OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.


Help: OASIS Mailing Lists Help | MarkMail Help

ebxml-msg message

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [Elist Home]

Subject: T2 Items August 1 to 10 that are missing from the list you publishedlast week

Here is a retransmission in HTML format.

Request Date: 8/6/2001
Request Source: e-mail
Source Reference: http://lists.oasis-open.org/archives/ebxml-msg/200108/msg00038.html
Change Type: MinorTechnical
Requested By: Cait Crawford
Issue: Reliable Messaging section should be expanded to include the POINT-TO-POINT option where no Via or Acknowledgment elements are used
I have a comments/questions regarding POINT-TO-POINT reliable messaging
implementation for ebXML MS 1.0.
First, lets assume that Party A is sending a message reliably -- that the
deliverySemantics have been set to OnceAndOnlyOnce and
deliveryReceiptRequested to Unsigned (I don't think that Signed/Unsigned
makes a difference for the example, actually) in the QualityOfService
element in the MessageHeader.  I am sending this message w/out
intermediaries, so I am not making use of the Via or Acknowledgment
elements, although I am populating the TraceHeader element as appropriate.
Now, Party B receives the message.  Now assume that there is NO REPLY from
the application.  Party B is required to send an "Acknowledgement Message"
(section 10.3.2) which at a minimum has a MessageData element with a
RefToMessageId of the received message.  Since a deliveryReceipt is also
requested, the MSH must also generate the DeliveryReceipt element in the
ack message.  My question concerns the service and action elements of this
ack.  Clearly, as there is no business-level reply, the service and action
should not reflect any business or application level service & action.  In
section 10.3.3, the spec says that if an Acknowledgment element is being
sent on its own then service MUST be set to:
uri:www.ebxml.org/messageService and action MUST be set to Acknowledgment.
What is the equivalent service/action for a DeliveryReceipt element being
sent on its own?? (as set in the MessageHeader element for this ack
message)??  Is this described in the CPP/BPSS since this is one of the
"signals" that need to be processed by the MSH-application interface??
What would happen if the deliveryReceiptRequested was false, but the
semantics were set to OnceAndOnlyOnce??  The minimal acknowledgement
required only a RefToMessageId within the MessageData element -- any
guidelines as to what should be used in the Service and Action elements in
the MessageHeader?
In general, I think that the Reliable Messaging section should be expanded
to include the POINT-TO-POINT option where no Via or Acknowledgment
elements are used, but deliveryReceiptRequested attributes are turned on.
(i.e. there is no information about whether the reply is sync or not in the
message header).
Request Date: 8/6/2001
Request Source: e-mail
Source Reference: http://lists.oasis-open.org/archives/ebxml-msg/200108/msg00045.html
Change Type: MinorTechnical
Requested By: David Fischer
Issue: SyncReply and ReliableMessagingMethod should also be in QualityOfServiceInfo
There should be nothing in the Via which is not also in other headers.  Via
should only be used for multi-hop intermediaries.  In the case of SyncReply,
there is no single-hop way of requesting SyncReply=true.
Attributes SyncReply and ReliableMessagingMethod should also be in
QualityOfServiceInfo.  They should retain their current defaults.
Request Date: 8/9/2001
Request Source: e-mail
Source Reference: http://lists.oasis-open.org/archives/ebxml-msg/200108/msg00095.html
Change Type: MSG/CPPA Alignment
Requested By: Himagiri Mukkamala
Issue: Schema element in Manifest
Reference element has a schema element in it.
Where does this come from?
I could'nt find it in the CPA from the packaging element?
Request Date: 8/9/2001
Request Source: e-mail
Source Reference: http://lists.oasis-open.org/archives/ebxml-msg/200108/msg00096.html
Change Type: MinorTechnical
Requested By: David Burdett
Issue: Need to change Service and Action for Errors, Delivery Receip ts etc.
I agree that the spec is quite specific. However I think that having just one value for Service and Action for a Delivery Receipt makes it hard a MSH which receives a Delivery Receipt to work out which application to notify. For normal messages, Service and Action contain some useful name, e.g Service=SupplierOrderManagement, Action=NewPurchase order. This can be used to route the message to the application that supports OrderManagement.
On a Delivery Receipt, Service contains "uri:www.ebXML.org/messageService" and Action "DeliveryReceipt" as you quote below and the MSH is given no clue on which application to forward the message to.
This means that the MSH has to look up the original message sent to work out where the DR was sent to.
There is an IDENTICAL problem with Error Messages as the MSH will not know which the application to forward the message to. This time though, it is worse as the message may not have been saved if it was sent with RM as BestEffort. If we don't change the spec then a Sending MSH will have to PERSIST ALL MESSAGES whether sent reliably or not so that they can work out which applicatioon to notify if there is an error.
The better alternative I propose is to make Action hold all the information, e.g.
    Action =uri:www.ebXML.org/messageService/MessageError
Then Service could contain "BuyerOrderManagement" so that the MSH could work out which application to notify of the error. However this requires that you know what to put in the Service when an error or other similar message is returned to the sender of a message. To solve this you also need to specify the Sending "From Service" in the original message.
Request Date: 8/9/2001
Request Source: e-mail
Source Reference: http://lists.oasis-open.org/archives/ebxml-msg/200108/msg00107.html
Change Type: minorTechnical
Requested By: David Smiley
Issue: Use of Message Status Requests
Being relatively new to the ebXML world, but learning more every day, I have
been hesitant to jump in where those even more experienced may fear to
tread, but here I go...
I have extracted a relevant paragraph from the large body of the "T2
SyncReply and ReliableMessagingMethod in
QualityOfServiceI nfo" thread.
<Martin W Sachs>
The problem about this use case is that the intermediary is neither a
participant in the business process nor strictly a
pass through.  I suspect that means that it does participate in the
business process though "not much".
</Martin W Sachs>
From a business perspective, please help me understand how any intermediary
is not a participant in the business process? If they are only a "pass
through", why are they used? If they are involved, but "not much", is that
like being "a little pregnant" ;-)? It seems to me that any party which
handles my business transactions, intelligently, persistently or otherwise,
is part of the business process.
In the discussion of acks, delivery receipts, reliable messaging and floods,
no mention is made of the use of Message Status Requests. I realize that
this capability is optional in the implementation of a Message Service
Handler, but wouldn't it be useful in some of the scenarios mentioned? In
lieu of always resending a message whose delivery status is unknown, use of
Message Status Requests could reduce the number of large messages that are
resent unnecessarily. This may result in a very high tide, but floods may be
Request Date: 8/10/2001
Request Source: e-mail
Source Reference: http://lists.oasis-open.org/archives/ebxml-msg/200108/msg00125.html
Change Type: MajorTechnical
Requested By: David Burdett
Issue: Proposed solution for various issues related to reliable messaging
I have some ideas for a few changes that might solve the problems raised in
this thread so the rest of this email contains:
1. Extracts from a number of recent emails from you both and analysis of the
issues/requirements they raise
2. Some additional further analysis of the issues to identify a few more
3. A proposed solution to meeting the identified requirements which
hopefully will solve the problem ... and who knows perhaps bring this email
thread to an end :-)
So please let me know if:
a) I've missed a requirement
b) You (or anyone else) think the proposed solutiuon is wrong or could be
improved ... but then I know you will anyway ;)
Details below
Arvola Chan: Thu 8/9/2001 3:28 PM
>>I am of the opinion that the DeliveryReceipt element should be used by the
ToParty MSH to inform the FromParty MSH that a reliable message has been
received. ... It is the non-arrival of a DeliveryReceipt that requries the
MSH to notify the application. In this case, it must rely on persistent
information to determine the application service that must be notified.<<
>>I think end to end acknowledgement is always needed to support reliable
messaging, so it is unnecessary to explicitly set deliveryReceiptRequested
to true, it should always be implied by deliverySemantics of
OnceAndOnlyOnce. On the other hand, if intermediary acks are optional, then
ackRequested needs to be an explicit attribute at the QOS level and it
should apply to all intermediaries.<<
[DavidB]This highlights a number of issues/requirements:
Req 1. A positive Ack sent back to the sender of a message by the ultimate
destination is the only sure way the sender can be certain the message was
delivered. If no Delivery Receipt is sent, then the sender cannot be so
Req 2. If end-to-end Delivery Receipts are always required for the sender to
be certain, then it would be simpler if there was a rule that
deliverySemantics of OnceAndOnlyOnce implies a Delivery Receipt is sent. The
only remaining issue is whether or not the Delivery Receipt should be
David Fischer: Thu 8/9/2001 7:31 PM
>>Question 1 ... the end-to-end MUST be able to do RM as if it does not know
(which it probably doesn't) what the IM(s) are doing.  The end-to-end
probably doesn't care if the IM(s) are doing RM at all (even though each IM
might care very much)<<
>>On the issue of Sender time outs and retries, their are two kinds:  1) a
timeout to the first IM and 2) a timeout getting to the end.  The first is
easy and obvious so we don't need to discuss it.  The second is a timeframe
that is usually contractually guaranteed ...<<
>>While the Sender/Receiver may not have any idea what path or IM transport
the message is taking (and they really don't need to) they must have an idea
about delivery times to the end.  We MUST generate some kind of an
end-to-end Ack allowing the ends to do RM.<<
1) We need to update section 10 with end-to-end RM (deliveryReceipt or
something new that is similar to Acknowledgement).
2) We need to put in the spec somewhere that ALL MessageHeaders (including
Via) MUST be passed to the next hop, including the end.<<
>>Question 2 ... I agree that it doesn't matter if ackRequested gets changed
because an Ack gets sent based upon DeliverySemantics (This was my second
solution to Question 2).  Why then do we have ackRequested?  The only way it
would change is if there was some kind of local CPA overriding ackRequested.
If RM is requested and an IM can do RM then it MUST, right?  Then why have
this parameter?  (I see from your comments that you are considering this.)
[DavidB]This highlights a number of issues/requirements:
Req 3. The sender should not know nor care if an IM is being used and
whether or not they are doing RM with the next IM.
Req 4. There are two different types of "acks" that are useful:
  a) It's been accepted by the postal system (i.e. the next MSH has
received, this is the Acknowledgement Message)
  b) It's been received by the final destination (i.e. the To Party has
received it, this is the Delivery Receipt)
Req 5. Even if the initial Ack (i.e. Acknowledgment Message) is received
there needs to be some method of automated retry if the Delivery Receipt is
not received within the expected timeframe.
Req 6. If you a doing reliable messaging between two hops, then you do not
need ackReqeusted as an acknowledgment must be sent if the ebXML RM protocol
is being sent and not needed if it isn't.
David Fischer: Thu 8/9/2001 8:02 PM
>>I am concerned that end-to-end RM is taking a back seat to IM RM.  This is
the opposite of how it should be.  Most transactions will be single-hop.
Many other cases will be single IM where the sender or receiver may not even
know there is an IM so it still appears to be single-hop.  The ends should
not even have to know about the IMs.  Ends will always do automatic retries.
RM should work for the ends in exactly the same manner whether or not there
are IMs.<<
[DavidB]This really just provides further support for issues/requirements
numbered 3 and 5 above.
Arvola Chan: Fri 8/10/2001 12:23 AM
>>Even if you have a channel that calls for the use of synchronous reply
mode, the syncReply attribute still has to be set. In other words, it is
still necessary to use the Via element if the syncReply attribute is present
only there, but this constradicts the assumption that the Via element is
only used when intermediaries are involved.<<
[DavidB]This highlights a number of issues/requirements:
Req 7. The syncReply needs to be set at the message level whether or not an
intermediary is being used
Req 8. There is a contradiction in the spec (which therefore needs to be
removed) that the Via element is only for intermediaries when it is actually
also needed for non-intermediaries.
Before proposing a resolution to all these requirements I'd like to make a
few comments and identify an additional couple of requirements.
Firstly on Requirement 6 above (you don't need ackRequested). There could be
benefit in gettingan acknowledgement element back even if you are using a
reliable messaging protocol such as MQ Series as you then have evidence
(especially if it is signed) that the next MSH has received the message. I'm
not convinced though that this is a huge benefit.
Secondly if we put syncReply at the message level then there is an
additional requirement ...
Req 9. The next recipient of a message needs to know whether or not to
return an acknowledgement message synchronously or not.
Now for the proposed solution.
The solution dsecribed below refers to the requirements identified above ...
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 (also posted here) 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.
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 we think of the data
in the Via as being for the "Next Actor" then we are 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.
This change addresses Req 3 and 8.
Change 2
Summary: Data in the Next Actor Data (Via) element is for the Next Actor
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.
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.
This change addresses Req 3, 4a
Change 3
Summary: Make the return of a Delivery Receipt required if
Change 4
Summary: Replace deliveryReceiptRequested by deliverReceiptSigned=true or
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.
These changes address Reqs 1, 2, 4b
Change 5
Summary: Make the return of an Acknowledgment element in a message required
if the ebXML RM protocol is being used
Change 6
Summary: Replace ackRequested by ackSigned=true or false(the default)
Rationale: The rationale for doing this is similar to changes 3 and 4. 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 9 below).
Change 7
Summary: Include automated retry by the original sender (From Party) if no
Delivery Receipt is returned
Change 8
Summary: Include "ResendOfMessageId" 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
cannot send the **identical** message as it will be treated as a duplicate
and therefore ignored by any intermediate MSH that has previously received
it. To solve this problem the from party needs to use a different MessageId.
However there is now a need to stop the message being treated as a
completely new message. To solve this problem we could add a
"ResendOfMessageId" element that identifies which message the new message is
a resend of. 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 and therefore the original should be
ignored. This logic needs to be included in section 10 and probably needs a
bit more thinking through.
These changes addresses Req 5
Change 9
Summary: Include syncReply at both the Message Header and the NAD/Via
The To Party needs to know whether the From Party wants the Delivery Receipt
and Business Payload assembled into one message.The next MSH needs to know
whether to send back an Acknowledgment synchronously or wait for the
Business Payload before sending it. The Delivery Receipt and Business
Payload can be sent asynchronously and the Acknowledgment sent synchronously
and vice versa as they are independent of each other.
As you can't easily cover both requirements in a single element, they need
to be included separately in the header and in the via.
This change adresses Reqs 7 and 9.
Request Date: 8/10/2001
Request Source: e-mail
Source Reference: http://lists.oasis-open.org/archives/ebxml-msg/200108/msg00127.html
Change Type: Editorial
Requested By: David Fischer
Issue: Inconsistent SERVICE specification
The Service for an Acknowledgement should match between 10.3.2 number 1 and
10.3.3 second bullet set, first bullet.  Action is correct.

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [Elist Home]

Powered by eList eXpress LLC