DSCP for Audio Portion of Video Calls does not apply while using jabber with deskphone control

[alexandre.ratel]

Hello,

I would like to know if somebody already played with jabber with deskphone control and DSCP marking  during a video call ?

Let me explain my case : I have got a jabber for windows controlling a 7821 deskphone. Everything works perfectly using audio only. Now when I proceed with a video call, the video initiate on the computer and the voice on the phone as expected. But I experience a bad audio quality. When I have a look at the DSCP marking using wireshark, I can see that switching to video, change the DSCP marking of the voice packets issued by the phone from EF to AF41. This is apparently the expected behavior according to the following CUCM setting : "DSCP for Audio Portion of Video Calls".

Here, according to this setting, the voice during a video call is tagged differently (AF41), explaining the bad quality.

Now I changed the setting "DSCP for Audio Portion of Video Calls" to "EF" as it is the normal prioritized DSCP value in my network. I checked that the value was correctly updated at the phone level (I checked the phone configuration file) but the behavior remains the same. The DSCP tag is still changed when the phone is used for the audio during a video call.

So is there anybody who has any experience about that ? Is this behavior normal ? Maybe this parameter doesn't apply for jabber call video with deskphone control ?

In addition :

- CUCM version : 10.5.2.13901-2

- Jabber version : 11.1.0

- 7821 version : sip78xx.11-5-1-18 (I tried with a 6921 too)

Best Regards

[Dennis Mink]

Video is tagged af41 as per design.  depending on your WAN provider and the way QoS is defined, it could be a probably. I have seen many cases where both ef and af41 are grouped as CS5, 

cisco's best practise is to split the two up. If in your case af41 is given considerably less bandwidth then ef then I would argue to group the two together in the same bandwidth class, but still be able to distinguish between them.

cheers

[alexandre.ratel]

Thanks a lot for your answer but my question is much simpler. I am just asking why the "DSCP for Audio Portion of Video Calls" parameter doesn't affect my phone ? I definitely need to let the voice call tagged as EF and don't want it to switch to AF41 when the video is turned on.

[j.a.m.e.s]

Hi Alexandre,

I've been looking at using this setting, but for some 9971 and 8865 phones. When I get round to testing this, I will let you know.

Have you seen the BRKUCC-2667 slides on this subject? An alternative approach might be to maintain separate port ranges for audio and video then mark traffic on your access switch:

* Set video port range (Device -> Phone) or use Common Phone Profile

* Set audio port range (Device -> Settings -> SIP Profiles)

Regards

James.