I am working on a android application in which i have to implement peer to peer voice chat. I found in android this is possible in API level 12 or above because Google added android.net.rtp
package in API level 12. By using this package we can implement peer to peer voice chat and video chat. But I need to implement this for API level 8. Now my questions are:
I suggest have a look at PJSIP opensource SIP stack. It isn't officially ported to Android, but some people have succeeded in using it on Android and have posted patches too.
http://trac.pjsip.org/repos/wiki/Getting-Started/Android
The "csipsimple" project seems to be under active development.
http://sipdroid.org/ might be helpful too.
HTH