Lose audio on computer reboot

Last week I was working on a colleague's iMac while she was talking on her Cisco phone. The iMac suddenly shut down and she lost audio on the phone. The phone didn't lose its connection but neither party could hear the other. 

So I ran some tests. Her iMac's network connect is through her phone. To my surprise every time the iMac shut down or started up the phone would lose all audio. Was the iMac sending a storm of packets, overwhelming the phone's routing function? It was time to call my CWPS for phone support.

The tech noticed that Quality of Service (QoS) was not turned on at the switch. He suspects that the iMac creates so many packets on startup that it overwhelm's the voice traffic and that turning on QoS should solve the problem.  I will test the computer and phone this week to see if QoS solves this problem and/or results in any other changes for my colleague.