Alex Balashov wrote:
This is extremely unlikely, unless they inherited one via licensing from an acquisition.
Developing a SIP stack is a surprisingly capital-intensive endeavour, at least, when it comes to working out interop issues and bugs, as well as natural race conditions arising from a literal interpretation of RFC 3261. All that testing and R&D is hard to afford. That's why the only good SIP stacks have been around for at least ten years (though, from this it does not follow that just because a SIP stack has been around for ten years means it's any good).
I wouldn't say it's trivial to do it, but one of our partners has a 100% custom-written and RFC-compliant stack and softphone which goes to great lengths to penetrate any NAT--they guarantee it. Licensing starts at $42,000, however for a company the size of Packet 8 that would be trivial. -- Carlos Alvarez TelEvolve 602-889-3003