Remember that GC is an over-the-internet cloud product and as such, it sometimes has issues outside of your control. You can test your WAN/LAN for QoS and other things, but once it reaches the Router, it is up to the internet. I suggest you look at the MOS scores on the calls, listen to the lower scores and try to determine on which side of the call the quality is poor. You can also use the WebRTC tools in Chrome to look at traffic, throughput, and other factors.
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Robert Wakefield-Carl
Avtex Solutions, LLC
Contact Center Innovation Architect
robertwc@avtex.comhttps://www.Avtex.comhttps://RobertWC.Blogspot.com------------------------------