[VoiceOps] SIP calls that aren't torn down

Over the last few months our softswitch has accumulated 10 "stuck" calls where there's no media traffic. From what the softswitch vendor can tell or guess, it just didn't receive a BYE to tear down the call. We know that most SIP traffic on 5060 is UDP, and UDP is connectionless. How are other vendors and systems managing such scenarios? I suggested a "no media" test where after x hours of no media, to tear down the call and log the info. Thoughts? Frank