Hello,
I have read through your project description, I feel confident I can help you diagnose your SIP traces to identify causes of call dropping, and routing issues, along with any other potential issues with call signalling and/or voice.
I have been working in the Telecoms industry for the last 12 years, and have worked with and consulted some of UK's top telecom operators. I have been working with Asterisk, FreeSWITCH & Kamailio for many years in different settings.
I look forward to hearing from you.
Kind regards,
Adnan