffic can exceed that bandwidth if there is no congestion and more bandwidth is available.

Policing is rather the upper limit for your bandwidth for that class. A policer when configured with drop, will meter the traffic flow on the link and will not allow that traffic to exceed the configured value. It will NOT provide any minimum guarantee and the traffic can be hampered in cases of congestion.

So.... to summarize,

Bandwidth - min guarantee, (lower threshold)

Police - Maximum limit ( upper threshold)

It is advisable to use bandwidth + policing if you want to guarantee some minimum bandwidth for your class and at the same time limit it to a maximum bandwidth that it can consume.

Hope this clears the doubt.

Regards,

Niranjan

(pls rate if helpful)