W3C home > Mailing lists > Public > www-ws-arch@w3.org > December 2003

RE: Intermediaries

From: Ugo Corda <UCorda@SeeBeyond.com>
Date: Fri, 5 Dec 2003 12:16:54 -0800
Message-ID: <EDDE2977F3D216428E903370E3EBDDC9032B89CC@MAIL01.stc.com>
To: "Cutler, Roger (RogerCutler)" <RogerCutler@chevrontexaco.com>, "Ricky Ho" <riho@cisco.com>, <www-ws-arch@w3.org>

Roger,

I would not go for the deep philosophical meaning in all this. We just have to acknowledge that specs have always some underspecified areas. Maybe when WS-I decides to tackle intermediaries in a Basic Profile (right now they are just "extension points"), it will pick a particular interpretation of this subject and run with it.

In my view, computer technologies are not the right place to look when you want to satisfy your philosophical interests ;-).

Ugo

> -----Original Message-----
> From: www-ws-arch-request@w3.org [mailto:www-ws-arch-request@w3.org]On
> Behalf Of Cutler, Roger (RogerCutler)
> Sent: Friday, December 05, 2003 11:59 AM
> To: Ricky Ho; www-ws-arch@w3.org
> Subject: RE: Intermediaries
> 
> 
> 
> I might also comment that Frank seems to have a more Olympian view of
> the matter and, as far as I can tell, is saying that the messages are
> "the same" because we DEFINE them to be the same, not because they are
> judgeed to be the same by any criteria.  Maybe I didn't put this quite
> right because I don't understand what he is saying, so I 
> didn't make an
> effort to capture it.
> 
> -----Original Message-----
> From: www-ws-arch-request@w3.org 
> [mailto:www-ws-arch-request@w3.org] On
> Behalf Of Cutler, Roger (RogerCutler)
> Sent: Friday, December 05, 2003 1:53 PM
> To: Ricky Ho; www-ws-arch@w3.org
> Subject: RE: Intermediaries
> 
> 
> 
> Again, this is sort of third hand -- I have been trying to 
> capture what
> other people said.  However, I believe that the sense I got from David
> Booth and others is that the issue of whether the message going from A
> to I is "the same" as that going from I to B is something 
> that has to be
> considered in the context of "the application", broadly 
> understood. That
> is, "the application" includes both what A is doing and what 
> B is doing.
> So I guess that there is a God-like observer involved in this scenario
> or something.  I don't see how you can think about 
> choreography without
> postulating some observer that can see everything that 
> happens and whose
> observations correspond absolute reality, as opposed to what 
> is visible
> to any particular participant.
> 
> -----Original Message-----
> From: Ricky Ho [mailto:riho@cisco.com] 
> Sent: Friday, December 05, 2003 1:30 PM
> To: Cutler, Roger (RogerCutler); www-ws-arch@w3.org
> Subject: RE: Intermediaries
> 
> 
> 1) I can't see how B or C can determine whether the modified 
> message is
> the 
> same message given that they haven't seen the original one.
> 
> 2) SOAP doesn't have the "SAME MESSAGE" concept and therefore 
> it is NOT 
> possible to make such differentiation at the SOAP level.  In 
> some other 
> spec (such as RM), the "SAME MESSAGE" concept is very important, there
> they 
> define the messageID explicitly.
> 
> About your encryption scenario, if determining the "SAME MESSAGE" is 
> important to me, then I have to decrypt the messageID.  And 
> if I cannot 
> decrypt it, I shouldn't process the message.
> 
> Rgds, Ricky
> 
> At 12:45 PM 12/5/2003 -0600, Cutler, Roger (RogerCutler) wrote:
> >I'm not an expert here, and I was mostly trying to capture 
> the sense of
> 
> >a conversation.  However, I believe that several people 
> agreed that it
> >is, indeed, up to B and C to participate in this decision, 
> and that the
> 
> >"application" envisaged includes both sender and receiver.  This was
> >explicitly stated, I believe, by both David Booth and at least one 
> >other person, I've forgotten whom.
> >
> >About the messageID -- does a SOAP message necessarily have one?  If
> >the intermediary encrypts the message, including the ID, do you have 
> >the same messageID?  It seems to me, from listening and 
> participating 
> >in a certain amount of conversation trying to sharpen up the 
> concept of
> 
> >"same message" that this is a swamp.
> >
> >-----Original Message-----
> >From: Ricky Ho [mailto:riho@cisco.com]
> >Sent: Friday, December 05, 2003 10:49 AM
> >To: Cutler, Roger (RogerCutler); www-ws-arch@w3.org
> >Subject: Re: Intermediaries
> >
> >
> >Can we use messageID to determine whether this is the "SAME" 
> message ?
> >In other words, all other modification is insignificant.
> >
> >1) Intermediary isn't the endpoint so it doesn't generate 
> new messages,
> 
> >so the message it send MUST have same messageID as some previous
> >messages it
> >received.
> >2) Orchestration is the endpoint which produce or consume 
> messages, so
> >the
> >message it send MUST have different messageID from previous received
> >messages
> >
> >Going back to your example, it is NOT up the B and C to 
> interprete the
> >changes made by I differently.  The decision is completely 
> finalized by
> 
> >I.
> >
> >Best regards,
> >Ricky
> >
> >At 09:44 AM 12/5/2003 -0600, Cutler, Roger (RogerCutler) wrote:
> >
> > >Here is some text that expresses my understanding of the sense of
> > >some of the telcon conversation about intermediaries.  Please use, 
> > >modify or
> >
> > >ignor as seems appropriate.
> > >
> > >It is useful to draw a distinction between situations 
> where messages
> > >are passed through intermediaries and choreographies.  The 
> essential 
> > >issue is that an intermediary passes along a message that is 
> > >essentially, or functionally, the same as it received.  If, on the 
> > >other hand, the purpose or function of the message is 
> substantially 
> > >changed one should consider the situation to be a 
> choreography.  This
> 
> > >cannot be defined, however, in an entirely rigorous or black and
> > >white way -- one person's intermediary may legitimately be 
> considered
> 
> > >a choreography by others. Note that since an intermediary 
> can change
> > >the message, for example by encrypting it or by adding ancillary 
> > >information, it remains a judgment call whether those changes are 
> > >significant and functional.  In addition, whether a service that 
> > >passes
> >
> > >messages is considered an intermediary depends on 
> participants in the
> 
> > >entire chain of the message.  For example, if sender A 
> sends messages
> 
> > >through I, which modifies the messages, to receivers B and 
> C, B might
> 
> > >consider the modified message to be functionally unchanged 
> whereas C
> > >might consider it to be different and take different 
> action because 
> > >of the modification.  In the first case I would be considered an 
> > >intermediary, in the second it would not.
> 
> 
> 
> 
> 
> 
Received on Friday, 5 December 2003 15:16:56 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 3 July 2007 12:25:24 GMT