From: PANDI MOORTHY (moorthypandi@gmail.com)
Date: Sun Mar 05 2006 - 00:48:12 GMT-3
Excellent, thank you.
Regards.
Pandi
On 3/5/06, Reinhold Fischer <Reinhold.Fischer@gmx.net> wrote:
>
> Hi Pandi,
>
> i came across the following statement in the book 'IP Quality of Service'
> (Ciscopress, Page 38):
>
> <cite>
> - Rate (bps) should be in increments of 8 Kbps, and the lowest value
> allowed for conformed and extended burst size is 8000 bytes.
> - The minimum value of BC size is Rate (bps) divided by 2000. It should be
> at least 8000 bytes.
> - The BE is always equal to or greater than the BC value.
> </cite>
>
> According to the calculation the BC value would be: 500000 / 2000 = 250
>
> So i would choose the recommended minimum value of 8000 bytes for BC and
> twice the size for BE:
>
> access-list 100 permit tcp any any syn
> access-list 100 deny ip any any
> int e0/0
> rate-limit output access-group 100 496000 8000 16000 conform-action
> transmit exceed-action drop
>
>
> There is another formula on cco on this URL:
>
>
>
http://www.cisco.com/en/US/tech/tk543/tk545/technologies_q_and_a_item09186a00
800cdfab.shtml#policing
>
> http://tinyurl.com/ouvcf
>
> which you can use to calculate the BC/BE values. This formula assumes
> a typical round-trip-time of 1.5 seconds and therefore the results
> for BC/BE produce higher numbers.
> When using this formula the BC value would be 93750 and the BE value
> would be 187500.
>
>
> hope this helps and is not too confusing :-)
>
> regards
>
> Reinhold
>
>
> On Sun, Mar 05, 2006 at 12:36:02AM +0800, PANDI MOORTHY wrote:
> > Hi
> >
> > The question is to limit the TCP sync traffic to 500kbps which is out
> from
> > the Ethernet interface.
> >
> > So I have to use the rate-limit command to achieve this, one thing still
> I
> > can't figure out is choosing the value for burst-normal and burst-max,
> > Anyone please advice me on this?
> >
> > Regards.
> > Pandi
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