[cweagans]

FWIW, I went down this road a few years ago. If I were you, I'd seriously consider rescoping your project. Asterisk is a beast, but it is capable of doing everything you want. If the problem you're trying to solve is that Asterisk is a pain to install, configure, and administer, why not solve that problem? An easy way to install Asterisk + a nice control panel on top of it would be really appealing to a lot of people.

[zackify]

Because that wouldn't solve half the problems and some things just aren't possible. Building off existing open source phone solutions is like asking a team to continue building on top of garbage code, have you looked at the FreePBX repos on github? I don't understand how you could ever extend it

[cweagans]

FreePBX is not great, but I'm not saying that you should use it. I'm saying that you should use Asterisk, which is what FreePBX is built on top of.

Asterisk is really, really solid, and will handle a lot of things for you that you shouldn't have to care about handling - lower level stuff.

Check this out: http://www.igorescobar.com/blog/2014/08/13/working-with-aste...

If you're going through the SIP RFCs for what you want, you're attacking the problem at the wrong layer of the stack. It's just not necessary to write your own SIP stack. It'd be like writing SSL negotiation logic for a web app: totally pointless. Just use what already works and extend it with the fancy UI and dev experience that you want. It's totally possible.