[ogsa-wg] Re: [ogsa-naming-wg] ... without wsa:Address profile, AbstractName is meaningless ...

[Mark McKeown]

Hi Frank,
         The Web Architecture
(http://www.w3.org/TR/webarch/#identification)
discusses and provides guidance on the issues you describe
of IRI collision, IRI aliases etc. Does this document not
address the issues of the profile work you are suggesting?

When you advocate using the wsa:Address for the AbstractName
are you saying that there is no need for adding the AbstractName
element from WS-Naming into the EPR or are you saying that
the wsa:Address (or some combination of the
wsa:Address+wsa:ReferenceParameters) should be used in the
AbstractName element.

eg.
<wsa:EndpointReference
	xmlns:wsa="http://www.w3.org/2005/03/addressing"
	xmlns:name="http://ggf.org/name">
  <wsa:Address>http://ggf.org/example/B944388</wsa:Address>
  <name:AbstractName>http://ggf.org/example/B944388</name:AbstractName>
</wsa:EndpointReference>

cheers
Mark

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Mark Mc Keown                            RSS
Mark.McKeown at man.ac.uk 	                 Manchester Computing
+44 161 275 0601     		         University of Manchester
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

On Thu, 10 Nov 2005, Frank Siebenlist wrote:

> Without the proper uniqueness guarantees for the wsa:Address, the use of
> ws-naming's AbstractName is meaningless.
>
> The EPR with an embedded AbstractName essentially describes a binding
> between the Address and the AbstractName.
> One could argue that this binding is a bit of a flaky assertion without
> any way to specify time-validity or issuer.
> As a result, one can not see from an EPR alone when it was issued or
> whether it is still valid or not.
>
> An EPR-minter can decide to create a new EPR for a resource and reuse an
> Address that was used for an other resource before.
> This would yield the undesirable situation that you would have two EPRs
> with identical Addresses and two different AbstractNames associated with
> different resources, and the client would have no way to see which one
> of the EPRs is valid...
>
> For example, if I have two EPRs with the same Address, where one EPR
> includes an AbstractName that identifies MyBankAccount and the other
> includes an AbstractName identifying YourBankAccount, then one of us
> will not be happy with that situation...
>
> In order to avoid this ambiguity, we need the guarantee from the
> EPR-minter that Address values will not be reused for different
> resources: for all times, the Address should either refer to that one
> and only resource, or it should be invalid (and it is allowed to change
> between those two states).
> Furthermore, the EPR-minters should ensure that globally unique
> Addresses are used for a resource such that different EPR-minters do not
> (accidentally) use the same Address for different resources.
> The described uniqueness properties of the Address constitutes a
> required EPR-minter profile for the use of AbstractNames.
>
> ---
>
> This has been reiterated in a number of emails, but i wanted to call it
> out separately to facilitate the discussion whether the observation
> holds water and if so, whether such a EPR-minter Address-profile should
> become part of the ws-naming spec.
>
> Again, I would especially welcome comments/reactions/acknowledgments
> from the ws-naming authors...
>
> Regards, Frank.
>
> PS. Note that everywhere I wrote "Address" above, it should probably be
> substituted by "Address+ReferenceParameters", but this simplification
> doesn't change the observation.
>
> --
> Frank Siebenlist               franks at mcs.anl.gov
> The Globus Alliance - Argonne National Laboratory
>
>