[cisco-voip] Getting IOS to translate from DSCP to 802.1p

[Tim Smith]

Hi James,

It might be worth tidying up, but I'd be surprised if that was the cause of
this issue.

What version of CUCM are you running?
Do you have a Webex Control Hub and Connected UC setup yet?
(If you don't have Flex and Control Hub - a partner could spin up a trial
to use temporarily).

This integration is really useful.. especially for intermittent issues.
It's going to give you a read on all the calls that go through and their
quality.
So you can pin-point issues, and then dive into them.
You can also then get TAC to work these things directly (they can actually
pull traces as well).
But having the consolidated list of calls and quality is a game changer
(especially spotting patterns etc).
And of course it is really quick and easy to set up if you have some spare
VM space.

Otherwise, old school, I'd be looking at the media flows (is there anything
else in the path - i.e. an MTP, DSP etc that could be introducing an issue
on some calls) - where are the problematic calls traversing etc.
When you have some more info on the paths - you can always look at the old
Wiresharks.. rotating capture buffers.
Unless you have a nice network with some built in capture capability - like
Meraki!


Cheers,

Tim



On Fri, 24 Jun 2022 at 14:29, James Andrewartha <jandrewartha at ccgs.wa.edu.au>
wrote:

> Hi voipers,
>
>
>
> We have persistent reports of garbled voice quality (like when a mobile
> phone call glitches briefly) in one location on our campus, of course never
> when I’m there to observe it and get a capture. One thing I’ve noticed is
> the 802.1p priority isn’t being set on the packets. The setup is CUCM on
> VMware connected to a portgroup of VLAN 101. There’s also a 4331 which
> handles SIP termination on VLAN101. These are then routed by a (HSRP
> redundant pair of) 2921 to VLAN100 where the phones live. The 2921 doesn’t
> map the DSCP set by CUCM or 4331 to an 802.1p priority after routing, and
> for the life of me I can’t work out how to do it. I can’t work out how to
> do it on the 4331 either, I could move routing of the subnets to it but I
> was waiting until I got the second one which I ordered months ago arrives.
>
>
>
> Googling is useless, I end up with results for different variants of IOS
> or switches, none of which work on IOS 15 on the 2921. Surely it’s not that
> hard to just say “trust DSCP and map it to 802.1p”?
>
>
>
> Thanks,
>
>
>
> --
>
> James Andrewartha
>
> Network & Projects Engineer
>
> Christ Church Grammar School
>
> Claremont, Western Australia
>
> Ph. (08) 9442 1757
>
> Mob. 0424 160 877
>
>
> _______________________________________________
> cisco-voip mailing list
> cisco-voip at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-voip
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