After the VoIP problems we had last year that prevented us from being able to transfer calls in the office after an update to the router from Virgin Media I knew I was in for an interesting morning troubleshooting a new problem, this time with the audio on calls skipping just enough to be annoying for us and very annoying for customers calling us.
For a while now the problem has been increasing, initially we though it was down to our internal hardware (our office network has a lot of devices connected to it) but after stripping everything out and reorganising things following the replacement of the floor in the office last week the problem just seemed to be getting worse. I finally tested with only the cable modem/router and one of our IP phones (a Linksys SPA941 for anyone who's interested!) and the problem was still apparent.
So, to cut a long story short, after a few hours of testing I finally tried a simple "ping" to the router, and low an behold there were latency spikes (of between 340ms and 1500ms) – there was no way that there would be enough legitimate traffic on the network to cause that, and just to make sure I tested with a ping to one of our internal servers. The result, the expected response time of <1ms.
So the Super Hub was doing something that was causing (comparatively) massive latency, that in turn was causing the audio on our calls to drop out periodically and was likely the cause of some other annoying glitches when accessing websites and causing SSH sessions to drop for no apparent reason.
My next step was to re-start the router and I've now been sat writing this post with a ping to the router running and the response times have been <1ms (as expected) for the last 15 minutes (and that's while streaming music with Spotify, downloading emails, and uploading some artwork to a drop box for a client.
So now it's going to be a case of monitoring the latency to the router and seeing if I can see anything that would cause it – although I don't think this has resolved the issue – the Super Hub must be doing something that causes the latency to rise over a period of time – if it's over a 24 hour period the easy fix will be to connect the router to a timer switch that will effectivly restart the router at 5am every day giving us (hopefully) a full day without issues.
We shall see and I'll make a follow up post if and when I find out anything more.