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

[Frank Siebenlist]

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