Re: accept-types [was Re: Fwd: Re: Adrian Farrel's Discuss on draft-ietf-simple-chat-16: (with DISCUSS and COMMENT)]

On Sep 5, 2012, at 9:35 AM, Miguel A. Garcia <[email protected]> wrote:

> I am now addressing the issue with accept-types and accept-wrapped-types.
> 
> There are two affected sections:
> 
> Section 5.2 discusses the SDP offer/answer when joining a chat room. The text now reads:
> 
>          The conference focus of a chat room MUST include support for
>          a <xref target="RFC3862">Message/CPIM</xref> top-level
>          wrapper for the MSRP messages by setting the 'accept-types'
>          MSRP media line attribute in the <xref target="RFC3264">SDP
>          offer or answer </xref> to include 'Message/CPIM'.

_only_ Message/CPIM, right? Or can other media types be included at the root?

> The
>          actual payload type is negotiated in the
>          'accept-wrapped-types' attribute in SDP (see <xref
>          target="RFC4575">RFC 4575 </xref> for details). There is no
>          default wrapped type. Typical wrapped type values can
>          include: text/plain, text/html, image/jpeg, image/png,
>          audio/mp3, etc.

Assuming you mean 4975, it looks good. We could mention the use of "*", but I think that's already covered by the reference, and we don't want to restate too much here.

> 
> 
> The other paragraph is in Section 6.1 (Regular messages), when we want to say that the MSRP SEND request needs to use one of the payloads negotiated in the accept-wrapped-types:
> 
> 	  The SEND request MUST contain a top-level wrapper of type
> 	  'Message/CPIM' according to <xref target="RFC3862">RFC
> 	  3862</xref>. The actual instant message payload MUST be
> 	  included as payload of the 'Message/CPIM' wrapper, and,
> 	  according to <xref target="RFC4575"> RFC 4575</xref>, it
> 	  needs to be one of those negotiated in the
> 	  'accept-wrapped-types' attribute in SDP.
> 
> Please note that in this last paragraph there is a bug in the current version of the draft. The last sentence incorrectly pointed to the 'accept-types' attribute, rather than the 'accept-wrapped-types'. I believe the proposed text above is now correct.

Looks good, again assuming you mean 4975.

> 
> /Miguel
> 
> 
> On 05/09/2012 9:19, Miguel A. Garcia wrote:
>>>>> >>>>---
>>>>> >>>>
>>>>> >>>>Section 6.1 (trivial nit)
>>>>> >>>>
>>>>> >>>>The SEND request MUST contain a top-level wrapper of type
>>>>> >>>>'Message/ CPIM' according to RFC 3862 [RFC3862].  The actual
>>>>> >>>>instant message payload MUST be included as payload of the
>>>>> >>>>'Message/CPIM' wrapper and MAY be of any type negotiated in the
>>>>> >>>>SDP 'accept-types' attribute according to the MSRP rules.
>>>>> >>>>
>>>>> >>>>I think s/MAY/may/. That is, a type must be set, and the type must
>>>>> >>>>be only one of those that has been negotiated.
>>>>> >>>>
>>>>> >>>>
>>>> >>>
>>>> >>>I think this MAY should actually be a MUST, because as you said, a
>>>> >>>types must be said, and this type cannot be anyone, but it MUST be
>>>> >>>one of those negotiated.
>>> >>
>>> >>This is already mandated in RFC4975 (as you go on to say...). The only
>>> >>thing new is the normative requirement for a particular wrapper type.
>>> >>It might be worth commenting that this is accomplished by putting only
>>> >>Message/CPIM in accept-types, and all allowed leaf types in
>>> >>accept-wrapped-types.
>>> 
>>> Ok, we can clarify it. Actually, we do not mention what can go in an
>>> accept-wrapped-types, because it was obvious that any type can go in. But
>>> it might be worth adding some explicit mention to it.
>>> 
> 
> -- 
> Miguel A. Garcia
> +34-91-339-3608
> Ericsson Spain
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