Subject: Re: [MMUSIC] Comments on draft-ietf-mmusic-sdp-bundle-negotiation-16 - The rest from Magnus - Issue #12

From: Christer Holmberg <[email-masked]>
Date: Fri, 6 Mar 2015 12:15:10 +0000

Hi,

12. Section 8.5.1:
  
>>>>> In addition, the offerer MUST select an offerer BUNDLE-tag [Section 
>>>>> 8.2.2], even if the offerer does not suggest a new offerer BUNDLE 
>>>>> address.
>>>>>
>>>>> I don't understand what the above means. As long as one has a 
>>>>> bundle group the MIDs of the m= blocks needs to be included. If all 
>>>>> use the shared address, then it doesn't matter which is first. If 
>>>>> they are not, then the order matters. However, without terminating 
>>>>> the bundle group you can't avoid selecting a new offerer BUNDLE address.
>>>>
>>>> You are right that it doesn't matter, but SOME mid value has to be 
>>>> first in the attribute list.
>>>
>>> Yes, but can we write this in a way that is less confusing.
>>>
>>> OLD:
>>>
>>>   In addition, the offerer MUST select an offerer BUNDLE-tag
>>>   [Section 8.2.2], even if the offerer does not suggest a new offerer
>>>   BUNDLE address.
>>>
>>> NEW:
>>>
>>>   The BUNDLE-tag used MUST remain the same in the offer unless any of
>>>   the above exceptions occur, in which case the Offerer selects a new
>>>   BUNDLE-tag indicating the chosen BUNDLE address [Section 8.2.2].
>>>
>>> What could be further clarified is that for the cases where the 
>>> BUNDLE address is not changed, but the m= line that the BUNDLE-tag 
>>> pointed to no longer is part of the bundle, then one picks any of the other existing tags for m= lines that carries the bundle address.
>> 
>> I'll think of some text.
>> 
>
> Thanks

I was working on this, and I don't think the suggested text works.

Because, the "m=" line associated with the previously used offerer BUNDLE-tag may not even have been selected into the BUNDLE group.

In addition, I don't think the exceptions as such justify for modifying the BUNDLE-tag.

So, my suggestion is to simply say that the offerer BUNDLE-tag must be associated with the previously selected BUNDLE address.

	"In addition, the offerer MUST select an offerer BUNDLE-tag
	associated with the previously selected offerer BUNDLE address, unless
	the offerer suggests a new offerer BUNDLE address."

Regards,

Christer

---

From: Magnus Westerlund <[email-masked]>
Date: Fri, 6 Mar 2015 13:25:06 +0100

On 2015-03-06 13:15, Christer Holmberg wrote:
> Because, the "m=" line associated with the previously used offerer
> BUNDLE-tag may not even have been selected into the BUNDLE group.

Your are right, it would need to be the selected one from the answer
that should be maintained.
> modifying the BUNDLE-tag.

Yes, they are with the assumption that m= line being subject to any of
these exceptions are the one that was the one with the previous used
bundle-tag. But, I was not explicit about that, so you are right that
there are cases where these exceptions are performed on other media
descriptions.

> 
> So, my suggestion is to simply say that the offerer BUNDLE-tag must
> be associated with the previously selected BUNDLE address.
> 
> associated with the previously selected offerer BUNDLE address,
> unless the offerer suggests a new offerer BUNDLE address."

Sure, that is clear and works.

Cheers

Magnus Westerlund

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