This continues to be an issue. Unfortunately, troubleshooting is complicated because by the time I know there is a problem, my colleagues need to get to work. So, a modem reboot is the quickest way to work around the problem (but doesn't solve it).
I did have a packet capture set up and ready to go so I did that today. On the Shaw side, I saw the UDP audio traffic leaving, and I confirmed the IP and port numbers were valid. The remote side received zero packets.
A different device on my LAN that does SIP over UDP (instead of TCP/TLS) and connects to the same VoIP server remained registered the entire time.
tl;dr:
SIP over TCP: works
SIP over UDP: works
RTP over UDP: fails
Always after a weekend (but not every weekend).
Rebooting every piece of equipment except the modem does not change anything.
Modem reboot always solves the problem (temporarily).
I'm stumped.
