Re: [RAI] Conference Focus Indicating CCMP Support draft

[Paul Kyzivat <[e-mail]>]

On 4/11/13 1:50 AM, Shekh-Yusef, Rifaat (Rifaat) wrote:
> Adding the RAI distribution to this discussion per Robert's request.

IMO RAI isn't the best place for this discussion.
I fear that some people who care won't see this.
The right place to have the discussion of restructuring the ABNF for the 
info-param is sipcore. But I don't want to cross post, so lets reach 
some conclusion to this thread, and then if it becomes a sipcore concern 
we can post the conclusion there for confirmation.

I see three ways to handle this, two of which have already been mentioned:

1) revise the ABNF so in the future it can be extended without
    further redefinition:

    info-param = info-purpose-param / generic-param
    info-purpose-param = "purpose" EQUAL info-purpose-choices
    info-purpose-choices = "icon" / "info" / "card" / token
    info-purpose-choices =/ "ccmp"

2) revise the ANBF to just have the choices be just "token"
    and add an IANA registry for values.

3) just work around the existing ABNF in a cleaner way:

    info-param =/ "purpose" EQUAL "ccmp"

Which to do depends on how much work we want to go through now and how 
many new values we anticipate in the future. In this case, where the 
syntax isn't too complex and the number of new values is likely to be 
small I think (3) may be the simplest.

The choice between (1) and (2) depends on whether we want to spend 
cycles deciding what the criteria ought to be for adding new values in 
the future.

	Thanks,
	Paul

> Thanks Robert,
>
>> That _redefines_ Call-Info even if it leaves the syntax the same.
>> The definition for the header would be in _this_ document, not in 3261
>> if you leave the ABNF like this.
>
> I now understand your concern.
> I would like to go with the option of removing the ABNF and just define the new value.
>
>
> Do others see value with the second option:
>
>> But if you do mess with the ABNF, make this change:
>>
>> info-param = ( "purpose" EQUAL ( info-purpose-choices) ) / generic-param
>> info-purpose-choices = "icon" / "info" / "card" / "ccmp " / token
>>
>> so that  the _next_ draft that comes along that wants to add a purpose
>> choice can simply say
>> info-purpose-choices =/ "foo"
>>
>> If you go down this path, you should also check with the community
>> whether we should
>> create an IANA registry for these choices. I don't think it's worth it,
>> but there have been
>> similar conversations where the rough consensus was to create one.
>
>
> Thanks,
>   Rifaat
>
>
>> -----Original Message-----
>> From: Robert Sparks [mailto:[e-mail]]
>> Sent: Wednesday, April 10, 2013 1:29 PM
>> To: Shekh-Yusef, Rifaat (Rifaat)
>> Cc: Gonzalo Camarillo; [e-mail]; Mary Barnes; Alan Johnston
>> Subject: Re: Conference Focus Indicating CCMP Support draft
>>
>> On 4/10/13 12:08 PM, Shekh-Yusef, Rifaat (Rifaat) wrote:
>>> Hi Robert,
>>>
>>> Thanks for your feedback.
>>>
>>>> The one thing that sticks out is the complete redefinition of the
>>>> Call-Info header syntax just to add a parameter
>>>> to info-param.
>>> The draft is not changing the syntax of the Call-Info header; the
>> absoluteURI will be an XCON-URI and we are defining a new "ccmp" token
>> to indicate that the URI supports ccmp.
>>> Where do you see that we are redefining the syntax?
>> The draft contains this:
>>
>>      The following is the updated ABNF for the Call-Info header:
>>
>>         Call-Info   =  "Call-Info" HCOLON info *(COMMA info)
>>         info        =  LAQUOT absoluteURI RAQUOT *( SEMI info-param)
>>         info-param  =  ( "purpose" EQUAL ( "icon" / "info"
>>                        / "card" / "ccmp" / token ) ) / generic-param
>>
>> That _redefines_ Call-Info even if it leaves the syntax the same.
>> The definition for the header would be in _this_ document, not in 3261
>> if you leave the ABNF like this.
>>
>> At the very least, don't restate Call-Info and info. Redefine only
>> info-param.
>>
>> You could just define the value and not mess with the ABNF. That is the
>> avenue I would recommend.
>>
>> But if you do mess with the ABNF, make this change:
>>
>> info-param = ( "purpose" EQUAL ( info-purpose-choices) ) / generic-param
>> info-purpose-choices = "icon" / "info" / "card" / "ccmp " / token
>>
>> so that  the _next_ draft that comes along that wants to add a purpose
>> choice can simply say
>> info-purpose-choices =/ "foo"
>>
>> If you go down this path, you should also check with the community
>> whether we should
>> create an IANA registry for these choices. I don't think it's worth it,
>> but there have been
>> similar conversations where the rough consensus was to create one.
>>
>> Also, it's unfortunate that this conversation isn't on a list. If we
>> continue, please add a list to the distribution.
>> I suggest [e-mail].
>>
>> RjS
>>
>>
>>
>>>
>>> Regards,
>>>    Rifaat
>>>
>>>
>>>> -----Original Message-----
>>>> From: Robert Sparks [mailto:[e-mail]]
>>>> Sent: Wednesday, April 10, 2013 10:35 AM
>>>> To: Gonzalo Camarillo
>>>> Cc: Shekh-Yusef, Rifaat (Rifaat); [e-mail]; Mary Barnes; Alan
>> Johnston
>>>> Subject: Re: Conference Focus Indicating CCMP Support draft
>>>>
>>>> We had not yet started. The next step is for the authors to request
>>>> publication (when they believe it is ready),
>>>> and you or Richard can start fresh with an initial AD review.
>>>>
>>>> I skimmed the version of the draft linked to below - I still don't
>>>> expect controversy or much in the way of changes.
>>>> The one thing that sticks out is the complete redefinition of the
>>>> Call-Info header syntax just to add a parameter
>>>> to info-param. It would be much better to find a way to use the
>>>> Incremental Alternative (=/) production rule.
>>>> If that's not possible the way Call-Info is currently defined, we
>> should
>>>> redefine it _once_ to make it possible.
>>>> IIRC there are other things in flight that are touching Call-Info -
>> you
>>>> should make sure they're aligned.
>>>>
>>>> RjS
>>>>
>>>> On 4/10/13 3:01 AM, Gonzalo Camarillo wrote:
>>>>> Hi Robert,
>>>>>
>>>>> the authors of the draft below just sent us the email below. They
>>>>> mention you had agreed to AD sponsor it. What is the next step here
>> so
>>>>> that Richard or I can take this over?
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Gonzalo
>>>>>
>>>>> On 09/04/2013 9:47 PM, Shekh-Yusef, Rifaat (Rifaat) wrote:
>>>>>> Gonzalo, Richard,
>>>>>>
>>>>>>
>>>>>>
>>>>>> Mary and I have been working on the following "Conference Focus
>>>>>> Indicating CCMP Support" draft, which Robert agreed to AD sponsor a
>>>>>> while back.
>>>>>>
>>>>>> https://datatracker.ietf.org/doc/draft-yusef-dispatch-ccmp-
>>>> indication/?include_text=1
>>>>>>
>>>>>>
>>>>>> The draft is simple and straightforward which was discussed on the
>>>>>> DISPATCH mailing list.
>>>>>>
>>>>>> Robert Sparks, Alan Johnston, Cullen Jennings, and Adam Roach all
>>>>>> reviewed it and provided feedback which was incorporated into the
>>>> latest
>>>>>> version of the draft.
>>>>>>
>>>>>> Alan Johnston is the document shepherd and he worked on the writeup
>>>> for
>>>>>> this draft.
>>>>>>
>>>>>>
>>>>>>
>>>>>> Now that Robert is no longer an AD, can one of you please sponsor
>>>> this
>>>>>> draft instead?
>>>>>>
>>>>>>
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Rifaat
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>
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