SNMP for reachable SIP phones


I think I’ve seen this before, but after hours of searching these forums and Google, I can’t seem to turn up anything valid. I have SNMP working in Asterisk and can see everything as expected in the Asterisk (& Digium) MIB’s. Unfortunately there are a few things that I don’t see that I would like to monitor.

The biggest thing that I see that is missing is the ability to monitor the number of reachable SIP phones. It would be nice to know if 10% of my phones or 100% of my phones have gone offline, even if everything else is looking normal. In Switchvox this can be monitored via:
. number of reachable SIP phones

Is there any way to summarize in an integer this data in Asterisk?

The other thing that I was hoping to monitor would be number of active calls per trunk. Any insight in being able to do this would be great too.

In case it matters, I’m running Asterisk 11 from the AsteriskNow distro.