Subject: RE: [Sip] MUST 200 OK contain SDP?

From: Jonathan Rosenberg <[email-masked]>
Date: Thu, 30 Aug 2001 23:52:50 -0400

> -----Original Message-----
> From: Christer Holmberg [mailto:[email-masked]]
> Sent: Thursday, August 30, 2001 3:19 PM
> To: Juha Heinanen
> Cc: [email-masked]
> Subject: Re: [Sip] MUST 200 OK contain SDP?
> 
> 
> 
> True.
> 
> Christer (lmfchh)
> 
> Juha Heinanen wrote:
> > 
> > Christer Holmberg writes:
> > 
> >  > The spec is correct - the 2xx MUST contain a session description.
> > 
> > the spec is not correct before the word MUST appears in the the 2xx
> > sentence.
> > 
> > -- juha
> 

Well, the wording since bis-03 at least is crystal clear in this regard.
From Appendix B:

The usage of SDP within SIP follows an "offer-answer" model. One side offers
an SDP that provides their
view of the session, and the other side answers the SDP with a matching one.
The offer-answer model MAY
occur in two ways. The offer MAY be placed in an INVITE, in which case the
the answer MUST be in a 200
class response, and the ACK MUST NOT contain SDP. Or, the INVITE MAY contain
no SDP, in which case
the offer MUST be in the 200 class response, and the ACK MUST contain the
answer.

Thats pretty darn clear. Both of the two allowed conditions have a MUST for
the 2xx to contain SDP. I will fix the inconsistency with section 12.1.

In any case, since 18x is optional and not even reliable, it would make no
sense to just "skip" the SDP in the 2xx because it was sent in the 1xx. 

-Jonathan R.

---
Jonathan D. Rosenberg, Ph.D.                72 Eagle Rock Ave.
Chief Scientist                             First Floor
dynamicsoft                                 East Hanover, NJ 07936
[email-masked]                     FAX:   (973) 952-5050
http://www.jdrosen.net                      PHONE: (973) 952-5000
http://www.dynamicsoft.com

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