Re: [MMUSIC] POF/PAN: Length of mid values

[Paul Kyzivat <[e-mail]>]

On 10/22/13 6:31 PM, Martin Thomson wrote:
> On 22 October 2013 11:12, Christer Holmberg
> <[e-mail]> wrote:
>> Wouldn't it be possible to simply assign e.g. a 1 character mid value prefix
>> to the Offerer and the Answerer?
>
> That would be possible iff you could derive that from the original
> context consistently, but I'm not sure that this is possible in SIP
> given 3PCC and all the crazy shit that goes on there.

I thought about that too.

We *could* say that if there is a middle box that turns offers into 
answers, it also has to fix up the resulting mess. It would, in 
principle, know enough to do it. Boxes that do that already have to fix 
up other stuff.

Or we could define an O/A negotiation for the prefixes. That would still 
require a middle box to do some fixup, but it would be simpler.

Or, as I suggested earlier, we could derive a prefix from other stuff in 
the offer and answer that is likely to result in unique prefixes for the 
two sides. And just ban POF/PAN if it doesn't. (In that case another O/A 
could probably resolve it.)

	Thanks,
	Paul