I have been using the Ooma Telo for VoIP phone service at home for several years. Over the last few months my wife has complained that she loses VPN connectivity to her corporate network when the phone rings. I had set up the home router with QOS for the Telo device and tried to adjust the settings available with the OpenWRT firmware to make sure the Telo was not getting all of the available bandwidth and creating the problem. That did not seem to help as the problem continued. So tonight I decided to troubleshoot the issue and ultimately found the problem and a solution.
To explain the solution I probably need to explain my network set up. The home router is running OpenWrt which is connected to the cable modem. The Ooma Telo device is connected to the LAN. This is not the recommended set up by Ooma. Ooma would like for the Telo device to be connected to the modem and the router connected to the Telo. I don’t want to do this as I think it would impact my ability to host this server on my network. In addition to the Access Point (AP) on the router, devices on the LAN are a couple of gigabit switches and two AP’s providing a point to point wireless bridge for wired connections to the stereo receiver, TV, Wii, etc.. Actual devices on the rest of the network are computers, phones, tablets and an Epson 845 WorkForce printer.
To troubleshoot, I set up a ping to an Internet host and called the home phone from my mobile and there was no impact to the ping. Then I started my work VPN (Cisco AnyConnect) and repeated the test, except this time I pinged an internal IP address on the corporate network. Sure enough, as soon as the home phone started ringing, my ping failed. Since the problem only started happening the last few months and the network was pretty stable up until that point, I started looking at other changes and the only thing that came to mind was connecting a phone line to the Epson printer a few months ago. So I disconnected the phone line to the printer and ran the VPN test again and the ping continued with no problem. So, for now, the printer is disconnected from the phone line and I believe this will prevent dropped VPN connections and keep the wife happy and hopefully help some others that might experience this problem.