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

[Flemming Andreasen <[e-mail]>]

On 9/22/17 10:56 AM, Magnus Westerlund wrote:
> 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.
> 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.


> 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 ?

Thanks

-- Flemming


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