Hi,
Assume a UA sends a SIP INVITE, with an SDP offer that contains a number of different alternatives/configuratoins, using CapNeg mechanism(s).
Now, the INVITE is forked to a number of terminating UAs.
The terminating UEs send back 18x responses with SDP answers, where there different terminating UAs chooses DIFFERENT alternatives/configurations.
Now, what does the originating UA do?
Does the originatin UA have to simulatnously reserve resources for, and be able to support, ALL of the chosen alternatives/configurations, until it knows from which of the terminating UAs it will receive 200 (at that point it can release all resources associted with the other terminating UAs)?
And, of course intermediates will have the same problem: even if they support CapNeg, they may end up having to support multiple alternatives/configurations simultanously.
Of course, and could say that we can have the same problem even without CapNeg, if the terminating UAs indicate different codecs etc in the SDP answers. But, with CapNeg one can give much "broader" alternatives, so it may be much more difficult to deal with SDP answers indicating different alternatives.
So, do we need to say something about it?
I know MMUSIC doesn't deal with SIP, but I think we all agree that SIP will be the main (only?) "customer" of CapNeg.
Regards,
Christer
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