30 second VoIP/SIP call drops

An edited copy of an email I just sent regarding calls dropping at 30 seconds, sometimes.

Re: 30 second call drop issue:

It's a common bug in some older commodity routers that all borrowed the same core firmware years ago. We don't see it as often as we used to, but we still do. You've got a good router on that site, I doubt that's got that glitch, but that's why we start there. Worth knowing, that problem is consistent if it exists, every call, at exactly 30 seconds (maybe 32).

Other devices will drop a call at about 30 seconds, for different reasons, intermittently. WiFi AP's especially if the phones are WiFi. They sometimes have connection tracking limits or are just overloaded. Then there are two things that just completely futz up a network we run into: Sonos WiFi speakers and Mesh WiFi repeaters (Orbi, Google Mesh AP). The WiFi meshes and repeaters often cause “loops” and break all connections and reset for just a moment when they do, or the ethernet switch involved detects the loop and resets.

I'd start with the basics and work up:

Do calls from 1 extension onsite to another break at 30 seconds? If so, that path/traffic is from phone to hello Hub to phone. I'd look at local networking gear. Maybe even a specific phone or ethernet connection.

If that's OK, is it calls to/from landlines (POTS or VoIP) or mobiles? Just one call, or do all calls happening at the same time drop? If all, something upstream from the Hello Hub is breaking the connection: ethernet switch→router→modem→ISP's gear….

I checked out his system last night while checking a problem with fax connections. It looked good but I noticed it was missing some audio prompts when I made test calls (002 and 000) so I sent it an updated sound files (a zip). Transfer speed was < 400KB/s. Took over 10 minutes to transfer. I just did it to my home system, sent 252MB in 8 seconds… 28MB/S – This is probably an indicator of not a great ISP/network connection at . I'd be curious to know what kind of speeds to get from a speed test and what you are paying your ISP for. This was about 10:30pm last night, in case that helps. Maybe you were doing a massive backup/download?

And to test again: I called this morning, two-way audio test ( dial 002 ) sounded great, and I also listened to hold music for about 3 minutes, also sounded great. I also just sent the sounds.zip (252MB) to the system and it took 30 seconds, at 8MB/s. - That's a big difference from last night. is there something variable in the network.ISP, or behavior (downloads, etc..). Maybe that's a clue?

In summary: I'd start with logging the 30 second call problem: What phone, to/from what caller. My assumption is they are outside callers. Are they calling while driving down the road? Or are these solid calls to a fixed location that drop. How was the audio quality of the call before the drop?

Diving into deep diagnostics mode: With the external phone numbers involved and an approximate time and if I get it within 48 hours, I can grab switch logs and see which end dropped the call. If the other parties are dropping, not much I can do but identify it. If the Hello Hub side drops the call, it may be something we can find and address.

–Mike–