I'm just wondering where the actual NAT piercing takes place in the SIP communicator code. I can see where you're using STUN to get a public address, but where do you maintain those port bindings with periodic outgoing UDP messages to make sure the NAT stays open to incoming traffic? Is that what you do, or do you take care of this somehow when the session is first established, alloing the RTP flow to keep the binding open once you're transfering media, something like that??
Thanks very much.