Giovanni,
I apologize for the long delay in replying
– I was at the OASIS Symposium the week before last and am still catching
up on lists.
See [=Drummond] inline.
From: Giovanni
Bartolomeo [mailto:giovanni.bartolomeo@uniroma2.it]
Sent: Friday, April 13, 2007 9:26
AM
To: xri@lists.oasis-open.org;
xdi@lists.oasis-open.org
Cc: steven.churchill@ootao.com;
andy.dale@ootao.com
Subject: [xdi] notifications for
XDI? (was Re: prototype and consequent feedback on XDI primitive)
Dear All,
reading Andy's reply I realized to haven't been so clear with my use case; I'm
sorry for this, I'll try again to better explain this idea.
The issue we're facing is that there should be some cases in which the terminal
or the device running the CLIENT side of the XDI framework might be needed of
be notified whenever certain data change. This is quite common in
telecommunications environments.
[=Drummond] Yes, I agree with this use
case.
For example, OMA XDM (
http://www.openmobilealliance.org/release_program/docs/XDM/V1_0-20060612-A/OMA-TS-XDM_Core-V1_0-20060612-A.pdf
)
"defines the common protocol for access and manipulation of XML
documents by authorized principals. This specification reuses the IETF XML
Configuration Access Protocol (XCAP).
XCAP defines:
• A convention for describing
elements and attributes of an XML document as a HTTP resource, i.e., accessible
via an
HTTP URI
• A technique for using HTTP GET, PUT
and DELETE methods for various document manipulation operations (e.g.,
retrieving/adding/deleting elements/attributes, etc.)
• The concept and structure of an
XCAP Application Usage by which service or enabler specific documents can be
described
• A default authorization policy for
accessing and manipulating documents"
sounds
familiar? Basically XDM/XCAP is roughly similar to XDI/XRI, but with many
limitations
- it can handle just XML documents
- it doesn't define an abstract protocol and binding mechanisms
- it doesn't keep the concept of data link between documents
- ...
Though so "primitive" compared to XDI/XRI, it's the OMA standard to
be used in telco!!!
but the interesting thing is that:
"This specification also defines a
technique by which changes to such XML documents can be conveyed to an XCAP
CLIENT. This reuses an IETF-defined SIP event package by which an XDM Client
subscribes to changes to all documents that it owns."
this feature (subscription/notification) is instead
missing in XDI! Why we don't think at an extension of the current spec to
support it?
Two issues to be discussed are:
- usefulness (what you think?)
[=Drummond] I have long felt that XDI
notifications are very useful; it has always my assumption we would specify
them.
- feasibility and concrete bindings (do we need to use SIP as a concrete
binding for this purpose? Maybe we can rely on the RSS protocol? Etc.)
[=Drummond] This is what needs the most
discussion. Both SIP and RSS have something to offer.
(It is even trivial to say that in case of positive reactions we'll be more
than happy to take the task of writing a (more or less formal) document to
propose such an extension!)
[=Drummond] That would be most welcome. As
the minutes of the XRI/XDI TC meeting in San Diego indicated, we are about to
formally update the XDI TC charter. I’ll be sending more email about that
this week. Once we’ve done that and have the rest of the XRI 2.x Working
Drafts ready, I’d really like to move forward rapidly with drafting the XDI
1.0 specs.
[=Drummond] Are you thinking that this
would need to be a separate specification, or included under the XDI Protocols
and Bindings specification as listed on http://wiki.oasis-open.org/xdi/CharterRevision02
?
Your comments will be welcome!!! (unfortunately I'll be out of office next
week, so time of reaction will be not elevated; however, I've just given the
kick-off :-)
[=Drummond] And I will be out of the
office most of this coming week at the Higgins f2f in Austin, but I’ll be
online there, and will be sending out XRI/XDI TC messages in preparation for
our regular telecon this coming Thursday.
Best,
=Drummond