Re: Ping TOS to test QOS...

> Yikes guys! I meant IPP to DSCP = IPP value * 8 and then DSCP to TOS =
> DSCP value * 4...sorry I mistyped that statement below.

Basically if you have an IP Precedence of 5 then its corresponding DSCP
value is 40 and corresponding TOS value is 160. EF (DSCP 46) as TOS is 184
etc.

IP Prec - 3 bits
DSCP - 6 bits
TOS - 8 bits

Hope that helps,

Jason

>
> -----Original Message-----
> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
> Jason Madsen
> Sent: Wednesday, 22 April 2009 5:17 PM
> To: Modular
> Cc: Cisco certification
> Subject: Re: Ping TOS to test QOS...
>
> Yes, you can test using the TOS CLI extended ping setting. As for the
> conversions, IPP to TOS = IPP value * 8 and DSCP to TOS = DSCP value * 4.
> Don't forget that if you're going through a switch and QoS is enabled, all
> interfaces are "not trusted" by default.
>
> Note, that if you have a real lab and also want to test with a Windows PC,
> there is a "-v" TOS option at the command line, but you will have to modify
> your TCP/IP settings in your registry for it to actually work...at least in
> some versions. The TOS feature in Cisco devices works fine out of the box
> though.
>
> Jason
>
> On Wed, Apr 22, 2009 at 3:07 PM, Modular <modulartx_at_gmail.com> wrote:
>
> > I had a thought, (don't laugh, it happens), is it possible to use the TOS
> > setting
> > in extended Ping to test QOS classification? I did a little research on
> > conversion
> > of TOS byte setting to IPP or DSCP and the best I could come up with is
> > that
> > a TOS of 1 or 8 would convert to IPP 1 or DSCP 8? I played around with it
> > for awhile, setting up a policy-map to match DSCP 1, DSCP 8 and IPP 1
> > and then set to TOS in the extended ping on a different router to 1 and
> > none of the class maps in the policy map had packet counts greater than
> 0.
> >
> > Either I'm converting TOS to IPP/DSCP wrong or I'm completely off base
> with
> > this.?.?
> >
> >
> > Bryan R.
> >
> >
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Received on Wed Apr 22 2009 - 15:31:39 ART