Re: 3650 COS/DSCP to queue mapping

Joe, thanks for this test and deep dig on 3550/3560 guides!
Another great lesson learned from GS!
Looking forward to test this on 3550.

@ccie99999
Il giorno 05/set/2012 09:08, "Joe Astorino" <joeastorino1982_at_gmail.com> ha
scritto:

> In an effort to make sure I am not completely losing my mind I set out
> to figure out where I had gotten this notion. I believe it is
> something I learned back in the day about the catalyst 3550 and NOT
> the 3560. Check this out from the 3550 software configuration guide
> here:
> http://www.cisco.com/en/US/docs/switches/lan/catalyst3550/software/release/12.1_19_ea1/configuration/guide/swqos.html#wp1023211
>
> "Before the traffic reaches the scheduling stage, QoS uses the
> configurable DSCP-to-CoS map to derive a CoS value from the internal
> DSCP value. Through the CoS-to-egress-queue map, the CoS values select
> one of the four egress queues for output processing."
>
> In the same section (look for "mapping tables") in the 3560 guide,
> this has been changed to read:
>
> "Before the traffic reaches the scheduling stage, QoS stores the
> packet in an ingress and an egress queue according to the QoS label.
> The QoS label is based on the DSCP or the CoS value in the packet and
> selects the queue through the DSCP input and output queue threshold
> maps or through the CoS input and output queue threshold maps"
>
> NOW...since I just so happen to have some 3550's here in my home lab I
> re-ran the same test and received the same results we did with the
> 3560 as far as MARKING is concerned. But I believe what the 3550
> guide here is saying is that the output queue was based on the
> internal mapping. So, on the 3550 I believe we had the CoS mapped to
> internal DSCP then internal DSCP mapped to CoS and CoS mapped to
> output queue. Seems the output queue was effected by the internal
> mappings, but not the marking itself
>
> So in summary -- It looks like based on testing and documentation that
> the 3550 did something like I was saying at least for outbound
> queueing but that the 3560 has a different approach
>
>
> On Wed, Sep 5, 2012 at 1:36 AM, ccie99999 <ccie99999_at_gmail.com> wrote:
> > sorry.. Joe.. just reloaded everything and I cannot use those switches
> now.
> >
> > anyway.. nothing special:
> >
> > pc1 side: cos3 + cos override.. as explained in the test
> > pc2 side: nothing.. no trust, no override.. nothing..
> >
> >
> >
> > On Wed, Sep 5, 2012 at 5:25 AM, Joe Astorino <joeastorino1982_at_gmail.com
> >wrote:
> >
> >> 99999,
> >>
> >> Can you post your configurations? I would like to see on both
> >> interfaces what you have configured for trust and other things.
> >>
> >> On Tue, Sep 4, 2012 at 1:46 PM, marc edwards <renorider_at_gmail.com>
> wrote:
> >> >
> >>
> http://www.cisco.com/en/US/docs/switches/lan/catalyst3750x_3560x/software/release/12.2_58_se/configuration/guide/swqos.html#wp1023954
> >> >
> >> >
> >> > Chart really says it all. What I find interested and (supporting your
> >> view)
> >> > is the fact that DSCP-to-CoS is never used....
> >> >
> >> > On Tue, Sep 4, 2012 at 9:04 AM, marc edwards <renorider_at_gmail.com>
> >> wrote:
> >> >
> >> >> So on those thoughts.... We need to trust dscp. trusting cos
> throughout
> >> >> will bypass switch from looking at dscp markings. trusting dscp will
> >> make
> >> >> switch look into packet to see dscp markings and use mappings to
> >> convert a
> >> >> cos value. This should hit the dscp-cos map and reference values from
> >> >> altered config.
> >> >>
> >> >> Marc
> >> >>
> >> >>
> >> >> On Tue, Sep 4, 2012 at 8:55 AM, marc edwards <renorider_at_gmail.com>
> >> wrote:
> >> >>
> >> >>> So... looks like you are tagging frames on PC NIC? Where is vlan 1
> >> vlan 2
> >> >>> config or are these PC's in same VLAN/subnet? Where is 'mls qos
> trust
> >> cos'
> >> >>> on fa 0/2?
> >> >>>
> >> >>> Marc
> >> >>>
> >> >>>
> >> >>> On Tue, Sep 4, 2012 at 8:46 AM, ccie99999 <ccie99999_at_gmail.com>
> wrote:
> >> >>>
> >> >>>> Command was like: MLS qos map dscp-cos 24 to 5
> >> >>>>
> >> >>>> Show mls QoS dscp-cos shows it's mapped correctly
> >> >>>> Il giorno 04/set/2012 17:35, "marc edwards" <renorider_at_gmail.com>
> ha
> >> >>>> scritto:
> >> >>>>
> >> >>>> > 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
> >> >>>> >> >> > >>
> >> >>>> >> >> >
> >> >>>> >>
> >> >>>>
> >> >>______________________________________________________________________
> >> >>>> >> >> > >>_ Subscription information may be found at:
> >> >>>> >> >> > >>http://www.groupstudy.com/list/CCIELab.html
> >> >>>> >> >> > >
> >> >>>> >> >> > >
> >> >>>> >> >> > > Blogs and organic groups at http://www.ccie.net
> >> >>>> >> >> > >
> >> >>>> >> >> > >
> >> >>>> >>
> >> ______________________________________________________________________
> >> >>>> >> >> > > _ Subscription information may be found at:
> >> >>>> >> >> > > http://www.groupstudy.com/list/CCIELab.html
> >> >>>> >> >> > >
> >> >>>> >> >> > >
> >> >>>> >> >> > >
> >> >>>> >> >> > >
> >> >>>> >> >> > >
> >> >>>> >> >> > >
> >> >>>> >> >> > >
> >> >>>> >> >> >
> >> >>>> >> >> >
> >> >>>> >> >> >
> >> >>>> >> >> > --
> >> >>>> >> >> > Regards,
> >> >>>> >> >> >
> >> >>>> >> >> > Joe Astorino
> >> >>>> >> >> > CCIE #24347
> >> >>>> >> >> > http://astorinonetworks.com
> >> >>>> >> >> >
> >> >>>> >> >> > "He not busy being born is busy dying" - Dylan
> >> >>>> >> >> >
> >> >>>> >> >> >
> >> >>>> >> >> > Blogs and organic groups at http://www.ccie.net
> >> >>>> >> >> >
> >> >>>> >> >> >
> >> >>>> >>
> >> >>>>
> >> _______________________________________________________________________
> >> >>>> >> >> > Subscription information may be found at:
> >> >>>> >> >> > http://www.groupstudy.com/list/CCIELab.html
> >> >>>> >> >> >
> >> >>>> >> >> >
> >> >>>> >> >> > Blogs and organic groups at http://www.ccie.net
> >> >>>> >> >> >
> >> >>>> >> >> >
> >> >>>> >>
> >> >>>>
> >> _______________________________________________________________________
> >> >>>> >> >> > Subscription information may be found at:
> >> >>>> >> >> > http://www.groupstudy.com/list/CCIELab.html
> >> >>>> >> >>
> >> >>>> >> >>
> >> >>>> >> >> Blogs and organic groups at http://www.ccie.net
> >> >>>> >> >>
> >> >>>> >> >>
> >> >>>>
> >> _______________________________________________________________________
> >> >>>> >> >> Subscription information may be found at:
> >> >>>> >> >> http://www.groupstudy.com/list/CCIELab.html
> >> >>>> >>
> >> >>>> >>
> >> >>>> >> Blogs and organic groups at http://www.ccie.net
> >> >>>> >>
> >> >>>> >>
> >> >>>>
> >> _______________________________________________________________________
> >> >>>> >> Subscription information may be found at:
> >> >>>> >> http://www.groupstudy.com/list/CCIELab.html
> >> >>>>
> >> >>>>
> >> >>>> Blogs and organic groups at http://www.ccie.net
> >> >>>>
> >> >>>>
> >> _______________________________________________________________________
> >> >>>> Subscription information may be found at:
> >> >>>> http://www.groupstudy.com/list/CCIELab.html
> >> >
> >> >
> >> > Blogs and organic groups at http://www.ccie.net
> >> >
> >> >
> _______________________________________________________________________
> >> > Subscription information may be found at:
> >> > http://www.groupstudy.com/list/CCIELab.html
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >>
> >>
> >>
> >> --
> >> Regards,
> >>
> >> Joe Astorino
> >> CCIE #24347
> >> http://astorinonetworks.com
> >>
> >> "He not busy being born is busy dying" - Dylan
> >
> >
> > Blogs and organic groups at http://www.ccie.net
> >
> > _______________________________________________________________________
> > Subscription information may be found at:
> > http://www.groupstudy.com/list/CCIELab.html
> >
> >
> >
> >
> >
> >
> >
>
>
>
> --
> Regards,
>
> Joe Astorino
> CCIE #24347
> http://astorinonetworks.com
>
> "He not busy being born is busy dying" - Dylan

Blogs and organic groups at http://www.ccie.net
Received on Wed Sep 05 2012 - 09:57:13 ART