RE: Reliable Messaging: Division of Responsibilities (was RE: RES T, Conversations and Reliability)

OK, nobody has picked this up and even though I don't think I am the best
person to do it, let me try to say what I think reliable messaging is.

Reliable messaging is a protocol for sending and receiving messages over the
web which, if followed by all participants in the messaging, will reduce the
uncertainty of the message transmission to a practically acceptable level.
More specifically, if A sends a "reliable message" to B, who is not
necessarily expecting a message at a particular time, A may be assured that
the process will terminate (usually after a known time interval) in one of
three states.  The reliable messaging protocol attempts to maximize the
probability of the first state and minimize that of the third state.

State 1: The message has been received by B and a confirmation has been sent
back to A.  Both A and B agree that the message has been successfully
received.  (An elaboration of this is that B may send a confirmation message
back to A that the message has been received but that it was "damaged in
transit").

State 2: The message has not been received by B.  Both A and B agree that no
message has been successfully received.

State 3: The message has been received by B but A does not know it.

I think that I am positioning this definition in the application layer,
which is more or less where I personally think that the mechanism belongs.

-----Original Message-----
From: Dave Hollander [mailto:dmh@contivo.com] 
Sent: Friday, August 09, 2002 9:10 AM
To: www-ws-arch@w3.org
Subject: RE: Reliable Messaging: Division of Responsibilities (was RE: RES
T, Conversations and Reliability)




yes please do. The definition is part of what I intended in item 3.

dave
-----Original Message-----
From: Cutler, Roger (RogerCutler) [mailto:RogerCutler@ChevronTexaco.com]
Sent: Thursday, August 08, 2002 3:53 PM
To: 'Dave Hollander'; www-ws-arch@w3.org
Subject: RE: Reliable Messaging: Division of Responsibilities (was RE: RES
T, Conversations and Reliability)


Is it possible that we could also contribute to defining what "reliable
messaging" means and what one can expect from it, possibly correlated
somehow with these layers?  I say this because I am convinced that the ebXML
reliable messaging spec is flawed by seeming to offer something that is
actually impossible and by not explicitly recognizing an exception scenario
that can occur under their spec. 

-----Original Message-----
From: Dave Hollander [mailto:dmh@contivo.com] 
Sent: Thursday, August 08, 2002 4:38 PM
To: www-ws-arch@w3.org
Subject: RE: Reliable Messaging: Division of Responsibilities (was RE: RES
T, Conversations and Reliability)



As a WG member...

>> *If* we assume that the view that applications must share *some*
>> responsibility for reliability, then I think our task is to add as 
>> many semantics and formalized processes to access and manage these 
>> semantics.
>
> Can you elaborate on what you mean by that?  I don't understand.

Thanks for the support and I will try to be more specific. 

Assumptions:
1) basic layered architecture: transport, application
	(Pick what ever words work for you, these are the labels I
	am most comfortable with.)
2) intermediaries may be part of a layer or may represent their a
	new one---I am not debating that at this time.

3) an interesting and significant part of an architecture is to
	+ describe the roles and responsibilities for the layers
	+ describe how they interact

Proposed work items:

1) create strawman for layers (or equivalent)
2) place intermediaries in one (or more) locations in the arch
3) describe reliability as it relates the layers
4) identify roles and responsibilities relative to the layers. etc.

Clearly, there will be several models of what reliability is and how to
achieve it. SOAP, REST and all the other perspectives will need to be
considered. But at least when we are done it will be more constructive than
simply agreeing to disagree.

Dave H

-----Original Message-----
From: Mark Baker [mailto:distobj@acm.org]
Sent: Thursday, August 08, 2002 12:16 PM
To: Dave Hollander
Cc: www-ws-arch@w3.org
Subject: Re: Reliable Messaging: Division of Responsibilities (was RE: REST,
C onversations and Reliability)


Dave,

On Thu, Aug 08, 2002 at 10:51:08AM -0700, Dave Hollander wrote:
> The REST, Conversations and reliability thread has been informative. I
> am splitting out what I believe to be one of the key design issues to 
> come from it in hopes of focusing and progressing to a useful 
> architecture document.

Good idea.

> *If* we assume that the view that applications must share *some*
> responsibility for reliability, then I think our task is to add as 
> many semantics and formalized processes to access and manage these 
> semantics.

Can you elaborate on what you mean by that?  I don't understand.

MB
-- 
Mark Baker, CTO, Idokorro Mobile (formerly Planetfred)
Ottawa, Ontario, CANADA.               distobj@acm.org
http://www.markbaker.ca        http://www.idokorro.com

Received on Thursday, 15 August 2002 14:24:58 UTC