[cisco-voip] auto QoS for Ip telephony solution

[Ed Leatherman]

Revisiting this thread since it seemed most related to my question.

As below, i've mainly been using "auto qos voip trust" on our interfaces
between cat 3750 switches. I've been going through the qos documentation,
particularly the SRND for enterprise qos - basically what it seems to be is
there are alot of differences between running "auto qos" and the recommended
configuration that they provide in the srnd.

One particular thing that just jumped out at me today was, using auto qos
voip trust on an interface doesn't appear to enable the priority queue
(according to the "sh mls qos int queueing" command). If that's true i've
got a ton of switches out there that need their configs fixed.. All my
traffic comes out marked OK, and queueing and so forth are setup OK on our
core routers but 90% of our distribution and access layer switches are 3550
or 3750 models.

So is auto-qos flat out not intended for anything but trusted endpoints such
as ccm servers? the further I dig into this the more it seems like this is
the case.


On 9/18/06, Erik Erasmus (E) <ErasmuE4 at telkom.co.za> wrote:
>
>  Thanks Ed
>
> I think it sound like good advice - I was basically planning to try it
> like you say.
> If one does not have extensive resources it is a lot easier and possibly
> good enough in most cases to use auto QoS.
>
> thanks for your advice - will let the group know if during my
> implementation I see something interseting.
>
> ------------------------------
> *From:* Ed Leatherman [mailto:ealeatherman at gmail.com]
> *Sent:* Mon 2006-09-18 16:29
> *To:* Erik Erasmus (E)
> *Cc:* cisco-voip at puck.nether.net
> *Subject:* Re: [cisco-voip] auto QoS for Ip telephony solution
>
> Hi Erik,
>
> I'm no qos expert by any stretch, this is just what we do and it seems to
> work out for us.. traffic markings come out end-to-end how we want them to
> at least. If someone else sees something wrong with it i'd love to hear it.
>
> I've been using "auto qos voip trust" on both those instances, i've been
> adding to that "mls qos trust dscp" to the callmanager ports and layer 3
> links, because the auto trust statement seems to put mls qos trust cos
> instead. To my understanding the callmanager servers mark their traffic with
> the dscp bits.
>
> Ed
>
> On 9/18/06, Erik Erasmus (E) <ErasmuE4 at telkom.co.za> wrote:
> >
> >
> > Currently at branches we use auto-QoS VoIP cisco-phone on all the 3560
> > series switchports connection to cisco phones and the same at HQ on the 4500
> > series switches.
> >
> >
> >
> >    1. I want to know what is recommended for the trunk interface on
> >    the switch between the branch gateway and the lan switch on the
> >    802.1Q trunk and also on the router main / subinterfaces.
> >    2. Also what is recommended on switch ports connecting to the
> >    Cisco Call Manager at HQ. Is it auto QoS VoIP trust ???
> >
> >
> Ed Leatherman
Senior Voice Engineer
West Virginia University
Telecommunications and Network Operations
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