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RE: Snapshot of Web Services Glossary

From: Ugo Corda <UCorda@SeeBeyond.com>
Date: Mon, 24 Feb 2003 12:49:30 -0800
Message-ID: <EDDE2977F3D216428E903370E3EBDDC90819F8@MAIL01.stc.com>
To: "Cutler, Roger (RogerCutler)" <RogerCutler@chevrontexaco.com>, "Walden Mathews" <waldenm@optonline.net>, <www-ws-arch@w3.org>

I just noticed that, interestingly enough, the request-acknowledgement sequence in a reliable messaging context can also lend itself to synchronous or asynchronous interactions, even within the same type of transport binding. Please take a look at WS-Reliability section 5, "HTTP binding", and the diagrams for the various synchronous and asynchronous sequences.

Ugo

> -----Original Message-----
> From: Ugo Corda 
> Sent: Monday, February 24, 2003 12:34 PM
> To: Cutler, Roger (RogerCutler); Walden Mathews; www-ws-arch@w3.org
> Subject: RE: Snapshot of Web Services Glossary
> 
> 
> 
> I think part of the difficulty here is trying to define 
> synchronous and asynchronous the same way across different 
> levels. As Assaf said in a previous note, synchronous and 
> asynchronous can have different specific meanings depending 
> on the scope/layer/context we are referring to. 
> In our case, we should give a definition that applies at the 
> level I would roughly call the SOAP level. Not at the 
> transport/transfer level. Not at the choreography level. 
> That's the level I had in mind when I sent out [1]. 
> 
> > Sooooo -- I am really wondering how one can make an 
> > asynchronous message
> > out of synchronous components.
> 
> The usual example is two HTTP requests making up a single 
> request-response interaction. I think everybody agrees that 
> HTTP is a synchronous protocol at the transport/transfer 
> level. Nevertheless, the whole interaction would be 
> asynchronous at the SOAP request-response level if you 
> follows a definition like the one I gave at [1]..
> 
> Ugo
> 
> [1] http://lists.w3.org/Archives/Public/www-ws-arch/2003Feb/0261.html
> 
> 
> > -----Original Message-----
> > From: Cutler, Roger (RogerCutler) 
> > [mailto:RogerCutler@chevrontexaco.com]
> > Sent: Monday, February 24, 2003 12:25 PM
> > To: Walden Mathews; Ugo Corda; www-ws-arch@w3.org
> > Subject: RE: Snapshot of Web Services Glossary
> > 
> > 
> > That's a really good idea.  Using your suggestions from
> > http://lists.w3.org/Archives/Public/www-ws-arch/2003Feb/0300.html:
> > 
> > If synchronous means "blocking", then it you block you block -- you
> > cannot create an unblocked interaction out of blocking 
> interactions --
> > so under that meaning you can't build an asynch out of synch's.
> > 
> > If synchronous means solicited, then again I don't see how one can
> > combine solicited messages to create an unsolicited one.
> > 
> > If, however, synchronous means "relatively short time" (which most
> > people on this thread seem to think is not a good idea), 
> then I guess
> > you can put together a bunch of messages that take a short 
> time into a
> > whole that takes a long time.  This seems, however, 
> relatively trivial
> > and maybe it illustrates why people don't seem to like the 
> > "short time"
> > approach.
> > 
> > Even if you go to Mr. Arkin's rather formal definition which, if I
> > understand it, says that a message is synchronous if it is 
> > possible for
> > people on the two ends to agree what time it is -- it still 
> > seems to me
> > that if you compose a message out of a bunch of messages 
> > where you know
> > what time it is, in the composite it still should be possible 
> > to figure
> > out what time it is.
> > 
> > Sooooo -- I am really wondering how one can make an 
> > asynchronous message
> > out of synchronous components.
> > 
> > -----Original Message-----
> > From: Walden Mathews [mailto:waldenm@optonline.net] 
> > Sent: Monday, February 24, 2003 1:48 PM
> > To: Ugo Corda; Cutler, Roger (RogerCutler); www-ws-arch@w3.org
> > Subject: Re: Snapshot of Web Services Glossary
> > 
> > 
> > Er, especially if no one agrees on what these terms actually 
> > mean.  Ugo,
> > would it be possible for you to restate what you said below without
> > using either 'synch' term?  Maybe if each of us tried that 
> > once or twice
> > we might get to a better place?
> > 
> > WM
> > 
> > ----- Original Message -----
> > From: "Ugo Corda" <UCorda@SeeBeyond.com>
> > To: "Cutler, Roger (RogerCutler)" <RogerCutler@chevrontexaco.com>;
> > <www-ws-arch@w3.org>
> > Sent: Monday, February 24, 2003 1:38 PM
> > Subject: RE: Snapshot of Web Services Glossary
> > 
> > 
> > >
> > > >Incidentally, in one of the earlier go-arounds on this subject I 
> > > >believe that it was pointed out that one can build a synchronous 
> > > >interaction out of asynchronous components.
> > >
> > > And vice-versa, one could build an asynchronous interaction out of
> > synchronous components.
> > >
> > > Ugo
> > >
> > >
> > >
> > 
> > 
> > 
> > 
> 
> 
Received on Monday, 24 February 2003 15:50:01 GMT

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