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RE: Who Faulted (was RE: Proposed rewrite of Part 1, section 2 (l ong) )

From: Henrik Frystyk Nielsen <henrikn@microsoft.com>
Date: Thu, 31 Jan 2002 21:32:49 -0800
Message-ID: <79107D208BA38C45A4E45F62673A434D06569D5D@red-msg-07.redmond.corp.microsoft.com>
To: <noah_mendelsohn@us.ibm.com>, <skw@hplb.hpl.hp.com>
Cc: "Jacek Kopecky" <jacek@systinet.com>, <xml-dist-app@w3.org>, <xml-dist-app-request@w3.org>

>Regarding node names vs. role names : first of all, I think we've been 
>clear that role names can be chosen to identify a specific node, or to 
>identify some more abstract purpose (next, cachemanagers, 
>etc.)

I agree with the overall trend but I think it is safe to say that
regardless of the level of abstractness, a role name identifies a node
in the very sense that it for a particular purpose is the resource
identified by that name. This doesn't mean that it has to be the only
node for which this is true, this all depends on the mechanism by which
identity is discovered. In other words, it depends on the resolution
mechanism, and here I mean resolution in the broadest possible sense. In
some instances, the resolution process is tied to DNS, in others it is
not. In general, we have nothing to say about it other than we allow all
of the above. The "next" URI is a splendid example of a resolution
process that is entirely independent of DNS.

>Jean Jacques is right that 4.4.3 needs some cleanup, but I 
>don't think the 
>notion of role name is broken, and I don't think we should be in the 
>business of prescribing how many URI's might be used to 
>identify a node (I 
>believe the web architecture is clear that the same resource 
>can easily 
>have multiple URIs, none of which is necessarily preferred 
>over others.) 
>So, I think none of this is broken in the current spec, except for the 
>need to clean up 4.4.3.

I don't disagree with the effect of this statement although I would
formulate it as being the result of a slightly different model. Rather
than saying that a resource can have multiple URIs, I think it is a
simpler model if we say that each URI identifies a resource and under
certain conditions, two or more resources can be said to be "equal". The
"equality" can be expressed in a variety of ways and may be tied to the
notion of the resolution process above.

If we again look at the "next" URI, then it is considered equal to
whatever other URI identifies a SOAP node in the context of SOAP
processing. If, however, we look at the "next" URI and some other URI
identifying a SOAP node in some other context then they may not be
equal. An HTTP client would for example never consider them to be equal
because it doesn't operate within the SOAP processing context.

>During that processing, an error occurs that 
>results from some interaction between the transaction header and the 
>processing for the header that is labeled "next".  I think its very 
>reasonable to ask the node to identify itself with a URI, and I don't 
>think we should say anything about what that URI is.  If the 
>node chooses 
>a URI that matches a role, so be it.  If it chooses a role 
>that matches 
>one used by the transport bindings, fine too, or it can use 
>anything else. 
> Specifications for applications of or deployments of SOAP might well 
>mandate conventions for the nature of such URI's, but I don't think we 
>should.

I agree with this.

As I mentioned in my previous mail, I think section 2 is fine as is.

Henrik
Received on Friday, 1 February 2002 00:33:28 GMT

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