No Subject

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
jdrosen@dynamicsoft.com                     FAX:   (973) 952-5050
http://www.jdrosen.net                      PHONE: (973) 952-5000
http://www.dynamicsoft.com

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