RE: [ebxml-msg] Interaction betweenAckRequested,DuplicateElimination,and SyncReply elements

[Dale Moberg <dmoberg@cyclonecommerce.com>]

The behavior that Arvola describes 
(about resending cached business
responses or waiting for one to 
become available)
is described in the section on
resending acknowledgments, 6.5.5.

The presence of DuplicateElimination by itself 
is to implement "At Most Once" delivery (or
so the spec says). Doesn't say it is supposed
to support caching responses and returning
them if a duplicate is received.

I did not interpolate that some sub-behavior from 6.5.5
applied to the DuplicateElimination on its own case.

I think you have to state that explicitly
if that is what the receiving MSH is supposed to do
It is currently not clear from the spec because
as Arvola emphasizes,  the spec. says
to do nothing in the DuplicateElimination by
itself case.


Dale Moberg

-----Original Message-----
From: Doug Bunting [mailto:db134722@iPlanet.com]
Sent: Wednesday, March 27, 2002 2:39 PM
To: ebXML Msg
Subject: Re: [ebxml-msg] Interaction between
AckRequested,DuplicateElimination,and SyncReply elements


Hmmm,

That wasn't my reading of 2.0 rev C.  If others agree it's a possible
reading of
the text, it should be fixed.  I agree with Arvola that duplicate
elimination
and returning a copy of the first response should be triggered by the
DuplicateElimination element.  AckRequested should simply determine
whether or
not that first response includes an Acknowledgment element.

Were others confused?  What change would improve the wording?

thanx,
    doug

Arvola Chan wrote:

> Doug:
>
> In earlier versions of the spec when we had only the concept of
Reliable
> Messaging and not separate control of AckRequested and
DuplicateElimination,
> it was clear that whenever a receiver receives a reliably delivered
message
> that is not a duplicate, it is obligated to at least make a persistent
copy
> of the message ID as well as a persitent copy of the first response
message.
> When a received reliably delivered message is determined to be a
duplicate,
> the receiver is supposed to return the saved first response message.
>
> Now that AckRequested and DuplicateElimination can be controlled
separately,
> it is not clear whether the behavior to save the first response
message and
> to return the saved first response message in reply to a duplicate
message
> is triggered by the AckRequested element or by the
DuplicateElimination
> element.
>
> I would have preferred that the above behavior be triggered by the
> DuplicateElimination element. However, Version 2.0 rev C indicates
that the
> above behavior should only be exhibited by the receiver MSH if the
> AckRequested element is present.
>
> Regards,
> -Arvola
>
> -----Original Message-----
> From: Doug Bunting [mailto:db134722@iPlanet.com]
> Sent: Wednesday, March 27, 2002 11:58 AM
> To: Arvola Chan
> Cc: ebXML Msg
> Subject: Re: [ebxml-msg] Interaction between AckRequested,
> DuplicateElimination,and SyncReply elements
>
> [Please note: Yes, this is still me.  I had to change email addresses
due to
> Yahoo! changes.]
>
> Arvola,
>
> This is a very good point covered slightly by issue 127 and might
touch on
> issues 165-166.  If we must interpret "do nothing" or "ignore", it
should be
> explained in the text or an errata.
>
> In this particular case, the sender isn't waiting for an MSH signal in
> general.
> It should be waiting for the (stored) business response.  (The
duplicated
> elimination flag indicates that response must have been stored.)  The
text
> is
> incomplete around a more specific sub case of what you've described:
when
> CPA
> syncReplyMode="MSH Signals" (or whatever the next level above "none"
is
> called)
> and not a mode involving application information.  With that
clarification,
> the
> original message would also have a problem because no information was
> available
> to reply on the synchronous channel.
>
> The most efficient response when no information is really required
would be
> a
> 200 OK.  Closing the connection would only tell the originator to
start
> retry
> cycles.  However, sending a "real" body (probably, just an ebXML
> MessageHeader
> element) in the synchronous reply could be useful for duplicate
elimination
> cases, allowing the receiver to store something as their response.
>
> thanx,
>     doug
>
> Arvola Chan wrote:
>
> > I like to address the following question, mostly to folks who have
already
> > implemented ebMS 2.0.
> >
> > If the sender MSH includes a DuplicateElimination element and a
SyncReply
> > element, but no AckRequested element in an ebXML message, and the
receiver
> > MSH determines that the received message is a duplicate, should it
simply
> do
> > nothing, as prescribed on line 1681 in the Version 2.0 rev C spec?
> >
> > The problem of doing nothing is that the sender MSH is waiting for a
> > synchronous reply. The connection will not get closed until some
timeout
> > parameter kicks in either on the sending or receiving side. This
doesn't
> > seem an efficient way of using network resources. Can "do nothing"
be
> > interpreted as closing the connection, or returning a 200 OK status
code
> and
> > closing the connection?
> >
> > -Arvola
> >
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