First you will want to check the Managers Dashboard for Alerts and Notices. If nothing there then you will need to check the IP Service Levels. Find location and click on the IP address, another window will pop up and you want to check the Jitter, Lag and Loss. Now if these are high you will need to call the internet provider for that customer. When calling the internet provider make sure to go to Technical Support. Explain that we have a mutual customer and that when we check the network we are showing jitter or packet loss or whatever that you see you let the internet provider know. They will do there test and when those are done if they do find and issue and need to send someone out make sure to grab the ticket number from that so that you can log it on the ticket you made in our system that way if anyone else needs to work on that issue all the information is there. If it is not there issue and everything look fine then have them manually restart the phones and at that time if they are still having those issues please escalate to Tier 2.
For in-depth over view of extension