Re: [MMUSIC] BUNDLE Weekly Summary: Assumptions

Martin Thomson <martin.thomson@gmail.com> Fri, 10 May 2013 22:24 UTC

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Date: Fri, 10 May 2013 15:23:52 -0700
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From: Martin Thomson <martin.thomson@gmail.com>
To: Eric Rescorla <ekr@rtfm.com>
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Cc: "Cullen Jennings \(fluffy\)" <fluffy@cisco.com>, "mmusic@ietf.org" <mmusic@ietf.org>, Christer Holmberg <christer.holmberg@ericsson.com>
Subject: Re: [MMUSIC] BUNDLE Weekly Summary: Assumptions
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On 10 May 2013 15:17, Eric Rescorla <ekr@rtfm.com> wrote:
> On Fri, May 10, 2013 at 3:16 PM, Martin Thomson <martin.thomson@gmail.com>
> wrote:
>>
>> On 10 May 2013 15:05, Eric Rescorla <ekr@rtfm.com> wrote:
>> > I'm sorry to be slow today, but can you point me to the specific MUST
>> > NOT in
>> > RFC 5888.
>>
>> I struggled to find it too.  It's in 9.2:
>>
>>    SIP entities refuse media streams by setting the port to zero in the
>>    corresponding "m" line. "a=group" lines MUST NOT contain
>>    identification-tags that correspond to "m" lines with the port set to
>>    zero.
>
> This feels like something we could relax for the offer.

Absolutely.  It seems a little arbitrary.  That said, I'd like to
understand why the MUST NOT exists.  Of the groupings I understand, I
can't think of a reason not to allow negotiated-off lines, but I'm
prepared to be surprised.