I was wondering today what RTC stacks I've used in all these years and I though it would be interesting to remember them because somehow you can see the evolution of communications through them. This is the approximate timeline (I'm sure I'm forgetting some):
2006 NIST SIP Stack
2004 In house developed SIP Stack
2000 NetMeeting ActiveX
With a couple of
exceptions I have always favored the usage of opensource stacks because
they have always been very compelling and mostly because it is a lot of
fun the possibility to hack them.
There are much more stacks that I've used for prototypes or Hello Worlds and were also great but this list only includes the ones used in commercial projects.