T Satyanarayana-A12694 wrote:
> Yes, I do agree that implementations have done a good job of working
> with this ambiguity so far. And, it is not as much an issue.
>
> However, I am having a difficulty to visualize a use case where the
> offerer may use this "addl codec" to send media. Even if the offerer is
> prepared to receive, the offerer would probably never use it (if he
> could, he would have declared it in offer anyway).
>
> So, wouldn't it help if we can add a qualifying statement to the spec:
To *what* spec? 3264?
It perhaps could have gone in the offeranswer draft, but that is
"finished" except for a little tidying up.
Thanks,
Paul
> "The answerer may add additional codecs in the answer. However, at the
> time of writing this spec, there are no known use cases warranting this
> condition."
> Regards
> Satya T
>
> -----Original Message-----
> From: Paul Kyzivat [mailto:[email protected]]
> Sent: Tuesday, August 18, 2009 7:53 PM
> To: T Satyanarayana-A12694
> Cc: Dale Worley; [email protected]
> Subject: Re: [Sip-implementors] Can EP send media only peer supports
>
> The more I think about this "issue" the less I understand why it should
> be an issue.
>
> The answerer is under no obligation to include codecs that were not
> present in the offer. And if it does so, there is no guarantee of
> circumstances under which they might be used. And the offerer is
> certainly free to ignore them.
>
> So the only question is:
>
> *If* the answer includes codecs that were not included in the offer, may
> the offerer use them to encode media? And that is only an issue if the
> answerer is *not* expecting them to be used.
>
> So, if you are constructing an answer, don't include any codecs that you
> aren't prepared to receive now. (If it hurts, don't do it.)
>
> All we could possibly do by tightening up the wording is ensure that
> even if mentioned, such codecs would not be used. What purpose would
> that serve? And such restriction would only apply if both parties adhere
> to it.
>
> Thanks,
> Paul
>
> T Satyanarayana-A12694 wrote:
>>
>>
>> -----Original Message-----
>> From: Dale Worley [mailto:[email protected]]
>> Sent: Tuesday, August 18, 2009 1:37 AM
>> To: T Satyanarayana-A12694
>> Cc: Paul Kyzivat; [email protected]
>> Subject: RE: [Sip-implementors] Can EP send media only peer supports
>>
>> On Sat, 2009-08-15 at 23:35 +0800, T Satyanarayana-A12694 wrote:
>>> Additional round trips should be made optional (only for
>>> implementations having concurrent codecs limitation).
>>>
>>> Additionally, why can't the spec be modified (or place in a BCP):
>>> 1. to allow only a sub-set (of what is present in the offer) in the
>>> answer (or even just one codec)
>>>> If you mean, "Is it allowed to put in the answer only a subset of
>>>> the
>> codecs that are in the offer", that is allowed now.
>>
>> No, I mean "Answerer must include only a sub-set of codecs present in
>> the offer". Or "Answerer must not include any codec not present in the
>
>> offer".
>>
>>> 2. to place a restrion on the offerer to only use one of the codecs
>>> listed in the intersection of answer & offer.
>> Some implementations use more than one codec, so that would have to be
>
>> considered a BCP.
>>
>> Dale
>>
>>
>>
>
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