Re: T2 PLEAE READ - Suggested solution to RM Issues

[Martin W Sachs <mwsachs@us.ibm.com>]

Chris,

I may be repeating something I already said before seeing your posting, but
let me say it again.  IBM MQSeries is a stack of middleware that includes
much more function that just getting messages on and off the wire.  Since
for MQSeries reliable messaging purposes, each node on the path has the
whole stack, it is only necessary to postulate that all the nodes are
MQSeries, which implies the full set of function. With ebXML, we cannot
make silent assumptions about what is above the MSH, especially with an
intermediary.  We must make explicit statements about what must be there
for reliable messaging to work.  It may be as simple as the statement in
the IBM HTTPR proposal, that intermediaries are assumed to store and
forward reliably, or more may need to be said, especially about non-ebXML
links in the path.

Regards,
Marty

*************************************************************************************

Martin W. Sachs
IBM T. J. Watson Research Center
P. O. B. 704
Yorktown Hts, NY 10598
914-784-7287;  IBM tie line 863-7287
Notes address:  Martin W Sachs/Watson/IBM
Internet address:  mwsachs @ us.ibm.com
*************************************************************************************



christopher ferris <chris.ferris@east.sun.com> on 09/09/2001 09:19:51 PM

To:   Martin W Sachs/Watson/IBM@IBMUS
cc:   "ebXML Messaging (E-mail)" <ebxml-msg@lists.oasis-open.org>
Subject:  Re: T2 PLEAE READ - Suggested solution to RM Issues



I don't see how this is different. See Dan W's email. If all
nodes are ebXML MSH nodes, how is that different than if
all nodes were MQSeries nodes?

IMO, the responsibility of ALL ebXML MSH nodes in a message
path that is carrying a message with OnceAndOnlyOnce
deliverySemantics is to ensure that each node adopts the
semantics implied by that QOS. How they handle the RM semantics
between successive nodes is not relevant save between the two
adjacent nodes.

Cheers,

Chris

Martin W Sachs wrote:
>
> Regarding this statement,
>
>     MQSeries provides an application-level api that can be
>    used to send a DR, but it is optional. That doesn't make MQSeries any
>    less reliable. MQSeries nodes only concern themselves with ensuring
that
>    the
>    message is safely persisted in the adjacent node/queue.
>
> Let's be  careful.  IBM MQSeries is a proprietary protocol and
> implementation that assumes, at least for the purposes of reliable
> messaging, that all nodes on the path have it.  That enables it to
> guarantee exactlyOnce delivery with a minumum of fuss.
>
> ebXML does not have the luxury of that assumption.  We can't make any
> assumptions on the implementations of any of the nodes. We have to make
> crystal clear what are the responsibilities of intermediate nodes to
assure
> that reliable delivery goes all the way down the path.  Some assurance
that
> the message got there helps considerably for this open system.
>
> Regards,
> Marty
>
>
*************************************************************************************

>
>    Martin W. Sachs
>    IBM T. J. Watson Research Center
>    P. O. B. 704
>    Yorktown Hts, NY 10598
>    914-784-7287;  IBM tie line 863-7287
>    Notes address:  Martin W Sachs/Watson/IBM
>    Internet address:  mwsachs @ us.ibm.com
>
*************************************************************************************

>
> christopher ferris <chris.ferris@east.sun.com>@Sun.COM on 09/07/2001
> 04:55:26 PM
>
> Sent by:  Chris.Ferris@Sun.COM
>
> To:   "ebXML Messaging (E-mail)" <ebxml-msg@lists.oasis-open.org>
> cc:
> Subject:  RE: T2 PLEAE READ - Suggested solution to RM Issues
>
> Phew this thread is getting long;-)
>
> Amazingly enough, DB agrees with me on a majority of
> my points... Someone please check for pods in David's
> office!!!
>
> More comments below. I won't <snip/> as this is a valuable
> artifact for the resolution of these issues.
>
> My comments with <cf1/> this go.
>
> Cheers,
>
> Chris
> -----------------------------------------------------
> Chris
>
> Changea 4 & 5 suggest "Make the return of a Delivery Receipt required if
> deliverySemantics=OnceAndOnlyOnce"
>
> Arvola and David F agree with this whereas Chris Ferris disagrees. I can
> see
> benefits in both approaches. So I think we should talk about this on next
> Monday's conference call.
>
> See other comments below marked with <db1></db1> to distinguish from
> earlier
> comments.
>
> David
>
> -----Original Message-----
> From: christopher ferris [mailto:chris.ferris@east.sun.com]
> Sent: Friday, September 07, 2001 11:34 AM
> To: ebXML Messaging (E-mail)
> Subject: Re: T2 PLEAE READ - Suggested solution to RM Issues
>
> My turn;-)
>
> Please see my comments below.
>
> Cheers,
>
> Chris
>
> "Burdett, David" wrote:
> >
> > Arvola
> >
> > See comments in line.
> >
> > David
> >
> > -----Original Message-----
> > From: Arvola Chan [mailto:arvola@tibco.com]
> > Sent: Thursday, September 06, 2001 4:47 PM
> > To: ebXML Messaging (E-mail)
> > Subject: Re: T2 PLEAE READ - Suggested solution to RM Issues
> >
> > David and David:
> >
> > I don't have any major objection to the proposed changes.
> > My comments are in tandem with David Fischer's bracketed
> > by <ac> and </ac>.
> >
> > Regards,
> > -Arvola
> >
> > -----Original Message-----
> > From: David Fischer <david@drummondgroup.com>
> > To: Burdett, David <david.burdett@commerceone.com>; ebXML Messaging
> (E-mail)
> > <ebxml-msg@lists.oasis-open.org>
> > Date: Thursday, September 06, 2001 3:19 PM
> > Subject: RE: T2 PLEAE READ - Suggested solution to RM Issues
> >
> > David,
> >
> > Looks pretty good.
> > <df>Comments inline</df>
> >
> > Regards,
> >
> > David.
> >
> > -----Original Message-----
> > From: Burdett, David [mailto:david.burdett@commerceone.com]
> > Sent: Thursday, September 06, 2001 1:44 PM
> > To: ebXML Messaging (E-mail)
> > Subject: T2 PLEAE READ - Suggested solution to RM Issues
> >
> > Folks
> >
> > If you do not respond to this email then, as chair of the T2 effort, I
AM
> > GOING TO ASSUME YOUR SUPPORT. So please read at least the first part of
> this
> > email which explains why I am doing this ...
> >
> > There has been a LOT of discussion about Reliable Messaging on the
list.
> I
> > also sense that different people's views are gradually aligning.
However
> to
> > move forward we HAVE to come up with constructive suggestions. I first
> did
> > this a nearly a month ago see ...
> >
> > http://lists.oasis-open.org/archives/ebxml-msg/200108/msg00125.html
> >
> > Although there were a lot of replies to this email few of them were
about
> > the actual suggestions I made. Those that were received (Arvola Chan &
> David
> > Fischer) were generally in agreement although both suggested worthwhile
> > improvements. So in order to focus on the solution I have restated the
> > approach in my earlier email below with a few tweaks to reflect more
> recent
> > discussions.
> >
> > What I think will be really constructive is if we use this suggested
> > solution as the basis for discussion so that we can refine it and
> hopefully
> > finalize it in the F2F on October 3-5. Once we get agreement we can
then
> > start making changes.
> >
> > Furthermore, AS CHAIR OF THE T2 EFFORT I AM GOING TO ASSUME THAT NO
> COMMENT
> > MEANS ACCEPTANCE. I don't like doing this but unless we start talking
> about
> > solutions rather than problems we will not make progress.
> >
> > Does this makes sense?
> >
> > Finally, I've missed some of the detail of the discussions in order to
> make
> > the suggested solution (fairly) brief. This does not mean they are not
> > included ... they definitely will need to be ... and if they are
> important,
> > I am sure you will make your views known ;)
> >
> > Best wishes to everyone.
> >
> > David
> > SUGGESTED CHANGES TO SOLVE RM ISSUES
> >
> > Change 1
> > --------
> > Summary: Rename the Via element as "Next Actor Data" or similar.
> >
> > Rationale: There can always be "intermediaries" in a message transfer
> even
> > if you are going point-to-point. For example consider the two example
> > message flows that I recently posted that cover the following use
cases:
> > 1. A genuine intermediary who is a third party that is running a MSH
and
> > forwards messages to the final destination.
> > 2. A Party which has a MSH that acts as a "mailroom" that forwards the
> > message internally using ebXML RM to another MSH that then forwards it
to
> > the application. The "mailroom" MSH ia an intermediary. Chris Ferris
> > provided an example of this use case at
> > http://lists.oasis-open.org/archives/ebxml-msg/200108/msg00412.html
> >
> > I think we need to support both use cases. By renaming the Via element
as
> > "Next Actor Data". We are simply saying that the data contained within
> the
> > element is for the Next Actor **only** and does not need to be
forwarded.
> > The Next Actor recreates the data as they need to if they are
forwarding
> the
> > message. If we think of the data in the Via as being for the "Next
Actor"
> > then we are also more closely aligned with SOAP. It also removes the
> problem
> > of treating intermediaries as "something special" and allows an
internal
> MSH
> > to forward the message to another MSH without the original sender
needing
> to
> > know and without having to re-create the complete message.
> >
> > <df>I agree with all your rationale.  My only question is backward
> > compatibility
> > issues with 1.0 implementations due to the name changes.</df>
>
> <cf>
> I agree that the name change seems arbitrary and should only be taken
> after careful consideration of any backwards-compatibility issues.
> </cf>
> <db1>I've just re-read the spec on Via and, as currently defined it does
> not
> talk about it being used with intermediaries. So we do not HAVE to change
> the name. I just think it is misleading. Perhaps we should vote on this
> one.</db1>
>
> <cf1>
> I don't necessarily agree that the name needs to be changed, but it could
> be tightened up to speifically indicate that it is for use with
> intermediaries
> which is, after all is said and done, what we had in mind when we added
it
> in the 11th hour. As we discussed off-line, I think that much of the
> problems
> that people raise w/r/t 1.0 have more to do with what is NOT said in the
> spec which those of us who were intimately involved in its creation had
> internalized over the course of the discussions, f2f meetings, etc.
>
> IIRC, you were the one who suggested the Via name in the first place! ;-)
> </cf1>
>
> >
> > <ac>
> > I am ambivalent about the name change. Clarification of the intent of
the
> > element and its usage rule is sufficient for me.
> > </ac>
> > <db>We might need to vote on this.</db>
>
> <cf>
> My take is that lumping *all* of the stuff designated for the "next"
actor
> would be a mistake. We should be leveraging SOAP as it is intended. IMO,
a
> SOAP "block" or header should have a specific purpose. More comments on
> this below.
> </cf>
> <db1>Following on from our separate earlier discussions, I think I agree
> with you.</db1>
> >
> > Change 2
> > --------
> > Summary: Data in the Next Actor Data (Via) element is for the Next
Actor
> > only
> >
> > Rationale: What Change 1 means is that we must carefully review the
> existing
> > elements in the header and check to see whether they are needed by the
> > ultimate destination/endpoint or the next actor. I think that this will
> > require the following changes:
> > 1. CPAId. The CPAId in the Message Header identifies parameters that
> apply
> > "end-to-end", e.g. business process level stuff, whereas the CPAId in
the
> > NAD/Via element applies to the transport over a single hop, e.g.
> transport
> > level stuff. I realise this will require changes to the CPP/A ... and
> > probably more discussion.
> >
> > <df>Agreed.  This may not require any CPA change at all since, as Marty
> put
> > it,
> > multi-hop is just a set of binary collaborations.  There is a CPA with
> the
> > end
> > and a CPA with the next hop.  This is perfect.  What is the value if
> there
> > is no
> > IM?  Needs to be optional or allowed to be empty.</df>
> >
> > <ac>
> > I agree with David Fischer.
> > </ac>
>
> <cf>
> As I believe David B has pointed out, the CPAId in the Via element is
> currently optional in the v1.0 spec.
> </cf>
> <db1>Yes, but I think we need to clarify what the presence of the CPAId
> element actually means.</db1>
>
> <cf1>
> No argument here!
> </cf1>
>
> >
> > 2. Acknowledgment Element. This should be part of the NAD/Via element
as
> > acknowledgments are between two MSHs and are not propogated to the
> original
> > sending party.
> >
> > <df>No, if we move Acknowledgement to Via then we remove it from the
> > Signature.
> > This is OK if we don't want signed Acknowledgements.
> >
> > <ac>
> > I suppose it is possible that the CPA between two intermediate MSH
> > calls for non repudiation of receipt in which case the Acknowledgement
> > would have to be signed. I vote for keeping the Acknowledgement
> > element outside of the Via element.
> > </ac>
> > <db>I agree with this also and have withdrawn this suggested
change.</db>
>
> <cf>
> Agree that Acknowledgment, which is already targetted at the "next" actor
> should remain as a separate SOAP header block as per the v1.0 spec.
> </cf>
>
> >
> > If we are going to make this massive a change, then let's go all the
way
> and
> > move TraceHeaderList to Via and simplify the ds:Signature Transform.
> > TraceHeaderList must be modified by each hop and then passed to the
next.
> > TraceHeaderList is intended for the next hop so it also should be part
of
> > Via.
> >
> > <ac>
> > I agree that it makes logical sense to move the TraceHeaderList
> > under the Via/NAD element.
> > </ac>
> > <db>I've a change of view here in that we should not move it unless
there
> is
> > a real reason. We just need to make it clear what the "next" and "to"
> actors
> > need to do with each SOAP extension</db>
> > </df>
>
> <cf>
> The TraceHeader list is already targetted at the 'next' actor. I see no
> reason whatsoever to relocate it.
> </cf>
> <db1>I agree.</db1>
>
> >
> > Change 3
> > --------
> > Summary: Make Next Actor Data (was Via) a required element.
> >
> > Rationale: There are two reasons for this:
> > 1. The current Via element contains data that is REQUIRED for
> > point-to-point, e.g. ReliableMessagingMethod.
>
> <cf>
> If you have a CPA, whether real or imagined, and no intermediary then
> ReliableMessagingMethod is not needed in the message itself. The two
nodes
> already have an understanding as to how they are effecting RM as per
their
> agreement. Thus, it is not REQUIRED for point-to-point RM at all.
> </cf>
> <db1>It's not required if you are using the default values for: syncReply
> (false), reliableMessagingMethod (ebXML), CPAId (use the message level
> CPA).
> If you are not then it IS required whether you are doing point-to-point
or
> multi-hop. This was my main reason for suggesting changing the name from
> Via
> to NextActorData.</db1>
>
> <cf1>
> I disagree. Please be specific as to why you think this is needed. The
> CPA provides the requisite information that the two partys need without
> having to put this in the MessageHeader.
> </cf1>
>
> > 2. There are two levels of reliability, that need to be covered:
> > point-to-point (P2P) as well as end-to-end (E2E).
>
> <cf>
> The fact that the parties agree to exchange receipts is orthogonal
> to RM. The fact that the RM protocol that is defined by the spec
> uses Acknowledgments is mere coincidence. We could have employed
> other mechanisms to acheive reliability. If it is desired that
> there be a formal expression of the equivalent of "I expect an
> acknowledgement" in the SOAP envelope, targetted at the "next"
> actor with a mustUnderstand=1, I suppose I have no problem with
> that. I would prefer that it be a standalone SOAP header and not
> merely lumped in with a bunch of other stuff.
> </cf>
> <db1>I agree that the need for a receipt and the need to do RM are
separate
> requirements. In the current spec an "Acknowledgement message" at a
minimum
> must contain a RefToMessageId that identifies the message that was
received
> (lines 1814-5). The Acknowledgement elementis optional (lines 1816-7) and
> is
> controlled by the ackRequested attribute. I think that the current spec
> meets your need for separation. </db1>
> <cf1>
> ackRequested attribute is only on Via. I would actually prefer the
> solution/proposal
> I offered below to cover all cases, which I think is where you
> were going with this NAD proposal. I would prefer that it be
> a separate SOAP block if it is determined that a majority agree
> that the equivalent of 'ackRequested' is needed/desired in all cases.
> </cf1>
>
> >
> > Currently Via is optional. If we are doing point-to-point, then you
would
> > have to have ReliableMessagingMethod duplicated at the header level in
> order
> > to solve the problem. This does not make sense. Making NAD required
> solves
> > this problem.
>
> <cf>
> See above, I disagree with the assertion that ReliableMessagingMethod
> is required in the MessageHeader.
> </cf>
> <db1>I agree. I don't want ReliableMessagingMethod in the header either.
> See
> earlier response.</db1>
>
> >
> > The layering problem of P2P vs E2E is similar to the problem that
TCP/IP
> > solves as was clearly stated by Dan Weinreb at
> > http://lists.oasis-open.org/archives/ebxml-msg/200108/msg00225.html.
> Marty
> > Sachs, David Fischer and others have also repeatedly said that unless
you
> > have end-to-end acknowledgement then there is no certainty. I think we
> need
> > to recognize that there can always be two levels and therefore need to
> > recognize both these levels in the header.
> >
> > Now TCP/IP does this as two SEPARATE layers. The current spec puts both
> > layers in one spec with one header. I don't think we NEED to radically
> > change the spec in this area but would like peoples views.
> >
> > <df>Agreed.  What is the value of Via CPAId if there is no IM?</df>
> >
> > <ac>
> > The CPAId under the Via element is optional according to the XSD.
> > If the QOS is BestEffort and no intermediary MSH is involved, there
> > is no need for the Via/NAD element. I think it can remain optional as
> > long as we can clearly articulate the circumstances under which it must
> > be present.
> > </ac>
> > <db>Not sure this works. There are additional attributes in the NAD
(Via)
> > element that are currently required such as syncReply. Arvola. Can you
> ckeck
> > the spec and determine which is optional which is required and specify
> what
> > the default semantic should be for each of these elements/attributes if
> the
> > NAD/Via is not present.</db>
> >
> > Change 4
> > --------
> > Summary: Make the return of a Delivery Receipt required if
> > deliverySemantics=OnceAndOnlyOnce
> >
> > <df>Agreed</df>
> >
> > <ac>
> > I agree. Even if the incoming reliable message does not have
> > the DeliveryReceiptRequested attribute set, the receiver MSH
> > should still return a DeliveryReceipt.
> > </ac>
> > <db>I agree but is should be unsigned. This is the default value. See
> > below.</db>
>
> <cf>
> I disagree! As I have repeatedly stated, the delivery receipt is
> not a function of RM. Do not tie the two together. If you want a
>
> deliveryReceipt, then ask for it using the existing mechanism
> (deliveryReceiptRequested). If you want that whenever you send a
> message with OnceAndOnlyOnce you ask for a deliveryReceipt, be my guest.
>
> Please, do not make this a requirement.
> </cf>
> <db1>I think I can see benefits in both approaches. If we make it a
> requirement then it should make for a simpler solution at the expense of
> doing it even when it is not always needed. I think this is one we need
to
> discuss on a conference call.</db1>
> <cf1>
> 'fraid I won't be able to join the next call (Monday). I don't think
> that it actaully makes anything simpler. I request that the discussion
> of making it a default/required be deferred until I can participate.
> </cf1>
>
> >
> > Change 5
> > --------
> > Summary: Remove "None" as an option for deliveryReceiptRequested and
make
> > deliveryReceiptRequested=false the default.
> >
> > Rationale: As the return of a Delivery Receipt is the only sure way
that
> you
> > know a message was delivered suggests that it will be a simpler
solution
> if
> > we make this always the case. Therefore we can make the return of a
> delivery
> > required if the deliverySemantics are OnceAndOnlyOnce. However you
still
> > need to know if the receipt must be signed.
> >
> > <df>Agree with removing "None" but would prefer to leave as "Signed |
> > Unsigned"
> > for backward compatibility.  Default is "Unsigned".</df>
> >
> > <ac>
> > I agree with David Fischer.
> > </ac>
> > <db>So did I!</db>
>
> <cf>
> Again, as I disagree with making a DR REQUIRED, I see no real value
> add in changing "None" to "false" unless the DR is ALWAYS signed
> in which case making the attribute an XSD boolean would make sense.
> </cf>
>
> >
> > Change 6
> > --------
> > Summary: Make the return of an Acknowledgment element in a message
> required
> > if the ebXML RM protocol is being used
> >
> > <df>Agreed, but isn't this already true?</df>
> >
> > <ac>
> > I agree with David Burdett. The current spec does not required the
> > Acknowledgement element to be present in an Acknowledgement
> > message.
> > </ac>
> > <db>I agree with you and me ;)</db>
>
> <cf>
> Huh? If the issue is that section 10.3.3 is less than clear as to whether
> an "Acknowledgment message" MUST have an Acknowledgment element, then
> clearly, that is an editorial issue that should be addressed. Seems
> to me that lines 1814/1815 should be changed to read:
>
>      At a minimum, it MUST contain a MessageData element with a
>      RefToMessageId that is set to the value of the MessageId of
>      the message being acknowledged along with an Acknowledgment
>      element as described in section 8.6.
> </cf>
> <db1>I think this is the sort of wording we need. It also though makes
> lines
> 1816-17 redundant and removes the need for ackRequested.</db1>
>
> >
> > Change 7
> > --------
> > Summary: Remove "None" as an option for ackRequested and make
> > ackRequested=false the default.
> >
> > Rationale: The rationale for doing this is similar to changes 4 and 5.
It
> > simply gives the rule that if you are doing ebXML RM then you must
> include
> > an Acknowledgment element in the response. The response can be
> synchronous
> > or asynchronous (see change 11 below).
> >
> > <df>Agree with removing "None" but would prefer to leave as "Signed |
> > Unsigned"
> > for backward compatibility.  Default is "Unsigned". (same as Change
> 5)</df>
> >
> > <ac>
> > I agree with David Fischer.
> > </ac>
>
> <cf>
> Actually, consistent with the proposal I put forth above, adding a
> SOAP header block requesting an Acknowledgment would be a bit more
> coherent IMO.
>
> e.g.
>
>      <SOAP:Envelope xmlns:SOAP="...">
>        <SOAP:Header>
>          <eb:MessageHeader xmlns="...">...</eb:MessageHeader>
>          <eb:AckRequested xmlns:eb="..."
>           SOAP:actor="http://.../next"
>           SOAP:mustUnderstand="1"
>           eb:signed="true|false"/>
>        </SOAP:Header>
>        <SOAP:Body>
>          <eb:Manifest xmlns:eb="..">...</eb:Manifest>
>        </SOAP:Body>
>      </SOAP:Envelope>
>
> This approach is more consistent with SOAP and it eliminates the
> need to worry about ReliableMessagingMethod. It also provides for
> the Acknowledgment to be used for a foriegn specification for a reliable
> protocol that also used acknowledgments. For that matter, we could
> consider the AckRequested and Acknowledgment elements to be a
> SOAP module that is useful in and of itself. It could be essentially
> a self contained module with its own set of processing semantics
> specified, etc. IMO, this is a far cleaner and more modular approach.
> </cf>
> <db1>Chris I agree !! But is this a "bugfix" or an "enhancement" and
> therefore version 2.0. I really like it though. It is though inconsistent
> with your earlier suggested change to lines 1814-15.</db1>
> <cf1>
> It is no more of an enhancement than NAD. It isn't necessarily
> inconsistent, but it would be a different means of expressing
> the intent behind saying that an Acknowledgement message must
> have an Acknowledgment element. I'd be more than happy to craft
> this for consideration.
> </cf1>
>
> >
> > Change 8
> > --------
> > Summary: Include automated retry by the original sender (From Party) if
> no
> > Delivery Receipt is returned
> >
> > <df>Agreed</df>
> >
> > <ac>
> > Do we need to give some guideline on the selection of retry interval
> > for hop-to-hop vs retry interval for end-to-end?  I think the former
> > interval
> > should be shorter than the latter.
> > </ac>
> > <db>Agree this would need to be included in the revised spec.</db>
>
> <cf>
> I disagree for the reasons I've repeatedly cited. Absence of a received
> DR does NOT mean that the message hasn't been delivered. It only means
that
> the sending party hasn't received a DR.
>
> I would counter-propose the following:
>
> - REQUIRE that ALL MSH nodes that receive a message with OnceAndOnlyOnce
>   deliverySemantics SHALL comply with the reliable messaging semantics
>   as defined in section 10. Further specify that any MSH node that
>   acts as an intermediary SHALL forward the message onto the next MSH
>   node using reliable messaging semantics as defined in section 10.
>
> - REQUIRE that a DFN SHALL be sent to the From Party (section 10.4)
>   as requested by Marty if a message cannot be delivered.
>
> - Clarify what "cannot be delivered", in section 10.4, means:
>      A message that is sent with deliverySemantics of OnceAndOnlyOnce
>      for which the MSH, after exhausting the specified number of
>      retries, separated by the specified retryInterval, has either
>      been unable to send (e.g. unable to establish a network connection
>      with the designated MSH node to which the message is to be
> delivered)
>      or for which no "Acknowledgment message" has been received.
>
> - REQUIRE that a DR be delivered reliably (OnceAndOnlyOnce) if requested
>
> - add a MSH "parameter" for DRTurnAroundTime or something like that
>   which the sending MSH uses to wait for a DR
>
> - REQUIRE that the From Party's origin MSH notify the "From Party"
>   if the DRTurnAroundTime expires before receiving a DR
>
> - let the "application layer" of software make the determination as
>   to whether or not it wants to resend the message, possibly using
>   an alternate delivery channel.
>
> Please do keep in mind that a NRR/DR SHOULD be supported even if
> the deliverySemantics are BestEffort IMO. Let us not confuse these
> mechanisms.
>
> Adding in the complexity of having to deal with intermediaries
> re-forwarding/processing messages for which no DR has been
> received would be a mistake IMO. It raises the bar on the complexity
> of an MSH considerably, especially for processing intermediaries
> as I have repeatedly pointed out.
>
> If we stick with a store and forward, all nodes must adopt, protocol
> then if a message does not go through, there are WAY bigger problems
> than might be addressed by resending the message in any event.
>
> </cf>
> <db1>Again I generally like the clean separation that your ideas suggest.
> However I have a couple of concerns.
> 1. It assumes a homogenous network where all the hops use ebXML. The real
> world will not be like this for a long time, if ever. However we don't
want
> this to stop people using ebXML RM for some or all of the hops. Also
> suppose
> ebXML only goes as far as the mailroom. What happens after that? I
suggest
> therefore the following as an alternative to your first para ...
>
> "- REQUIRE that ALL MSH nodes that receive a message with OnceAndOnlyOnce
> deliverySemantics SHALL comply with the reliable messaging semantics as
> defined in section 10. Further specify that any MSH node that receives
such
> a message SHALL forward the message onto another MSH node using reliable
> messaging semantics as defined in section 10 or use other processes that
> provide similar degrees of reliability."
>
> <cf1>
> We discussed this in various f2f meetings and we concluded that the
> semantics ONLY applied between MSH nodes. If the message is passed
through
> a pachinko (sp?) machine between MSH nodes, or through orange juice cans
> and strings, the sending MSH is still responsible for ensuring that
> the receiving MSH node gets it. We don't consider what happens
in-between.
> SMTP is a good example. We don't care how SMTP moves the message from one
> end to the other, we only care about the MSH nodes that send and receive
> it.
> </cf1>
>
> 2. I can see the benefit in making re-sends of a message because no DR
has
> been received an application responsibility makes the spec cleaner.
> However:
> a) Marty has said words to the effect that unless you know that the
message
> has been received (ie you have a DR) then you don't have RM.
>
> <cf1>
> I respectfully disagree with Marty. MQSeries provides an
application-level
> api that can be
> used to send a DR, but it is optional. That doesn't make MQSeries any
> less reliable. MQSeries nodes only concern themselves with ensuring that
> the
> message is safely persisted in the adjacent node/queue.
> </cf1>
>
> b) You are increasing the burden on the application layer in that you are
> making it do the retries if an expected DR was not received.
> So if we don't include it in the v1.1 spec should we include it in v 2.0
or
> in a separate spec?
> </db1>
> <cf1>
> This is, IMO, a v2 issue at best, and possibly more of the perview of
> the BSI or BPF than anything MSH related. Again, there are larger
> issues at play here.
> </cf1>
>
> >
> > Change 9
> > --------
> > Summary: Include a "MessageRetryCount" in the NAD (was Via) element in
> the
> > Message Header
> >
> > Rationale: There is a need for automated retry by the original sender
> (From
> > party) if a Delivery Receipt is not received. However, the original
> sender
> > wants to send the **identical** message yet not have it treated as a
> > duplicate and by any intermediate MSH that has previously received it.
To
> > solve this problem you can add a "MessageRetryCount" to the NAD which
> > indicates to the MSH that even though they have received the message
> before
> > they must still forward it.In this case even if the resend is received
> first
> > and the original appears some time later, the ToParty will be able to
> > recognize that the message has already been processed by comparing
> MessagIds
> > only and therefore the original should be ignored. This logic needs to
be
> > included in section 10 and will need to include another level of
> > RetryCounts/RetryIntervals to work at the end-to-end rather than the
> > point-to-point level.
> >
> > <df>Agree on MessageRetryCount.  No need for another level of
> > Retries/RetryInterval since it already exists -- there is one set in
the
> > end-to-end CPA (MessageHeader CPAId) and another in the Sender-FirstHop
> CPA
> > (Via
> > CPAId).</df>
> >
> > <ac>
> > I agree with David Fischer.
> > </ac>
>
> <cf>
> As I said above, this raises the bar on complexity. You cannot use the
> same retries/retryInterval as for single-hop for starters. Consider a
> long chain of intermediaries which may have the ultimate recipient
> receiving
> the message after a significant passage of time for which the sending
> node wants to simply know when to stop resending (or trying to resend)
> the messsage to the first intermediate node.
> </cf>
> <db1>No further comment</db1>
>
> >
> > Ch
 - chris.ferris.vcf