Getting dead air calls in cisco Jabber

[chandru_bbc]

We are using both Cisco Jabber and UCCX for our contact center. We got a few users reporting they get randomly the calls with dead air. All the customer support calls were getting routed through UCCX to the Jabber. All agents takes calls through Jabber.

I have done audio drivers update, switched the internet provider, tried with Cisco VPN and Zscaler and did with reinstallation of the Cisco Jabber profiles. Still the users reporting dead air in the calls. Checked with cisco tac and they told its a network related issue and asked us to check the network connectivity. If thats the case then all users should impacted. May I know what are the things to be checked network related?

Can any one of guide me?-

-Chandru

[Brad Magnani]

What version of Jabber are you running?  There's a known Jabber bug on 14.1.0 for the symptoms you're stating, which may be what you're hitting: 

Jabber audio drops during active calls
https://bst.cloudapps.cisco.com/bugsearch/bug/CSCwb35237

Symptom: Jabber Windows 14.1.0. Calls are established and audio will drop to one-way and periodically return, then drop out again. Issue is intermittent and a hold/resume brings the audio back two-way. The network is 100% stable with no drops, the audio processing issue is internal to Jabber after receiving audio on the wire. Network captures and local Jabber raw audio captures show it's a Jabber audio processing issue.
Conditions: Jabber Windows 14.1.0
Workaround:
Further Problem Description: Fixed. Applies to Jabber Windows/Mac/JVDI 14.1(1) and Jabber Android 14.1(2)

[lyndon_s87]

To confirm, the dead air, is the person calling into UCCX able to hear the agent on Jabber? Or is there no audio in either direction?

Something that would be worth checking is your firewall(s). You could be hitting the bug Brad suggested, but also would be worth checking your firewalls to ensure that SIP ALG isn't causing you problems (recommend to disable it for voice as if can cause reliability issues), and that you're not seeing any denies/drops for RTP in either direction.

[Elliot Dierksen]

Also Jabber supports some codecs that most ITSP's do not. I would suggest making sure you have CDR and CMR enabled on all CM nodes. Then check the CDR/CMR info when a problem call occurs. If you get notified quickly enough, you can check the CM logs or SIP traces.

[chandru_bbc]

Hi Elliot

I checked both CDR and CMR, there I found the Originator Cause code is 16 and destination Cause code is 0.

Latency-null, packets send & received -Null Latency-- Null, What you will inspect from this CDR/CMR data?

[chandru_bbc]

The agent is not able to hear the external customer voice. Its a dead air. If the agent press Hold and resume, then the agent is able to hear external customer voice, without any issue. We are using Jabber 14.1.5.57909. So I am not hitting the Bug as per your Brad right? Also I took packet capture traces and not seeing any RTP traffic in that. Since its a randomly occurring not able to identify the issue.

[VoIP Engineer]

Most of the time when I see one way audio, it's a network / routing issue.  Firewall is another possible culprit. 

I would start by looking at the CDRs to see what the phones are reporting (VoIP Detective is a good free tool for this).  Are the complaining users all in one location?  All offsite?  You can also use RTMT to monitor your transcoders and MTP if those are in use (they could be running out).

It may sound silly, but I had this exact same scenario happen, and it was "agent error".  The queue was set to auto answer, and the agent would step away.  The caller would just hear dead air, and they would beat up us telecom guys about this "perceived technical problem".

[chandru_bbc]

Still we are having issue, collected the packet capture logs from the users machine but we didnt see any RTP traffic. The external callers couldnt hearing our agents voice, then the agent some times drops the call or press hold + unhold key in jabber to hear the customers voice. The agent presses hold+unhold key to continue the call hearing. Now the issue is occurring to many of our agents.I  listened one of our call recording , there I noticied agent couldnt hear the cutsomers voice. What are the ckecks can be made?

[Elliot Dierksen]

I think you should focus on the control traffic. Based on what you have said, you won't see RTP packets. You need to see where control traffic is being missed or look at firewall deny events when the attempt is made to open the RTP stream.

[Nithin Eluvathingal]

Your symptoms match the bug @brad mentioned. Try upgrading Jabber to a different version to see if it resolves the issue.

2.12.0.0

[Scott Leport]

Hi,

At what point in the call do your agents / callers hear dead air? Is it consistently at the same time in the call, such as 15-30 mins or is it any time? 

[Alexis Amaro]

I have seen similar issues when recording is enabled and Jabber attempts to negotiate OPUS.

Most recorders do not like OPUS, check "OPUS Codec Enabled" In the Cisco CallManager Service Parameters, you might want to have it set to "Enabled for All Devices Except Recording-Enabled Devices".