Voice over IP Cisco - auto QoS for Ip telephony solution

Author

auto QoS for Ip telephony solution

Erik Erasmus \(E\)

2006-09-18, 7:11 am

Hi

Does any one have good experience on the use of auto QoS in an IP
Telephony solution. The scenario is as follows. Centralised call
manager and remote branches with IP phones. Locations, regions etc.
All working fine. At remote branches we have a voice gateway with a
trunk to the local lan switch (two subinterfaces - one for data vlan
and one for voice vlan)

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 ???

The auto QoS on the phone ports are working fine and I would prefer to
use auto-QoS for the additional links too where possible, excluding
the WAN links on the MPLS cloud where we have configured QoS manually.
Mainly because it is easier and consistent.

Erik Erasmus

Telkom SA

': +27 12 680 8320

*: +27 12 680 7388

*: +27 82 4106420

*: erasmue4@telkom.co.za

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Ed Leatherman

2006-09-18, 1:11 pm

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@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 802.1Qtrunk 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

Linsemier, Matthew

2006-09-18, 1:11 pm

This is a good topic for discussion. I posted to this list a while back
about which cisco software packages, specifically their VoIP software
line, does and does not mark traffic before sending it on to the switch.
Because I have never received a firm answer, I always thought it to be a
best practice to mark / re-mark this traffic to be sure. If there was a
definitive with version numbers list I may default to trusting DSCP on
the switches using Auto-QoS. Until then, as long as re-marking the
traffic doesn't have significant overhead, I don't see the harm unless
your QoS remarking was misconfigured.

Any of you cisco guys want to shed some light on this?

-Matt

________________________________

From: cisco-voip-bounces@puck.nether.net
[mailto:cisco-voip-bounces@puck.nether.net] On Behalf Of Ed Leatherman
Sent: Monday, September 18, 2006 10:30 AM
To: Erik Erasmus (E)
Cc: cisco-voip@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@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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Erik Erasmus \(E\)

2006-09-18, 1:11 pm

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@gmail.com]
Sent: Mon 2006-09-18 16:29
To: Erik Erasmus (E)
Cc: cisco-voip@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@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

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~~~
This e-mail and its contents are subject to the Telkom SA Limited
e-mail legal notice available at
http://www.telkom.co.za/TelkomEMailLegalNotice.PDF
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~~~

Ed Leatherman

2006-11-13, 8:10 am

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@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@gmail.com]
> *Sent:* Mon 2006-09-18 16:29
> *To:* Erik Erasmus (E)
> *Cc:* cisco-voip@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@telkom.co.za> wrote:
> Ed Leatherman
Senior Voice Engineer
West Virginia University
Telecommunications and Network Operations

Erik Erasmus \(E\)

2006-11-13, 8:10 am

Ed

I did not really take time to investigate this in more detail. I have
a new implementation coming up and as one do - I am trying to improve
the way we deploy things, fix previous mistakes etc so hopefully will
have a bit of time in staging to look at what potentially is a good
way of doing it. Will let you know. Waiting for the kit to come in -
probably start early December.

Erik Erasmus

________________________________

From: Ed Leatherman [mailto:ealeatherman@gmail.com]
Sent: 10 November 2006 11:41 PM
To: Erik Erasmus (E)
Cc: cisco-voip@puck.nether.net
Subject: Re: [cisco-voip] auto QoS for Ip telephony solution

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@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@gmail.com]
Sent: Mon 2006-09-18 16:29
To: Erik Erasmus (E)
Cc: cisco-voip@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@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

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~~~
This e-mail and its contents are subject to the Telkom SA Limited
e-mail legal notice available at
http://www.telkom.co.za/TelkomEMailLegalNotice.PDF
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~~~