Random dropped calls

I am trying to diagnose and resolve a problem with calls in progress to my office getting dropped.

We are running Asterisk, with FreePBX 2.9.0, a SIP trunk, and the licensed G.729 (I think that’s the one?) codec installed to help trim down bandwidth.

The problems that we’ve run into is either where people calling in stop hearing the office side, but the office workers can still hear the inbound callers just fine before it drops. Then there’s the occasional ‘all lines are busy’ errors when trying to dial out for anybody in the office.

I’ve been doing Linux administration for over a decade now but I’m still a beginner at VOIP and associated technologies (that usually has a whole department of its own), but this is in my lap and the disruption to work is really hurting the office workflow.

What can I look for to determine whether the problem is the VOIP box, the internet provider (by way of poor connection), or bandwidth needs? What key words can I start digging through the logs with in order to FIND the dropped calls and start getting meaningful diagnostic information from them?

You are not going to find anything in the log. Do you have any type of QoS?

I would monitor bandwidth (does your router support SNMP, if so Paessler PRTG is a good free tool) and see if you see a correlation.

The log will have nothing? That blows me away, but I’ll stop digging through it then I guess. As for the router and QoS, I’m not sure. It’s a (very) small business setup, I know the VOIP server has its own public IP away from the rest of office’s internet but I don’t know if that runs over the same modem to the provider or not. I’ll see it in person when I go in this morning and be able to report on that front.