SIP Invite problem


#1

Hi all you guys,
I’m trying to persuade my company to move to Asterisk as PBX, SIP and VoIP server. I’m testing SIP capabilies by a self-make Symbian SIP application running on emulator and a java application running on another pc inside the LAN. Registration procedure is correctly done, Invide isn’t and here is the Asterisk error message: “Unknown SDP media type in offer: application 0 tcp Controller” where Controller is my SIP application name.
How can I solve that?

Thanks,
Giovanni

P.S.: my application works perfectly using Nokia Sip Server Emularor.


#2

Not sure, but I remember that Nokya emulator uses the AMR codec that is not supported by asterisk;

C.


#3

[quote=“spyke”]Not sure, but I remember that Nokya emulator uses the AMR codec that is not supported by asterisk;

C.[/quote]

Hi mate,
thanks for your reply. My application code is not compiled using ARM, anyway, it uses standard SIP API. Frankly speaking I think the issue is about that “application” inside the m SDP parameter. Unfortunately I did not find anything about that use of m parameter, every search has found a RTP usage only. What do you think about?

Cheers,
Giovanni


#4

Which codecs are supported by your application?
Try to use another UA tha support the same codec, sniff with ethereal and look the SDP body for the ‘m’ field;
It is as the one your application sends?

C.


#5

[quote=“spyke”]Which codecs are supported by your application?
Try to use another UA tha support the same codec, sniff with ethereal and look the SDP body for the ‘m’ field;
It is as the one your application sends?

C.[/quote]

My application uses SIP only to know IP address of a phone (using the INVITE) then it usually open a socket for a peer-to-peer data comunication (nor audio or video) so the only “codec” I have to use is “application” in m SDP parameter.

Giovanni


#6

I think you will find that your problem is because Asterisk does not parse unknown application types. Asterisk is a PBX, not a SIP proxy per se. It wants to know what the uac is asking for as it intervenes in the process to apply policy, etc. If it does not understand, or support the media type it will probably reject the request. I had this issue last year when I wanted to use T.38. As Asterisk did not support T.38, it would not pass the INVITE on to the UAS. I think this is still the case.