Re: [rtcweb] Does RID require the same ext id for all the m= sections?

But according to RFC 5285:

    An extension URI with the same attributes MUST NOT appear more than
    once applying to the same stream, i.e., at session level or in the
    declarations for a single stream at media level.

And

    In addition, as noted above,
    the IDs used MUST be unique for each stream type for a given media,
    or for the session for session-level declarations.

So it is not possible to have same URN with exact parameters with 
different IDs for same "stream" (whatever "stream" is meant to be 
nowadays), and I would (at least) assume that each URN cannot appear 
more than once in each m-line with same parameters.

Also, IMHO, bundle should be updated to make this requirement session 
level, as it is done with the ID uniqueness.

Best regards
Sergio
On 11/09/2017 15:34, Mo Zanaty (mzanaty) wrote:
> See bundle section 13.
>
> https://tools.ietf.org/html/draft-ietf-mmusic-sdp-bundle-negotiation-38#section-13
>
> The same ID must always map to the same URN. Different IDs can map to 
> the same URN as aliases. (The latter is not stated but implied.)
>
> Mo
>
> On Sep 11, 2017, at 8:49 AM, Iñaki Baz Castillo <ibc@aliax.net 
> <mailto:ibc@aliax.net>> wrote:
>
> On Sun, Sep 10, 2017 at 8:22 PM, Mo Zanaty (mzanaty) 
> <mzanaty@cisco.com <mailto:mzanaty@cisco.com>> wrote:
>> All extmap IDs must be consistent in all bundled m= sections, just 
>> like PTs.
>
> Thanks.
>
> However, what does "consistent" mean? I assume/expect that the extmap
> ID (for example a=extmap:4) cannot exist in two different m= sections
> pointing to different extension URLs, right?
>
> But, and given that you told about PTs, it's perfectly valid that two
> different PTs point to the same codec+condiguration within the same m=
> section or in different m= sections.
>
> So, could a m=audio section have an "a=extmap:4 urn:foo" line while a
> m=video section has "a=extmap:8 urn:foo"? or should both use extmap ID
> 4?
>
> For example, the extmap ID for MID must be *UNIQUE* across all the
> m=sections. Does the same constrain exist for the extmap ID for RID?
>
>
>
> -- 
> Iñaki Baz Castillo
> <ibc@aliax.net <mailto:ibc@aliax.net>>
>
>
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