(Resolved) What does 'force registration' mean?

[Mango]

Some users have reported problems with one-way audio. Sometimes the problem is worked around by using a STUN server or configuring Handle VIA Received et al. The typical response from Fongo Support is that they "force registration" which solves the problem. I have not heard this term before.

1) What is the technical definition of "force registration" and how does one do it on a SIP switch?
2) Why do the workarounds work?
3) Can this be done for all accounts en masse? Or does it cause some side effect that makes this impractical?

Thanks to anyone who can answer any of the questions.

EDIT: Please see the thread http://forum.fongo.com/viewtopic.php?f=8&t=17074 which explains the behaviour in much more detail.

[Mango]

Removed.