Re: 3650 COS/DSCP to queue mapping

can you please provide command entered for dscp-cos map config?

On Tue, Sep 4, 2012 at 8:31 AM, ccie99999 <ccie99999_at_gmail.com> wrote:

> I did cos 3 + cos override on pc1 side and trust dscp on pc2 side.
> I can't do a show mls qos maps now but I set up a dscp24 to cos5 mapping.
>
>
>
> On Tue, Sep 4, 2012 at 3:30 PM, marc edwards <renorider_at_gmail.com> wrote:
>
> > Can either of you do a sh mls qos maps? Also, please show access
> > interfaces config. My hunch is that the dscp-cos map hasn't been changed
> to
> > refelect dscp 24 as cos 05. I am also curious to see if you have trusted
> > cos or dscp on access. That will change things.
> >
> > Regards,
> >
> > Marc
> >
> >
> > On Tue, Sep 4, 2012 at 8:23 AM, ccie99999 <ccie99999_at_gmail.com> wrote:
> >
> >> I've labbed this (cos3->dscp24->cos5) and I see I receive cos3 on the
> >> second pc as well as dscp24.
> >>
> >> pc1(vlan1) - sw - pc2(vlan2)
> >>
> >> (I do trust cos on pc2 interface side).
> >>
> >> I guess it's fine I see dscp24.. don't understand why I see cos3.
> >>
> >> thanks
> >>
> >>
> >> On Tue, Sep 4, 2012 at 12:33 PM, gp <gs4me2me_at_gmail.com> wrote:
> >>
> >> > Hi Joe,
> >> >
> >> > I tried lab what you wrote, and not have result that I expected. So I
> >> have
> >> > one question; in your opinion what cos value will have frame when
> leave
> >> > switch: cos 3 or cos 5?
> >> >
> >> > I had cos 3, that confuse me.
> >> >
> >> > Thanks
> >> >
> >> >
> >> > -----Original Message-----
> >> > From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf
> Of
> >> > Joe
> >> > Astorino
> >> > Sent: Thursday, August 30, 2012 6:34 PM
> >> > To: Anthony Sequeira
> >> > Cc: Matt Eason; Cisco certification
> >> > Subject: Re: 3650 COS/DSCP to queue mapping
> >> >
> >> > Hi Matt,
> >> >
> >> > Anthony answered your question simply and correctly, but I just wanted
> >> to
> >> > add some things that helped me understand this. Like Anthony said,
> >> > whatever
> >> > you trust is basically how the switch determines the queue at a high
> >> level,
> >> > but at a deeper level there are a few different mappings going on.
> >> Let's
> >> > assume you trust CoS. You would have:
> >> >
> >> > - CoS to DSCP mapping INTERNAL to the switch
> >> > - DSCP to CoS mapping INTERNAL to the switch
> >> > - CoS to output queue mapping
> >> >
> >> > The point I am making is that even though a frame comes in with a
> >> > particular
> >> > CoS value, that value COULD change internally based on the internal
> >> > COS-DSCP
> >> > and DSCP-COS, and the frame COULD be queued based on the value derived
> >> from
> >> > the internal mappings and not on the original value. Let's look at
> some
> >> > example output for a second
> >> >
> >> > Here are some mapping tables for cos-dscp, dscp-cos and cos-output-q
> on
> >> a
> >> > 3750 switch. Note these are probably not default values because this
> is
> >> a
> >> > production switch.
> >> >
> >> > Here is the COS to DSCP mapping:
> >> >
> >> > switch#sh mls qos maps cos-dscp
> >> > Cos-dscp map:
> >> > cos: 0 1 2 3 4 5 6 7
> >> > --------------------------------
> >> > dscp: 0 8 16 24 32 40 48 56
> >> >
> >> > Here is the DSCP to CoS mapping
> >> >
> >> > switch#sh mls qos map dscp-cos
> >> > Dscp-cos map:
> >> > d1 : d2 0 1 2 3 4 5 6 7 8 9
> >> > ---------------------------------------
> >> > 0 : 00 00 00 00 00 00 00 00 01 01
> >> > 1 : 01 01 01 01 01 01 02 02 02 02
> >> > 2 : 02 02 02 02 03 03 03 03 03 03
> >> > 3 : 03 03 04 04 04 04 04 04 04 04
> >> > 4 : 05 05 05 05 05 05 05 05 06 06
> >> > 5 : 06 06 06 06 06 06 07 07 07 07
> >> > 6 : 07 07 07 07
> >> >
> >> > Finally, here is the CoS to output queue mapping
> >> >
> >> > switch#sh mls qos map cos-output-q
> >> > Cos-outputq-threshold map:
> >> > cos: 0 1 2 3 4 5 6 7
> >> > ------------------------------------
> >> > queue-threshold: 2-1 2-1 3-1 3-1 4-1 1-1 4-1 4-1
> >> >
> >> >
> >> > Let's just look at CoS 3 for example. We see that CoS 3 is mapped to
> >> DSCP
> >> > 24. In turn DSCP 24 is mapped right back to CoS 3 in the DSCP to COS
> >> > mapping. In turn, CoS 3 is put into output queue 3, threshold 1.
> >> > Fine. So in this case, it comes in as CoS 3 and is queued based on
> CoS
> >> 3
> >> > because we trust CoS and because the DSCP-COS mapping is sort of
> >> "synced".
> >> > But...what if you went in and mucked with the DSCP-COS mapping
> >> internally
> >> > such that DSCP 24 was no longer mapped back to CoS 3? What if it was
> >> > re-mapped to CoS 5 ?
> >> >
> >> > So you COULD have the frame come in as CoS 3 ...internally we go CoS 3
> >> > --> DSCP 24, then DSCP 24 to CoS 5 then queued based on CoS 5
> >> >
> >> > These are intricate details, but when you are studying for the lab, I
> >> think
> >> > it is important to get to the dirty details! Best of luck and I hope
> >> this
> >> > helps you out.
> >> >
> >> >
> >> >
> >> > On Thu, Aug 30, 2012 at 10:45 AM, Anthony Sequeira
> >> > <terry.francona_at_gmail.com> wrote:
> >> > > Hi Matt!
> >> > >
> >> > > What an AWESOME question. While the documentation does not make it
> >> > > clear, the value that you trust on ingress, in your example, CoS, is
> >> > > the marking that is used in the appropriate default queue mapping
> >> > > table on the egress port.
> >> > >
> >> > > Anthony Sequeira, CCIE, CCSI, VCP
> >> > > http://www.stormwind.com
> >> > > Twitter: @compsolv
> >> > > Facebook: http://www.facebook.com/compsolv
> >> > >
> >> > >
> >> > >
> >> > > On 8/29/12 9:11 PM, "Matt Eason" <matt.d.eason_at_gmail.com> wrote:
> >> > >
> >> > >>Hi Guys,
> >> > >>
> >> > >>
> >> > >>
> >> > >>Can you help clarify the following. If I have a switchport
> configured
> >> > >>on a
> >> > >>3560 to trust CoS inbound, that cos value is then mapped to an
> >> > >>internal DSCP value via the COS>DSCP map. That s fine.
> >> > >>
> >> > >>
> >> > >>
> >> > >>Does this switch then determine the output queue from the original
> CoS
> >> > >>value or the internal DSCP value which was assigned by the switch? I
> >> > >>see both a DSCP>Output queue map and a COS>Output queue map exists.
> >> > >>
> >> > >>
> >> > >>
> >> > >>Thanks,
> >> > >>
> >> > >>
> >> > >>
> >> > >>Matt
> >> > >>
> >> > >>
> >> > >>Blogs and organic groups at http://www.ccie.net
> >> > >>
> >> >
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> ______________________________________________________________________
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> >> > >
> >> > >
> >> > >
> >> > >
> >> > >
> >> > >
> >> > >
> >> >
> >> >
> >> >
> >> > --
> >> > Regards,
> >> >
> >> > Joe Astorino
> >> > CCIE #24347
> >> > http://astorinonetworks.com
> >> >
> >> > "He not busy being born is busy dying" - Dylan
> >> >
> >> >
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> >> >
> >> >
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Received on Tue Sep 04 2012 - 08:35:10 ART