Mailing List Archive: Does PQ/CBWFQ work on 3640 Ethernet IF

Hello,

I'm fairly new to this but am running IOS 12.1(5)T on a cisco3640 and am trying to implement some/any priority queueing of my voice on a 10Mg Ethernet IF. It seems that you can configure anything.. but that doesn't mean it will run, so from the release notes it appears I cannot do CBWFQ or PQ on this interface, however the Cisco feature navigator says I can. I tried to test them both and it seems that they are matching correctly and being queued correctly but changing the voice class queue limit seems to have no effect on the delay of my udp packets (i.e. they are being queued behind the tcp no matter?). So are the config commands being ignored? (but my packet losses indicate some effect in changing queue limit).
Ultimately, what form of PQ can I run for voice in my setup?

Regards
Paul

Yes, llq should be supported on the ethernet interface but have not really
seen a working need for it on a lan interface. Are you experiencing voice
quality problems currently without it?

How are you stressing the load on the interface to make sure that you are
able to test a difference in delay? How are you measuring the delay on your
network? You would need to make sure you have congestion on the interface
so that the PQ portion of llq can kick in. Unfortunately if you are doing
this, I would expect you will likely see other issue though on the
half-duplex (assuming that this is) ethernet interface once you start to
cross 40% or so utilization as I recall. You would likely need to implement
traffic shaping on the interface as well to throttle the traffic out to a
lower limit which then the PQ could kick in with the congestion occurring
now on the interface.

I looked at one of the enterprise design guides listed below, but again here
I don't see reference made to running this on a lan interface on the
gateway; though some time is spent on setting up various qos levels on the
switch based on dscp components which can be set on the 3640 GW with the
dial-peer subcommand "ip qos".

Bryan

http://www.cisco.com/application/pdf/en/us/guest/netsol/ns17/c649/ccmigratio
n_09186a00800d67ed.pdf

-----Original Message-----
From: cisco-voip-bounces@puck.nether.net
[mailto:cisco-voip-bounces@puck.nether.net]On Behalf Of Paul Plantinga
Sent: Wednesday, July 23, 2003 2:59 AM
To: cisco-voip@puck.nether.net
Subject: [cisco-voip] Does PQ/CBWFQ work on 3640 Ethernet IF

Hello,

I'm fairly new to this but am running IOS 12.1(5)T on a cisco3640 and am
trying to implement some/any priority queueing of my voice on a 10Mg
Ethernet IF. It seems that you can configure anything.. but that doesn't
mean it will run, so from the release notes it appears I cannot do CBWFQ or
PQ on this interface, however the Cisco feature navigator says I can. I
tried to test them both and it seems that they are matching correctly and
being queued correctly but changing the voice class queue limit seems to
have no effect on the delay of my udp packets (i.e. they are being queued
behind the tcp no matter?). So are the config commands being ignored? (but
my packet losses indicate some effect in changing queue limit).
Ultimately, what form of PQ can I run for voice in my setup?

Regards
Paul