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RE: Intermediaries - various cases

From: Ugo Corda <UCorda@SeeBeyond.com>
Date: Thu, 26 Sep 2002 19:14:23 -0700
Message-ID: <C513FB68F8200244B570543EF3FC65370A855B37@MAIL1.stc.com>
To: "'Ricky Ho'" <riho@cisco.com>, "'www-ws-arch@w3.org'" <www-ws-arch@w3.org>
>The initial sender MUST specify the destination and optionally a list of
intermediaries (as well as which intermediaries it delegates authority to
modify his route).

This requirement could be part of a routing extension spec, but I don't
think it's part of the basic SOAP 1.2 spec. In fact, even though I might
think of the pub sub node more naturally as the ultimate receiver, I cannot
remember anything in SOAP 1.2 that would prevent me from considering the pub
sub node as the intermediary instead. (If somebody believes that SOAP 1.2
rules out this interpretation, please point it out to me).
 
Ugo

-----Original Message-----
From: Ricky Ho [mailto:riho@cisco.com]
Sent: Thursday, September 26, 2002 5:44 PM
To: Ugo Corda; 'www-ws-arch@w3.org'
Subject: Re: Intermediaries - various cases


I think this is the second case.  The client is sending a request to a
"Publishing Service", which has an implementation that forward the request
to a bunch of subscribers.

I consider "intermediaries" are message pre/post-processing nodes along the
path of from the initial sender and the ultimate receiver.  And
"intermediaries" can only modify the route in a restricted way.  The initial
sender MUST specify the destination and optionally a list of intermediaries
(as well as which intermediaries it delegates authority to modify his
route).

Rgds, Ricky

At 02:37 PM 9/26/2002 -0700, Ugo Corda wrote:



The discussion about intermediaries near the end of today's conf call
reminded me of a couple of cases I have been thinking about in the context
of queuing infrastructures.

Suppose I have a store-and-forward node to which I send SOAP messages to be
forwarded to particular destinations. I specify the destination in an
extension header, and I send the SOAP message to the store-and-forward node.
The store-and-forward node receives my SOAP message and sends it to the
final destination (possibly later, if the final destination is not available
right away). It looks like in this case the Service Requester (according to
our architecture diagram) is the node issuing the initial SOAP message, and
the Service Provider is the final destination node. So the store-and-forward
node must be the Intermediary.

But now let's think about a case where I have a publish-and-subscribe node.
I send a SOAP message to that node with the intent that my message be
distributed to any subscriber (I don't even know the address of those
subscribers). So I send my SOAP message to the publish-and-subscribe node
(the only node I am aware of) without specifying any final destination. In
this case, is the publish-and-subscribe node still an intermediary, and are
the destination nodes Service Providers? Or is the publish-and-subscribe
node the Service Provider, which engages in separate interactions with the
subscriber nodes? Or is there no single answer to these questions, and it
all depends on the logical view that I want to apply to the scenario?

Ugo 
Received on Thursday, 26 September 2002 22:15:00 GMT

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