Hello Prasanna,

I believe your example just below is fine. I say this because rfc3261 says application/sdp bodies in 488 are to be the same as those in 200 responses to OPTIONS request. rfc3264 (referenced in rfc 3261 section 11.2) implies (in section 9) 200 responses to OPTIONS as you've indicated below. As you say, there is no explicit text in rfc3264 concerning responses to OPTIONS requests. However, I believe this behavior is intended. If we assume section 9 in rfc3264 titled "Indicating Capabilities" is the target of the reference in section 11.2 of rfc3261 (which describes OPTIONS response), then we have rfc text that specifies what you have shown.

Best regards,
Bert

Prasanna Venkatesh wrote:

Hi Bert,
    Part of the issue of capability indications was answered by Jonathan as per
the section .9. of RFC-3264.
The other part was that how shall a UA indicate the media capability if it
does not support any media codec which is offered.  This is answered as per
line 594 of RFC-3264.  However it is not explicit in the RFC if any
additional media formats which the UA supports can be set in the rejecting
answer.
Assuming direct RFC-1890 mappings,
Offer
INVITE ...
...
m=audio 23456 RTP/AVP 0 18 // G.711 PCMU & G.729
....

Answer
SIP/2.0 488 Not Acceptable
...
m=audio 0 RTP/AVP 8 //G.711 PCMA only supported


Is this fine?

Regards,
Prasanna

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Bert
Culpepper
Sent: Sunday, January 26, 2003 12:41 AM
To: Prasanna Venkatesh
Cc: Jade Chen Yan; [EMAIL PROTECTED]
Subject: Re: [Sip-implementors] accept header


Hi,

A UA indicates it doesn't support one or more of the media formats
received in an offer by omitting the payload type(s) not supported in
its answer (see section 6.1 in rfc3264).  It rejects a media type by
setting the port number to zero (see section 8.2 in rfc3264).  So for
your example, the offer will contain a media line in its SDP as:

m=audio 23456 RTP/AVP 96 97
...
m=video 23556 RTP/AVP 98

where "a=" lines (appearing after the corresponding "m=" line) map 96 &
97 to the G.723 & G.729 media formats and map 98 to the H.263 media
format.  The answerer will formulate its answer with media lines in its
SDP as:

m=audio 33222 RTP/AVP 96 99
...
m=video 0 RTP/AVP 98

where "a=" lines map 96 & 99 to the G.723 & g.711 media formats.

Regards,
Bert

Prasanna Venkatesh wrote:


Hi Jade,
This should be taken care by the offer - answer model.
The error code for INVITE is 488.  There can be a body in the 488

mentioning

the media capabilities supported.  But there are issues as the 488 is
hop-by-hop it can be dropped.  I am also not sure how to just denote the
capabilities in the SDP.

Regards,
Prasanna
-----Original Message-----
From: Jade Chen Yan [mailto:[EMAIL PROTECTED]]
Sent: Thursday, January 23, 2003 2:23 PM
To: 'Prasanna Venkatesh'
Subject: RE: [Sip-implementors] accept header


thank u for your reply.

But if the one UA cannot accept the media type eg , G.729 , it support the
G.711 & g.723, how can the UA tell the other party,?which header should be
used? the UA generate a 481 responsed which contains the sdp body?

regards,
Jade

-----Original Message-----
From: Prasanna Venkatesh [mailto:[EMAIL PROTECTED]]
Sent: Thursday, January 23, 2003 4:43 PM
To: jade(3???)
Subject: RE: [Sip-implementors] accept header


Accept is for the SIP bodies and not the media which is defined by the
bodies.
An example is
Accept: application/sdp, text/*, image/gif

The media codecs(g.729 / g.723 etc.) are defined by the sdp body.

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Jade Chen
Yan
Sent: Thursday, January 23, 2003 1:45 PM
To: Sip-Implementors (E-mail)
Subject: [Sip-implementors] accept header



hi, list,

Can any one give me an example for the accept header?eg, the ua accept the
g.723, g.729 & h.263 codec.

thanks.

Best Regards,
Jade



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