[SR-Users] Tracking ITSP Trunk Utilization

Greetings, I have a challenge which I can't imagine is unique to my situation. I have agreements with multiple ITSP/SIP providers for inbound and outbound use cases. I am trying to figure out a way to track and monitor - on a per trunk basis - statistics about open dialogs. In the end, I would like to have nice graphs that show my usage throughout the day... and most importantly, my max open dialogs so I can determine if I am coming close to my max sessions with any particular carrier. Does anyone know of a tool which could help me track this? It looks like Kamailio has some SNMP modules, perhaps SNMP + Cacti might be the common solution? Any input is greatly appreciated. Thanks.