Simple policing question

Unanswered Question
Aug 2nd, 2008


There is so much controversy on how to set certain rate with traffic policing that it is amazing!

I need to set a class-based policer to allow 5Mb/s on Ethernet link with burst up to 10Mb/s.

What values are needed for it?



I have this problem too.
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Marwan ALshawi Sat, 08/02/2008 - 18:18

read the following i think its applicable to ur question

acccording to cisco press:

CB Policing: Dual Token Bucket (Dual Rate)

Dual Token Bucket CB Policing with a single rate provides a very useful function. After a period of low activity, a larger burst of data can be considered to either conform to or exceed the traffic contract, without violating the traffic contract. Because data tends to be bursty, the idea of a policer with bursting capability makes a lot of sense

Dual Token Bucket with Dual-rate policing also provides a bursting feature, but with dual-rate, the CB Policer allows you to essentially set two different sustained rates. Packets that fall under the lower ratethe Committed Information Rate (CIR)conform to the traffic contract. A second sustained ratethe Peak Information Rate (PIR)defines a traffic rate above CIR. Packets that happen to exceed the CIR, but fall below PIR, are considered to exceed the contract, but not to violate it. Finally, packets beyond even the PIR are considered to exceed the contract

police {cir cir} [bc conform-burst] {pir pir} [be peak-burst]

[conform-action action [exceed-action action [violate-action action]]]

for ur question should be somthing like:

police cir 50000 pir 100000

where the CB Policing Defaults for Bc and Be


When dual-rate policing, For Be, IOS using a slightly-different formula, with the same intent, but based on PIR

Bc= (PIR*.25 second)/(8 bit/byte)= PIR/32

good luck

Please, if helpful Rate

dknov Sat, 08/02/2008 - 18:46


So could it also be

police 5000000 39062

Where 39062 (in bytes) is:

10000000bit(PIR) / 8 = 1250000byte(PIR)

and then according to your formula

1250000 / 32 = 39062 bytes

Marwan ALshawi Sat, 08/02/2008 - 18:52

but without the words cir and pir in the command it will not be dual rate policer

this will be a policer with its burst

like the CIR and Bc

so u need to follow the coman stracture that sent u and in the command stracture there is a curly brckets these are must and other option

so i sent u the calculation formula if u dont chane the optional numbers such as Bc and Be

good luck

please rate if helpful


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