funpig,

I did a tethereal and fired it off to the Maemo developers. They confirm that there is nothing strange in the SIP communication going on. Asterisk sends a REGISTER with a media description, N900 answers TRYING, RINGING and then issues the Internal Server Error.

I did debug the sofia-sip stack. It complains "nua_set_params(): failed: Error Setting SOA Parameters" before it issues the Internal Server Error. Looking in the code, this seems to be right after it has figured out all the media stuff. I have tried on Asterisk 1.4 as well, but it is the same deal there.

It could very well be that there is one media option in the SIP negotiation that i causing this. I don't know what it could be though. For sure there is never a single RTP package sent