Subject: [MMUSIC] SDPCapNeg version 06 is here

From: Flemming Andreasen <[email-masked]>
Date: Tue, 10 Jul 2007 16:33:49 -0400

The -06 version of the SDP Capability Negotiation document is now 
available at 
http://www.ietf.org/internet-drafts/draft-ietf-mmusic-sdp-capability-negotiation-06.txt

I appreciate all the feedback and comments provided on the -05 version 
and I believe this version addresses all of those as discussed in Prague 
and subsequently on the mailing list. At this point, I am not aware of 
any open issues and hence believe we should be ready to issue a Working 
Group Last Call.

The changes in the -06 version are (from Section 8.1):

        o  Added additional background text on terminology used, and a 
new section on the negotiation model. 

        o  Allowed for session-level attribute capabilities to contain 
media-level only attributes, albeit the base framework does not define 
(or allow) them to be used in a potential configuration
           (extensions may change that)

        o  Disallowing multiple "a=tcap" attributes at the session-level 
and/or on a per media description basis; at most one at the 
session-level and per media description now.

        o  Changed the "a=pcfg" attribute to make a potential 
configuration list optional in order to allow for the actual 
configuration to be referenced. 

        o  Removed the ability to delete and replace individual 
attributes from the actual configuration SDP. 

        o  Introduced the notion of mandatory and optional attribute 
capabilities in a potential configuration and updated the "a=pcfg" 
attribute and associated procedures accordingly. 

        o  Specified that mandatory attribute capabilities and the 
transport protocol (if any) from a potential configuration need to be 
supported in order to select that potential configuration.
           Offer/answer procedures updated accordingly as well. 

        o  Noted potential interaction and synchronization issues with 
use of session-level attributes and attribute capabilities and added 
recommendation to avoid use of session-level attributes when
           possible.

        o  Fixed error in "a=acfg" grammar (missing config-number) and 
updated attribute definition in accordance with the "a=pcfg" attribute 
changes. 

        o  Updated text associated with processing media before answer 
to allow for playing out garbage or discard until answer received. 
Additional detail on alternative solutions provided as well.

        o  Added recommendation to send back answer SDP as soon as 
possible, when a potential configuration different from the actual 
configuration has been chosen. 

        o  Added new section on interactions with SIP option tags.

        o  Added new section on dealing with large number of potential 
configurations.

        o  Added new section on SDP capability negotiation and 
intermediaries. 

        o  Updated examples in accordance with other changes and to 
illustrate use of mandatory and optional attribute capabilities in a 
potential configuration. 

        o  Updated security considerations to address potential denial 
of service attack caused by large number of potential configurations. 

        o  Various editorial updates throughout.

Please let me know if you have any questions, comments, feedback, etc.

Thanks

-- Flemming

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