David:
We are contemplating the addition of an AckRequested
element and a duplicateElimination attribute to the
Characteristics element under the DeliveryChannel element
to mirror what are carried in the message header.
This AckRequested element will have a signed attribute.
The combination of the duplicateElimination attribute and
the AckRequested element can signal the use of Reliable
Messaging. Thus, if the receiver is expecting Reliable
Messaging to be used for a given channel, it will return
an appropriately signed or unsigned Ack when it receives
an incoming message on that channel.
One further clarification, we are planning to split Characteristics
into two elements: BPCharacteristics to group together
properties that derive from the business process specification,
and MSGCharacteristics to cover the AckRequested element
and the duplicateElimination attribute that are specific to the
messaging service. If DeliveryReceipt and
DeliveryReceiptRequested survive in the 1.1 MSG spec, then
a DeliveryRequested element will also be added to the
MSGCharacteristics element.
If an incoming message carries an AckRequested element
and a duplicateElimination attribute that do not match what's
specified in the CPA, an implementation that strictly follows
the MSG and CPP/A spec should return an Error and stop
processing.
Regards,
-Arvola