CAR

Answered Question
Apr 24th, 2009
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Dear All,

In committed Access Rate the syntax is as follows

rate-limit {input | output} [access-group [rate-limit] acl-index | qos-group number] bps burst-normal burst-max conform-action action exceed-action action

e.x

rate-limit output 20000000 24000 24000 conform-action transmit exceed-action drop

Can any one explain how we achive Normal burst rate like

Burst Rate= CIR * (1/8) * 1.5

What is that 1.5 is for......


Many Thanks,

Saran

Correct Answer by Giuseppe Larosa about 8 years 2 days ago

Hello Saran,

in CAR configuration the second and the third parameters are the normal burst size and the extended burst size expressed in bytes.

They are the size of buffers that can hold packets.

The idea is to allow for some burstiness of traffic.


So going to the formula it says:


Burst Size [B ] = CIR [ bps ] * 1/8 [B/b] * 1,5 s


that 1,5 is a time interval expressed in seconds.


so the command says:

allocate X bytes for normal buffer to be able to accomodate 1.5 seconds of traffic at CIR rate.


Hope to help

Giuseppe


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Correct Answer
Giuseppe Larosa Sat, 04/25/2009 - 01:33
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Hello Saran,

in CAR configuration the second and the third parameters are the normal burst size and the extended burst size expressed in bytes.

They are the size of buffers that can hold packets.

The idea is to allow for some burstiness of traffic.


So going to the formula it says:


Burst Size [B ] = CIR [ bps ] * 1/8 [B/b] * 1,5 s


that 1,5 is a time interval expressed in seconds.


so the command says:

allocate X bytes for normal buffer to be able to accomodate 1.5 seconds of traffic at CIR rate.


Hope to help

Giuseppe


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