Arvola
Setting the ackRequested to Signed or Unsigned is a
decision that the designer (and/or implementer) of the business process makes
when they design or build a business process collaboration or business process
transaction. Factors that need to be considere include
(IMO):
The
natuure of the business process/transaction - e.g. payments probably need to
be secure
The
requirements of the individual trading partners
I
think what would be really useful is to have a guide that describes how to
design a business process/transaction using ebXML Messaging. Do you agree? If so
hould it be in the 1.1 spec or something separate.
I
think that if an error is dicovered then including the ackRequested set to true
on the error message runs the risk of a never ending series of messages. The
only use cases to consider are where a message is being sent reliably in which
case ...
If
the message that was in error has ackRequested set to Signed/Unsigned and the
error message sent in return is lost, then the sender of the original message
will resend it which will cause the error message to be resent - see example 1
below
If
the message that was in error has ackRequested set to None (e.g. it is a
synchronous resposne) then sending the error message with Ack Requested set to
Signed/Unsigned makes sense otherwise the sender of the error message will not
know if the message was delivered - see example 2 below
EXAMPLE 1
Message (with
error)(AckRequested=S/U)---------------------->
<---------------ErrorMessage (Includes
Acknowledgment element)
EXAMPLE 2
Message (no
errors)(AckRequested=S/U)------------------------>
<-------Message (with error) (Includes
Acknowledgment element)
Error Message
(AckRequested=S/U)----------------------------->
<---------------Message (Includes Acknowledgment
element only)
A general rule
(it's somewhere in the spec but I can't immediately find where) says that if you
find an error in an error message then you don't respond with another error
message and sort out the problem by some other means.
Regards
David
-----Original Message-----
From: Arvola Chan
[mailto:]
Sent: Friday, July 27, 2001 7:40
PM
To: ebXML Msg
Cc:
Subject:
T2: ackRequested attribute in Via element
Section 8.7 does not clearly indicate the
circumstances under which the ackRequested attribute should be set (to Signed
or Unsigned). Is this governed by the ReliableMessaging and NonRepudiation
element for the DocExchange associated with the DeliveryChannel that is being
used?
In particular, when an error is encountered in
processing a message, what should be the strategy for setting the ackRequested
attribute in the error message? In other words, under what circumstances, if
any, are error messages to be sent reliably?
Thanks,
-Arvola
