Re: [MMUSIC] AD Review: draft-ietf-mmusic-t140-usage-data-channel

[Christer Holmberg <[e-mail]>]

Hi,

...
    
    >> sdpneg has the following wording in 6.2 for the error case when both 
    >> parameters are included in the answer:
    >> 
    >>    "If an SDP answer contains both
    >>     of these parameters then the offerer MUST treat the associated SDP
    >>     offer/answer as failed."
    >
    > The tricky part of treating the O/A as having failed is that only the 
    > offerer knows this, while the answerer thinks it has succeeded. So the 
    > two sides have differing understandings of the state of the session. 
    > (Consider that there may also have been changes in another media 
    > section.) Things will not go well until this is corrected.
    >
    > I don't know if there is any document that specifies what to do in this 
    > situation. I think there are only two generic possibilities: drop the 
    > entire session (i.e., BYE), or start another O/A to try to fix this, 
    > perhaps by dropping the m= line. When following this latter course, 
    > there will be an extended period while the two sides are in 
    > disagreement, and no guarantee that the fix will work.
    >
    > The simplest solution is to simply say that this is a protocol 
    > violation, and recovery is an implementation issue. While simple to 
    > write, this is perhaps not the best solution.

That is normally what we say.

However, if more text is needed I think it belongs to the data channel sdpneg draft. I don't think that each data channel usage draft shall have to describe how it is done.

Regards,

Christer