One of the things call centers supervisors really like to do is listen in on agent calls.  I’m sure it’s not *just* because they are nosy-type people, [insert business justification here], so part of my job is to make sure their eavesdropping is configured and working properly in Cisco Contact Center Express (UCCX).

Now there are about 11 ways to Sunday monitoring and recording can be jacked up by various elements, not the least of these being the voice engineer at the configuration helm. So when, during a deployment, it was found that calls were not able to be monitored or recorded, I skipped right past the look of surprise and moved straight into the what-is-it-this-time expression.

First, the symptoms.  Agents were getting calls and their supervisors were recording these calls. This means a whole bunch of agent/supervisor/phone setup tasks were completed correctly. Plus one point to the competent voice engineer with the mad skills. The recorded files were then being played back, however, and the tracks contained no audio.  Minus one point to the slightly less competent voice engineer who may, in fact, just be mad.

This not being my first rodeo, I initially suspect a codec issue, quickly confirmed by using the question mark button on the phones when the calls are made.  The display on the phone shows me the codec the calls are using is g.722 which, while a lovely codec, is not actually supported by UCCX.  It having been a long day, I decide to take a hatchet to g.722 and disable it in the Call Manager system wide parameters – ensuring no more g.722 EVER. Or at least not in this cluster.

Fully expecting the new rounds of tests to be successful, I get to use my surprised look after all when, once again, the recorded tracks lack audio. Grrr.

Firing up trusty Wireshark shows something very interesting – there is no RTP traffic from the PC to the UCCX server. For those who don’t eat, sleep, breath voice, RTP is the transport for the audio portion of the call.  All the setup/control messages will generally use SCCP, SIP, or H323, but the packetized voice uses RTP over UDP. The fact that it is completely absent from my capture file is more than a bit disconcerting.

After a nice talk with my buddies at TAC, they inform me that this is commonly seen with the particular brand of antivirus being run on the client workstations. After uninstalling the antivirus product and running the capture file again, RTP packets make an appearance and victory is declared in my favor.  100 points to the cheeky voice engineer from Dallas.

In case you were wondering what this RTP traffic looks like in Wireshark, you are looking for something like this:

As an added bonus for making it to the end of this post, here are a few other things you should check on the phone device configuration page in Call Manager when having issues with recording and monitoring, they are pulled from this document: Cisco CAD Troubleshooting Guide CAD 8.0 for Cisco Unified Contact Center Express Release 8.0 Cisco Unified Communications Manager Edition revised April 2011

• PC Port—Enabled. If the PC Port is not enabled, the agent PC that is connected to the port will not have network access. No voice streams will be seen by the desktop monitor module
• PC Voice VLAN Access—Enabled. If the PC Voice VLAN Access is not enabled, no voice streams will be seen by the desktop if the desktop is not a member of the same VLAN as the phone.
• Span to PC Port—Enabled. If the Span to PC Port is not enabled, the voice streams seen by the phone will not be seen by the desktop monitor module.