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.
pjsip blog 
You did not mention documentation. The other sip stacks mentioned do not have nearly the same extensive documentation that PJSIP has.
Thanks Jon for mentioning documentation! That ties in neatly to support as provided through the mailing list, for cases when even the documentation cannot help you. We’ve also recently introduced wiki (via trac), although we are still exploring the best use of all these media.
You guys are Woz’s you need a Jobs. You should really hire a marketing/PR type to do the talking. I think you are selling PJSIP short and could have at least touted it’s small footprint targeted at firmware, smartphones, embedded devices, etc. You need to find all opportunities to stand out from the rest of the pack.
I’m sure there are many other benefits, but you really did nothing for the PJSIP cause. It may well be worth the time to do a thorough comparison between PJSIP and competing products. This will also help you to better understand what features/capabilities are needed and where to go next.
You might not see PJSIP efforts as a competition, but in fact it is. And the most utilized SIP stack will survive and the others will just be annoyances to maintain with it’s hold-out users that recognize that it’s the Beta of SIP stacks.
Motivated? 😉
Darron, I understand the analogy but I don’t think Steve Woz would be flattered to be compared with me!
As for the comparison effort, I personally never trust a vendor’s own or even “funded” reviews. Therefore we will just have to wait until somebody (other than us), somewhere, draws up some criteria and pitch several embedded SIP and media SDK together.
Personally I don’t like the new pjsip’s license. All the sip you have mention above were licensed under MPL or LGPL. But after all, you must have a good reason to license it under GPL :).
Performance figure is great.
PJSIP is “THE BEST” in performance.
@Rizki:
All the reasons for GPL has been argued by Richard Stallman of course 😉
More recently, Eben Moglen’s speeches, especially GPLv3 gave very convincing arguments. Check them out!
@Name123:
Thank you for the endorsement in performance. If you want to email me more details on your performance figures, maybe I can do a post about it.
pjsip is realy great, but priority in sdk(s) is fix bugs , not release new and new features with same bugs. But, its only my point of view… god job
@ed:
We agree, fixing bugs is so important. That is why you can see “bugs fixed” on this blog (see right hand sidebar, lower area).
PJSIP is great!!!
I like it very much.