From: Petr Lapukhov (petrsoft@gmail.com)
Date: Tue May 16 2006 - 12:34:53 ART
Julius,
While I'm trying to get my mind in full sync with that topic,
let me note, that "class-default" is useless with catalyst 3550.
You need to police within specific class, matching either
IP or non-IP traffic. If you need to police both types to a single
rate, you should use aggregate policer.
Just try setting policer's rate/burst to minimal values within
"class-default", and do a simple ping test, to see that traffic
is not policed in that configuration.
HTH
Petr
2006/5/16, Julius Kinsler <jkinsler@harbortech.com>:
>
> This is the same article I was reading yesterday. It so happen to be that
> I was trying to do policing on a 3550.
> For example I created a policy-map and under the policy map, for the
> default class I put in the keyword
> police 1000000 <Normal Burst bytes> exceed action drop. I didnt completely
> understand the normal burst bytes I just wanted to police at 1Mbps.
> When I looked it up I came across the link below and was trying to
> interpret this Interval to come up with the normal burst bytes. I came to
> believe that this can be an arbitrary number based on the specifications in
> a practice lab.
> I was doing an IPExpert lab and the answer looked like this:
>
> mls qos
> policy-map MyPolice
> class class-default
> police 1000000 187500 exceed drop
>
> Now I was racking my brain trying to come up with the logic behind the
> number "187500" but I believe the number was made up after everything I
read
> about rate/intervals/and burst as stated below.
> Please tell me if I am wrong
>
> Julius
>
> ------------------------------
> *From:* Petr Lapukhov [mailto:petrsoft@gmail.com]
> *Sent:* Tuesday, May 16, 2006 1:17 AM
> *To:* Chris Lewis
> *Cc:* Julius Kinsler; ccielab@groupstudy.com
> *Subject:* Re: Policing
>
> Chris,
>
> There is an interesting thing they say about 3550 policing:
>
>
>
http://www.cisco.com/en/US/products/hw/switches/ps646/products_tech_note09186
a00800feff5.shtml
>
> Specifically:
>
> ---- quote
>
> These parameters control the operation of policing:
>
> - Rate - defines how many tokens are removed at each interval. This
> effectively sets
> the policing rate. All traffic below the rate is considered in profile.
> Supported rates
> range from 8 Kbps to 2 Gbps, and increment by 8 Kbps.
>
> - Intervaldefines how often tokens are removed from the bucket. The
> interval is fixed
> at 0.125 milliseconds (or 8000 times per second). This interval cannot be
> changed.
>
> - Burstdefines the maximum amount of tokens the bucket can hold at any
> time.
> Supported bursts range from 8000 bytes to to 2000000 bytes, and increment
> by 64 bytes.
> ---- quote
>
> I wonder if they do actually use *leaky* bucket with 3550 policer and
> *token*
> bucket (metering) with CAR/IOS Policer..
>
> Petr
>
> 2006/5/16, Chris Lewis <chrlewiscsco@gmail.com>:
> >
> > Julius,
> >
> > You are mixing two concwpts here. There is no Tc in policing that
> > adheres to
> > the shaping formula quoted. Policing does not calculate things at
> > regular
> > intervals, it calculates tokens to be credited and removed from the
> > bucket
> > based off packet arrival times.
> >
> > Chris
> >
> >
> > On 5/15/06, Julius Kinsler <jkinsler@harbortech.com > wrote:
> > >
> > > Using the standard equation CIR = Bc / Tc where can I find the Tc when
> > > trying to complete this formula?
> > >
> > > TIA
> > > Julius
> > >
> > >
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