RE: [Sip-implementors] MSN Messenger call problem

[Kedar Patil]

As Antonis explained, Windows Messenger may not do two medias
of the same payload-type. Fine.

 

Now coming to your new concern that Windows Messenger responds
with two options again (PCMU, PCMA):

 

As per RFC 3264, UAS is free to answer with multiple payload types.

(But I wonder why would they choose to do so?). It would have been better if

it had replied with one payload-type.

 

However, UAC has one more chance to select its preferred payload-type

(most prob. the first one of those listed in 200 resp.) with the SIP ACK message.

 

thanks,
= Kedar =

-----Original Message-----
From: Paraskevopoulos Pavlos [mailto:[EMAIL PROTECTED]]
Sent: Thursday, December 19, 2002 5:05 AM
To: Kedar Patil; sip-implementors
Subject: Re: [Sip-implementors] MSN Messenger call problem

Hi again,

I am afraid you didn't understand what the problem is...

So,

When I' m sending the media Description in multiple lines    
Media Description, name and address (m): audio 2074 RTP/AVP 0
Media Description, name and address (m): audio 2074 RTP/AVP 8

the messenger (you can see from the trace) responds

1) m=audio 58772 RTP/AVP 0
   a=rtpmap:0 PCMU/8000

So this is a payload Type of "0" (G711ulaw) with an RTP port of 58772

AND

2) m=audio 0 RTP/AVP 0
And this is a Payload Type "0" (G711ulaw), also but with an RTP port of 0

Moreover there is only one machine.

However, changing my implementation, I am sending the Media Descriptors in one line, that means....

m=audio RTP/AVP 0 8

and it responds OK

m=audio 42634 RTP/AVP 0 8
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000

Is it something wrong or it's my idea.

Any advice will be appreciated.

Thanks.