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RE: Intermediaries

From: Ugo Corda <UCorda@SeeBeyond.com>
Date: Fri, 5 Dec 2003 13:04:14 -0800
Message-ID: <EDDE2977F3D216428E903370E3EBDDC9039587AF@MAIL01.stc.com>
To: "Francis McCabe" <fgm@fla.fujitsu.com>, "Cutler, Roger (RogerCutler)" <RogerCutler@chevrontexaco.com>
Cc: <www-ws-arch@w3.org>

> (And so, I believe, has WS-I)

WS-I is addressing intermediaries in the Security Profile, but not in the Basic Profile. In some way it was inevitable for WS-I to consider the security implications of intermediaries: the rationale usually given for introducing message-level security is the existence of intermediaries along the message path.

Ugo

> -----Original Message-----
> From: Francis McCabe [mailto:fgm@fla.fujitsu.com]
> Sent: Friday, December 05, 2003 12:57 PM
> To: Cutler, Roger (RogerCutler)
> Cc: Ugo Corda; www-ws-arch@w3.org
> Subject: Re: Intermediaries
> 
> 
> Oh yes, I agree with that.
> However, the problems of building large scale systems are not 
> going to 
> disappear with the working group! So, I am not arguing for actually 
> solving these issues; but I am trying to put things into their proper 
> context.
> 
> It would be easy to simply discard intermediaries. After all, 
> WSDL has! 
> (And so, I believe, has WS-I)
> 
> In any case, I am not really raising problems. There *are* problems 
> with the picture around intermediaries (and a few other 
> places too :) I 
> think that putting them into a proper context will allow us to decide 
> whether to ignore them, raise their profile, whatever.
> 
> Frank
> 
> On Dec 5, 2003, at 12:37 PM, Cutler, Roger (RogerCutler) wrote:
> 
> > Yes -- is it possible that the issues that you are trying 
> to raise with
> > respect to intermediaries are beyond a reasonable scope for 
> the present
> > effort, given the practical limitations of time and personnel?
> >
> > -----Original Message-----
> > From: www-ws-arch-request@w3.org 
> [mailto:www-ws-arch-request@w3.org] On
> > Behalf Of Ugo Corda
> > Sent: Friday, December 05, 2003 2:34 PM
> > To: Francis McCabe
> > Cc: www-ws-arch@w3.org
> > Subject: RE: Intermediaries
> >
> >
> >
> > Frank,
> > I doubt we are going to solve that problem in the little more than a
> > month left ...
> >
> > Ugo
> >
> >> -----Original Message-----
> >> From: Francis McCabe [mailto:fgm@fla.fujitsu.com]
> >> Sent: Friday, December 05, 2003 12:30 PM
> >> To: Ugo Corda
> >> Cc: <www-ws-arch@w3.org>
> >> Subject: Re: Intermediaries
> >>
> >>
> >> I kind of take a mild exception to this Ugo. I don't think 
> it is fair
> >> to say that I am try to "satisfy my philosophical interests" with
> >> computer technologies.
> >>
> >> I am banging on quite a lot about intermediaries because I 
> think that
> >> it represents a way into a very difficult problem: how to actually
> >> build large scale systems.
> >>
> >> Frank
> >>
> >>
> >> On Dec 5, 2003, at 12:16 PM, Ugo Corda wrote:
> >>
> >>>
> >>> 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 16:07:30 GMT

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