Re: Policy-map / not reaching the required band

Ahmed Erfan Mehdi · ‎09-23-2013

Dear Friends,

We have set below policy as below:

Policy Map xxxxxxx

Class class-default

police cir 4354000000 bc 136062500

conform-action transmit

exceed-action drop

bc value is auto and our customer cant reach more that 4330 Mbps, if i remove the policy , he can reach 4600 Mbps.

Please advise.

Regards,

Ahmed

nkarpysh · ‎09-23-2013

Hello,

You need to tune the Bc. Traffic can be bursty thus not all can be send within Tc so you never reach CIR.

Niko

HTH,
Niko

Ahmed Erfan Mehdi · ‎09-23-2013

Hi mya friend,

thanks , how can i tune the bc value

Regards,

Ahmed Erfan

Joseph W. Doherty · ‎09-23-2013

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Posting

Ahmed Erfan Mehdi wrote:

Hi mya friend,

thanks , how can i tune the bc value

Regards,

Ahmed Erfan

Do you mean how you configure on what it should be configured to?

If the former, you just manually configure the BC with the police statement.

If the latter, that's rather complex. It's can be similar to tuning interface buffers. For your purposes, just try increasing, incrementally, until your users get the performance they expect.

Ahmed Erfan Mehdi · ‎09-23-2013

Hi My friend,

Thanks for your reply.

Right now i have set policy limit to 4400 Mbps and he is geting it right.

I want it to be 4354 Mbps, so how can i configure bc manually, how can i calculate the right value to fit the require band.

Regards,

Ahmed Erfan

Ahmed Erfan Mehdi · ‎09-23-2013

Hi my friend,

we can calculate it as below:

Bc (normal burst) = CIR / 8 * 1.5 seconds

4354000000/8 * 1.5 = 816375000

What do you think ?

Joseph W. Doherty · ‎09-24-2013

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Right now i have set policy limit to 4400 Mbps and he is geting it right.

I want it to be 4354 Mbps, so how can i configure bc manually, how can i calculate the right value to fit the require band.

Policing may not be sufficiently precise to distinguish that fine a bandwidth difference, especially over a short time interval.

Remember, unlike an interface that is actually transmitting bits at a physical rate, policers are averaging bits transmitted per packets and they pass or drop packets.