rate-limit question

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Dec 11th, 2007
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Is this correct?

A 5Mb link burstable to 10Mb. The following command:

rate-limit output 5000000 2500000 5000000 conform-action transmit exceed-action drop

would allow a 5Mb link with 2.5Mb bursts (=1.5 seconds) upto 5Mb or 10Mb total

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Overall Rating: 3 (1 ratings)
guruprasadr Tue, 12/11/2007 - 23:06
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HI, [Pls Rate if HELPS]


>>Average rate in bits per second. The value must be in increments of 8 kbps.


>>Normal burst size in bytes. The minimum value is bps divided by 2000.


>>Excess burst size in bytes.

The above is the logic in QOS rate-limit calculation.

Do Rate if HELPS

Best Regards,

Guru Prasad R

fallonem82 Wed, 12/12/2007 - 06:55
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Lets try this again and I'll use proper bit numbering instead of rounding

rate-limit output 5242880 2622 655360 conform-action transmit exceed-action drop

this command will allow a 5Mb connection with a normal-burst of 2622Bytes (5242880/2000) upto a max burst of 5Mb (5242880/8) effectively allowing a 5Mb link to burst to a total of 10Mb

Is this right or am I WAY off?

guruprasadr Wed, 12/12/2007 - 20:33
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HI, [Pls Rate if HELPS]

"2000" is the default value for normal-burst and max-burst and do follow the same if the link capacity is only 5 Mb.

Consider the Link is 10 Mb where internet traffic is limited to 5 Mb means:

rate-limit input access-group 100 5000000 1000000 1000000 conform-action transmit exceed-action drop

In the above Eg:

>>5 Mb of normal traffic

>>1 Mb of Normal Burst

>> 1 Mb of Max Burst

Hope this is Informative


Best Regards,

Guru Prasad R


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