Re: [MMUSIC] AD Evaluation of draft-ietf-mmusic-rfc4566bis-32

Paul Kyzivat <pkyzivat@alum.mit.edu> Thu, 14 March 2019 16:56 UTC

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From: Paul Kyzivat <pkyzivat@alum.mit.edu>
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Date: Thu, 14 Mar 2019 12:56:19 -0400
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Subject: Re: [MMUSIC] AD Evaluation of draft-ietf-mmusic-rfc4566bis-32
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On 3/14/19 12:26 PM, Colin Perkins wrote:
>> On 14 Mar 2019, at 16:23, Paul Kyzivat <pkyzivat@alum.mit.edu 
>> <mailto:pkyzivat@alum.mit.edu>> wrote:
>> On 3/14/19 11:02 AM, Colin Perkins wrote:
>>>> On 12 Mar 2019, at 15:41, Paul Kyzivat <pkyzivat@alum.mit.edu 
>>>> <mailto:pkyzivat@alum.mit.edu>> wrote:
>>>> On 3/12/19 7:08 AM, Colin Perkins wrote:
>>>>>>>>>> This is a normative requirement of RTP, however. If we want to 
>>>>>>>>>> avoid normative examples, which I’d agree makes sense, then 
>>>>>>>>>> this needs to be rewritten as just “An RTP-based system in 
>>>>>>>>>> recvonly mode SHOULD…”..
>>>>>>>>>
>>>>>>>>> That is the way it was. The change from "SHOULD" to "should" 
>>>>>>>>> was to make it non-normative.
>>>>>>>>>
>>>>>>>>> Or were you requesting to remove “e.g."?
>>>>>>>> Remove the “e.g.”, yes, but also change “should” back to “SHOULD”.
>>>>>>>
>>>>>>> I thought the point was that the RTP specs are normative and this 
>>>>>>> is only an example, and so shouldn't be normative.
>>>>>>
>>>>>> I do not have the text in front of me, but I agree that examples 
>>>>>> should not be stated normatively.
>>>>> This is documenting a perhaps unexpected interaction between SDP 
>>>>> and RTP. That is, when set to recvonly in SDP, an RTP endpoint 
>>>>> SHOULD send RTCP. I do think that it’s important that we spell this 
>>>>> out clearly here, with normative language.
>>>>
>>>> I'm neutral here whether its normative or not. If it is to be a 
>>>> normative SHOULD, can we please include some "unless" text 
>>>> indicating the conditions when it may be omitted? Better yet, turn 
>>>> it into an "if NOT x then MUST ..." form.
>>> I don’t think I can summarise the rules around when RTCP is, or is 
>>> not, to be sent as a simple condition. If more detail is needed, I 
>>> suggest “An RTP-based system in recvonly mode SHOULD still send RTCP 
>>> packets as described in [RFC3550] Section 6”.
>>
>> I'll put this in if it is the consensus. But this appears to give 
>> license to someone to ignore RFC3550. (I have talked to people who 
>> have said "SHOULD isnt a firm requirement so I don't need to do it.)
>>
>> If that SHOULD is changed to MUST, then it will still mean that RTCP 
>> can be avoided in whatever cases RFC3550 allows. Specifically:
>>
>> "An RTP-based system in recvonly mode MUST still send RTCP packets as 
>> described in [RFC3550] Section 6.”
> 
> I’m happy for you to change this to a MUST in that manner.

OK. I'll do it that way.

	Thanks,
	Paul