Showing results for 
Search instead for 
Did you mean: 

Jabber (for Windows/MAC) QoS Behaviour


Can I ask a few questions about how Jabber would behave in a few QoS scenarios as I'm having difficulty finding this information in the SRND:

1. Is Jabber clever enough to mark audio and video traffic differently?

2. What QoS makings would be made to RTP packets by the Jabber client when:

     i. An Audio Call is made?

     ii. A Video Call is made?

3. What happens to an audio call when elevated/changed to a video call (from a QoS perspective) and vice versa?

4. If Jabber can dynamically change the QoS values based on the type of call (audio or video) when in a video call, will the audio traffic be marked with the same markings as the video call to ensure there are no lip sync issues?

Ideally we would expect that Jabber would behave as a IP Softphone (CS3 for signalling and EF for RTP) when in an audio call, but as a Video Endpoint (CS3 for signalling and AF41 for RTP)

Any insights would be appreciated.

5 Replies 5

Muhammad Maqsood Mushtaq
Cisco Employee
Cisco Employee


Jabber for Windows provides QoS via Cisco Medainet. This is documented in the Admin Guide. For further information on Cisco Medianet, please check following link.



So what you're saying is, without a medianet enabled network, Cisco Jabber for Windows media flows will be untagged, and will traverse the network as best effort traffic?

Hi Bendelongis

Here are my answers to your question as per my understanding.

1.  Traffic classification in a wireless device is depend on its wireless  driver hardware/operating system (jabber client is running on top of  that). If wireless device is WMM certified generally we would expect it  to differentiate traffic in to one of Voice/Video/Besteffort/Background  categories. According to this, wireless frame have a tag called User  Priority and traffic get prioratize within the wireless cell based on  this value.

2. Again this is depend on what type of wireless  client you have. Jabber application cannot determine this 100%. UP value  is the key to prioratise traffic within the wireless media. Some Apple  devices (like iPhones, MacBooks) do classify RTP audio/video as UP-5  while some apple devices (like iPads) does not do these correct  classification. Windows devices by default does not do these  classification on its wireless frames.

3. I think RTP  traffic will mark with same UP values & hence no differentiation  between audio or video as long as it use same RTP port ranges  (16384-32767)

4. same as point # 3

I  have done testing with few different types of BYOD with Cisco jabber  installed on it. Have a look at below post which summarized my test  results. It may help you to understand this better.



I can't find the answer to #1 on this thread.  Does Jabber for MAC try to mark its pakcets with DSCP values?  In Windows 7 the OS will not let you do it.  So does MAC OSX let you do it?

regardless of what you can or can not do farther up the stream, I just want to know if Jabber for Mac will try.  I don't have one to test and sniff myself.


J4M 9.2.1 does perform DSCP marking on audio and video RTP streams.

The DSCP values are defined in CUCM .