One of the questions we get asked a lot is “How does pjsip compares to other SIP implementations?” This would include reSIProcate, Sofia-SIP, OpenSIPStack among others. We have a few more on our links section. Apparently a few other people have also attempted to do comparison of open source SIP implementations, such as Martin van den Berg [PDF file]
The short answer is: We don’t know. Sorry.
The not-so-short answer is: It depends (otherwise known as the software engineer’s cop-out).
We could point out pjsip’s very small footprint, but if it’s going to be deployed on a multi-core system with gigabytes of space, “who cares.”
Or what about the availability of pjmedia, giving a top-to-bottom solution without integration headaches? “Don’t need it, our platform does them all in hardware, thank you very much.”
Or the fact that the same pjsip API can run from the smallest and most barren of platforms (sockets? what are those?) to the aforementioned oodles of RAM multi-core PC with an OS the size of a house. “We’ll pass on that… our solution only requires one end of that long stretch!”
So we can’t really say how pjsip compares, because there will always be different requirements for each application project. As it happens, selecting components for your next killer application is still an inexact art science. Lots of trial and error, and sometimes you just have to close your eyes, take a deep breath and jump in.