Re: [MMUSIC] Existing missmatch between SDP mux and BUNDLE

[Christer Holmberg <[e-mail]>]

Hi,

>> SDP Mux says: 
>>
>>    The attributes and their associated values (if any) in the IDENTICAL
>>    category MUST be repeated across all the media descriptions under
>>    multiplexing.
>>
>> This I interpret as you really MUST include it each and every m= section that are bundled. 
> Agreed.

Perhaps the text should say "applies to all media descriptions", and then a sentence saying the individual usages need to define in which m- lines the attribute must be explicitly included..

>> While BUNDLE with its updated text says, that you only should include the SDP attribute in the m= sections
>> that are first on any a=group:BUNDLE line, and not in another unless they have unique 
>>transport information for the case of legacy fallback into individual lines. 
>
> It depends on how we interpret "associated with" - if it simply means "included as part of the media description" then I agree with you. 

That's what it means.

>> Thus, I see SDP-mux require inclusion of the SDP attribute on each m= section in all cases and BUNDLE to 
>> forbid such includion with the m= section in some cases. Thus, in those cases there is a conflict between 
>> two different MUST statements.
>
> I think you are right - maybe Christer can clarify the "associated with" term ? 

Unless the DRAFT clarifies that to you, we really need to do something...

Regards,

Christer







Den 2017-09-22 kl. 15:29, skrev Flemming Andreasen:
Hi Magnus

Can you elaborate on the mismatch ? I understand they do not say the same thing, but it's not clear to me they are actually in conflict with each other. 

How do you interpret the line ("associate" in particular)
<quote>
Otherwise the offerer/answerer MUST NOT associate such SDP attributes with the "m=" line. 
<quote>

Is the issue that bundle is relaxing the MUST requirement in bundle ? 

Thanks

-- Flemming 
On 9/20/17 7:20 AM, Magnus Westerlund wrote:
Hi,
We are currently in AUTH48 for draft-ietf-avtcore-rfc5285bis which references Bundle and SDP-Mux as it defines the mux category for its SDP attributes. As we made some last minute changes to MUX catergory for the extmap-allowed-mixed attribute we found some text needing changes. This anyway resulted in us noticing a missmatch between BUNDLE and sdp-mux.
So Bundle (-39) states: 
8.1. Mux Category Considerations 
   When an offerer or answerer associates SDP attributes with a bundled
   "m=" line (including any bundle-only "m=" line) associated with a
   shared address, IDENTICAL and TRANSPORT mux category SDP attributes
   [I-D.ietf-mmusic-sdp-mux-attributes] are associated with the "m="
   line only if the "m=" line is also associated with the offerer/
   answerer BUNDLE-tag.  Otherwise the offerer/answerer MUST NOT
   associate such SDP attributes with the "m=" line.  The rule above
   does not apply to a bundled "m=" line associated with a unique
   address.


However, SDP-mux states:

4.3.  Category: IDENTICAL

   The attributes and their associated values (if any) in the IDENTICAL
   category MUST be repeated across all the media descriptions under
   multiplexing.

To my understanding the first is correct, but the change in BUNDLE has not been 
reflected into SDP-mux doc. I assume that is in part due to its approved status. 
Has the authors tracked the set of changes that are needed due to changes in BUNDLE?

Do there exist a text change for this missmatch?


Cheers 

Magnus Westerlund 

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Media Technologies, Ericsson Research
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Torshamnsgatan 23           | Mobile [phone]
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-- 

Magnus Westerlund 

----------------------------------------------------------------------
Media Technologies, Ericsson Research
----------------------------------------------------------------------
Ericsson AB                 | Phone  [phone]
Torshamnsgatan 23           | Mobile [phone]
SE-164 80 Stockholm, Sweden | mailto: [e-mail]
----------------------------------------------------------------------