How to measure quantity of concurrent calls and also the number of incomming messages to FreePBX?

hello people,

I’m new in the IP telephony, and I need to take the measure of some parameters about FreePBX.
This parameters are:
_quantity of concurrent calls
_Simultaneous voice incoming messages

Then I would like to know how can I do this?

I hope somebody can help me pls!

PS:Maybe some FreePBX module let me know those parameters measures.

Thank you, best regards!!!