There are several software utilities one can use to troubleshoot voip issues and guage quality. Below are a list of some of the common ones.
apt-get install tcpdump
tcpdump -nq -s 0 -A -vvv -i eth0 port 5060
you can change the command to suite the proper ethernet device eth0 with what is on your system. Port 5060 can be changed also if you are using a different port.
Since March 2017 Sngrep is installed on all systems by default. This is a very useful tool to help troubleshoot all types of sip related issues.
If you installed FusionPBX prior to March 2017 you can still manually install sngrep.
Call Quality and Monitoring¶
Call quality can be a nucense in the voip world. Having a way to track and make reports are a very needed tool.
Homer is well known to help track and graph quality issues with SIP like utilizing QoS Reports.
HOMER is a robust, carrier-grade, scalable SIP Capture system and VoiP Monitoring Application offering HEP/EEP, IP Proto4 (IPIP) encapsulation & port mirroring/monitoring support right out of the box, ready to process & store insane amounts of signaling, logs and statistics with instant search, end-to-end analysis and drill-down capabilities for ITSPs, VoIP Providers and Trunk Suppliers using SIP signaling protocol.
To install and configure Homer visit https://github.com/sipcapture/homer