I'm looking for a SIP stack to use on the Android platform. Since it's for a client, to be used for commercial purposes, GPL'ed stacks are not feasible.
What would you recommend, SO?
As of Gingerbread, a SIP stack is built right into the API, in the android.net.sip package.
There's some demo code that shows how to use it here.
You can use the JAIN SIP Stack, it should run out of the box. I did try it 1-2 years ago See my blog post with an example about it http://jeanderuelle.blogspot.com/2008/10/jain-sip-is-working-on-top-of-android.html
RADVISION, the company I work for, also offers a SIP stack solution with a commercial license that is suitable for Android: http://www.radvision.com/Products/Developer/VoIP-Developer-Tools/SIP/default.htm There are other Android related SIP solutions as well, but this is the "general purpose" one.
Alexander Lucas mentioned the Android SIP stack. There's a review of it here that points out a few missing items: http://www.onsip.com/blog/leo/2011/01/05/our-evaluation-of-android-gingerbreads-native-sip-calling-with-the-nexus-s
A couple of other things to consider are that the phones supplied by carriers may have the SIP stack blocked or crippled, and that the Android SIP stack is not available on the iPhone or other devices. Many commercial stacks are available ported to Android, iPhone, Symbian, Win7, etc so if you develop for several platforms, your job is easier
I recommend TeleSoft CompactSIP. And I believe in it so much, I chose to sell it. See http://www.telesoft-intl.com/DS_Android.html
来源：https://stackoverflow.com/questions/4007860/looking-for-a-sip-stack-for-android