Re: [MMUSIC] Magnus Westerlund's Discuss on draft-ietf-mmusic-t140-usage-data-channel-12: (with DISCUSS)

[Christer Holmberg <[e-mail]>]

Hi Magnus,
    
>    I will clear my discuss as I think I strayed beyond the discuss criteria due
>    missing the sentence in the prior sub-section. 
>    
>    I think the text would clearer if one took slightly more consideration for under
>    what conditions in offers or answers the normative language will apply. For
>    exmaple. When an a=dcmap:3 with a subprotocol="t140" attribute is included ...
>    
>    This is of course statement dependent and I will not spend my time on suggesting
>    rewording of all of these. 
  
What about the following change:

OLD:

	"This section defines the SDP considerations that are specific to a T.140 data channel."

NEW:

	"This section, and its subsections, define the SDP considerations that are specific to a T.140 data channel,
	  identified by an SDP 'dcmap' attribute [I-D.ietf-mmusic-data-channel-sdpneg]  with a "t140" 
                attribute parameter value."
	
Regards,

Christer

    
    
    On Tue, 2020-04-07 at 15:05 +0000, Christer Holmberg wrote:
    > Hi,
    > 
    >  ----------------------------------------------------------------------
    >  DISCUSS:
    >  ----------------------------------------------------------------------
    >         
    >     >>>    Section 4.1:
    >     >>>    
    >     >>>       The offerer and answerer MUST NOT include the max-retr or the
    > max-
    >     >>>       time attribute parameters in the 'dcmap' attribute.
    >     >>>    
    >     >>>    This is just an example of a issue that is exists in basically all
    > of the
    >     >>>    RFC 2119 terminolgy using sentences in this section. The
    > formulation is that
    >     >>>    the offerer or answerer must do something with attributes or
    > parameters of
    >     >>>    the dcmap attribute. However, it is not stated to be specific to
    > the dcmap
    >     >>>    attribute that specifically specify something for a T.140 SCTP
    > stream. I
    >     >>>    think that scope restriction needs to be made more explicit for
    > these RFC 2119
    >     >>>    statements. Else they would have applicability as soon as one
    > support
    >     >>>    this specification.
    >     >>   
    >     >> The last sentence of Section 4 says:
    >     >> 
    >     >> "This section defines the SDP considerations that are specific to a
    > T.140 data
    >     >> channel."
    >     >
    >     > So why is that last and not first? 
    > 
    >     It is the last sentence of the parent section (4), and covers the
    > procedures in the section, including the subsections (4.x). This wording has
    > been used multiple times before.
    > 
    >     But, if you think it is more clear, I could say "The following sub
    > sections define the SDP considerations....".
    > 
    >     > So isn't this all scoped based on that there is an dcsmap line with a
    > subprotocol line stating t140 either included in an
    >     > offer that one is generating or responding to as an answerer? 
    > 
    >     Correct, and Section 4.1 describes the SDP details on how to indicate a
    > T.140 data channel, using the dcmap attribute.
    >     
    >     > As you see I am undertain if the sentence is sufficient to scope this
    > correctly.
    >     > Are there statement that are relevant outside of the scope of actually
    > offering
    >     > or answering a T140 offer? I think part of the uncertainty is if there
    > are
    >     > aspect that my be wrongly interpreted if one support T140 but it is not
    > actively
    >     > included? 
    > 
    >     The procedures in section 4 (including the sub sections) only apply to
    > T140.
    > 
    >    Regards,
    > 
    >    Christer
    > 
    > 
    > 
    > 
    >     Cheers
    >     
    >     Magnus Westerlund 
    >     
    >     
    >     ----------------------------------------------------------------------
    >     Networks, Ericsson Research
    >     ----------------------------------------------------------------------
    >     Ericsson AB                 | Phone  [phone]
    >     Torshamnsgatan 23           | Mobile [phone]
    >     SE-164 80 Stockholm, Sweden | mailto: [e-mail]
    >     ----------------------------------------------------------------------
    >     
    >     
    >     
    -- 
    Cheers
    
    Magnus Westerlund 
    
    
    ----------------------------------------------------------------------
    Networks, Ericsson Research
    ----------------------------------------------------------------------
    Ericsson AB                 | Phone  [phone]
    Torshamnsgatan 23           | Mobile [phone]
    SE-164 80 Stockholm, Sweden | mailto: [e-mail]
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