Re: [siprec] Ben Campbell's No Objection on draft-ietf-siprec-metadata-20: (with COMMENT)

["Ben Campbell" <[e-mail]>]

On 9 Mar 2016, at 16:51, Paul Kyzivat wrote:

> On 3/9/16 5:40 PM, Ben Campbell wrote:
>
>
>> I read that to mean that the SRS builds a database over time, and
>> recognizes that the same CS arrived in two different xml documents, 
>> and
>> therefore associates it with the <recording> element of each?
>>
>> If so, that seems to conflict with the statement in the 2nd to last
>> paragraph in section 4, that says the model represents a snapshot. I
>> think maybe an XML document represents a snapshot, but the model
>> represents metadata accumulated over time. This would explain some
>> confusion I had over things like CSRS Association.
>
>
> The SRC delivers a series of xml snapshots over the RS. We don't 
> mandate what the SRS does with those. But we try to provide sufficient 
> information so that it *could* build up a database such as you 
> describe.

Keeping a history may not be required, but there seems to be 
relationships in the model that cannot ever occur in real life unless 
the SRS builds a cross-snapshot picture. (E.g.,  a given CS associated 
with more than one RS, and much anything useful with CSRS associations).

>
>
>> In any case, I don't get a sense of how this works from the draft. I
>> think it would benefit from a section that describes the high-level
>> operation (unless that's already in another document, in which case a
>> reference would help.)
>
>
> I *thought this was evident. Maybe not.

Maybe I missed something, but the only thing I find on the subject is 
the penultimate paragraph in section 4, which says:

" The model allows the capture of a snapshot of a recording's metadata
    at a given instant in time.  Metadata changes to reflect changes in
    what is being recorded.  For example, if a participant joins a
    conference, then the SRC sends the SRS a snapshot of metadata having
    that participant information (with attributes like name/AoR pair and
    associate-time.) "

To me that suggests that the model only describes an instant in time. 
One might infer otherwise from the document as a whole, but I think a 
more explicit explanation of assumptions would be helpful for someone 
coming newly to this work.

Ben.