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Subject: RE: [xri] Compromise Conceptualization Towards CD-02
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Gabe, I think I understand what you're driving
for in this message – to harmonize our conceptual models about XRI resolution
and "what XRIDs describe" so we can get CD-02 moving out the door. But after reading it all I'm afraid it
didn't make anything clearer for me. Specifically, we already have the
following definition of "authority" in the XRI Syntax 2.0 Committee
Draft 02 glossary: *****BEGIN EXCERPT***** Authority
(or Identifier Authority) In
the context of identifiers, an authority is a resource that assigns identifiers
to other resources. Note that in URI syntax as defined in [URI], the “authority” production
refers explicitly to the top-level authority identified by the segment
beginning with “//”. Since XRI syntax supports unlimited
federation, the term “authority” can technically refer to an
identifier authority at any level. However, in the “xri-authority”
and “iauthority” productions (section 2.2.1), it explicitly refers to the top-level identifier authority. See also “IRI Authority”
and “XRI Authority” ******END***** Are you suggesting that this definition
needs to be changed in any way? For what it's worth, I've had the
following conceptual model about XRIs, resources, authorities, and XRIDs: * An XRI (Extensible Resource Identifier) identifies
a resource. * An XRI may be resolvable into an XRID (an
XML document) that describes the resource identified by the XRI. * The network endpoint responsible for
assigning an XRI to a resource and returning an XRID describing that resource is
the authority for both the XRI and the corresponding XRID. * One function of XRIDs is to tell XRI resolvers
how to further resolve an XRI. By the above definition, this applies both to
the resolution of authority subsegments within the authority part of an XRI,
and resolution of the local part of the XRI. In other words, XRI resolution is
the complete set of steps that may be necessary to resolve an absolute abstract
XRI into an absolute concrete URI which can then be resolved via DNS, IP, or
other means. Again, to the extent that it is helpful,
can you describe how your proposed conceptual model differs from this one? Thanks, =Drummond From: Wachob, Gabe
[mailto:gwachob@visa.com] A number of us attended the Internet Identity Workshop (http://www.socialtext.net/iiw2005)
and lots of folks were interested in XRI and working with us to use XRI with
their identity solutions/approaches/grassroots efforts. If we're going to catch
this wave of interest, we've really got to close on these specs soon. However, in our recent phone calls, we haven't had much
progress in reaching consensus on the different proposals for CD-02. I think
this is largely because there's been some divergence in the various parties'
conceptual models, resulting in a difference in some base assumptions about
concepts like authority, whats being identified by the authority section of an
XRI, and the concept of "authoritativeness". We're actually not far apart in terms of what gets defined
on the wire, but we need to close on the conceptual model - once we do that, I
think concensus on defining CD-02 will be quick. I propose in this email some slight tweaks for the
conceptual models that have been put forth by Dave McAlpin and WHAT IS AN AUTHORITY? We (Mike/me) believe that to trust an authority, you are
saying that you have a relationship with that authority. In our case, that may
mean a contract or other financial arrangement. You can't have that with a
document. Therefore, we believe the definition of authority is at least a
entity with which you can have some sort of contract - ie an organization.
HOWEVER, this is a philosophical discussion I don't think we should get into -
I believe that for the purposes of resolution, we should stop talking about
"authority" because its more confusing than useful. PROPOSAL: Restrict our use of the word "authority"
to the thing meant in RFC 3896 - the syntactic construct after // and before
the first /.. PROPOSAL: Define the XRID as the complete expression
(where complete means "as much as one wish's to
advertise) of one resource's knowledge about the identified
resource. Thus, when you resolve and authority segment, the last XRID you get
describes the resource identified by the XRI authority segment, and we say
nothing more. Note I've specifically not used the term "XRI
Authority". This ends up being a recursive definition - the resource
providing the XRID describing the resource identified by n authority
subsegments is the one identified by n-1 authority subsegments. (I'm not sure
how elements like "Resolved/Query" or "Expires" fit
into this though). PROPOSAL: Replace the term "XRI Authority
Resolution" with the term "XRI Authority Segment Resolution",
emphasizing the fact that XRI Authority resolution is not the resolution of an
XRI Authority (since the concept of an "XRI Authority" is now more
confusing than useful). What we really have is a resource that provides XRI
Authority Subsegment Resolution service. WHAT DOES IT MEAN FOR A RESOURCE TO BE
"AUTHORITATIVE" It important for us to be able to say that a particular
resource (what we used to call an XRI Authority and what I'll now call
"Resource A") is authoritative for identifiers built from the
identifier we used to get to Resource A. That is, if Resource A is identified
as xri://@foo*bar, then I'd like to be able to talk about the fact thta
xri://@foo*bar is "authoritative" for xri://@foo*bar*baz and
xri://@foo*bar/baz, etc But if we accept the assertion that the XRID is the
final expression of authority for a resource, then what does it mean to have an
X2R service described in the XRID? For example, is the X2R service
authoritative or the XRID? (in other words, is the provider of the X2R
service "authoritative" for the path part of the XRI or is the
XRID-described resource authoritative for the path part)? PROPOSAL: The conceptual answer is that the resource
described by the XRID is authoritative (and the XRID is the expression of this
authority) BUT ALSO that the authority can delegate authority to other services
(even to other resources identified by synonym XRIs). I'm still concerned that we have a lot of conceptual
groundwork to do to describe XRI Resolution. I'm hoping that at least we can
agree on a conceptual model among ourselves thats relatively simple for *us*,
however. -Gabe
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