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

[Christer Holmberg <[e-mail]>]

Hi,

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 DISCUSS:
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    >>>    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 
    
    
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