[Nmc-wg] NMC Ma document review

[Jason Zurawski]

Hi Piotr & All;

> I have reviewed the document and have one question. Section 4 is
> DataInfo message type. As wiki says it is probably used only in pSPS. In
> geant perfsonar MA services (SQL MA nad RRD MA) don't use it and
> actually I don't know anything about this type of message. Could you
> tell me what is used for? And should we implement it in our services to
> be compatible with pSPS or it is not obligatory message type?

The message was implemented as a specific use case for a pSPS service, 
it was discussed in a previous DICE meeting but at the time it was not 
recommended for implementation everywhere.  This message is similar to a 
MetadataKeyRequest, but returns additional information inside of the 
'key' element.  See here (under 'Future Directions'):

https://wiki.man.poznan.pl/perfsonar-mdm/index.php/PerfSONAR_developer_meeting_-_in_Ann_Arbor_08#Tuesday.2C_9_September

I would not recommend implementing it since it breaks the primary rule 
for the 'key' element of forcing a client to look inside and find 
content (keys should be opaque).

The solution is not very clean, and I would prefer that we didn't even 
bother to document this message because of this reason.  We could 'fix' 
the key issue but, this also means more time developing a protocol 
(something I would prefer we didn't do at this time since we need to 
make progress in documentation).

Comments?

-jason