Sequences and sequence sharing

["Pim van der Eijk" <pvde@sonnenglanz.net>]

Hello,

To follow up on the discussion on (re-)using sequences from two weeks ago:
which ebMS messages are sent on the same WSRM sequence? This is more about
ebMS 3.0 in general than about multihop.

Jacques mentioned a default assumption that each Pmode is associated with a
distinct sequence.

1) In the document on routing examples
(http://www.oasis-open.org/apps/org/workgroup/ebxml-msg/document.php?documen
t_id=28981) I discuss a number of routing scenarios. The simplest case
assumes routing is based on To:PartyId only.  It basically asserts for an
I-Cloud that any ebMS message, including messages to be sent reliably, is
handled by the same final MSH.   This means that an ebMS MSH can optimize
its sequence creation, as some Pmodes can use the same sequence. It was
suggested to leave this out of the multihop specification and leave this to
implementers as it is an optimization rather than a potential conformance or
interoperability issue.   

2) Section 2.5 mentions a situation where a message is routed differently
based on a message property value. This means that there have to be
different sequences based only on property values.  Can there be two Pmodes
that are the same except for a particular message property value? If not,
the routing document should not refer to routing based on properties.

3) The ebMS 2.0 message ordering module associates ordering with
ConversationId. Do we want to support a similar model with ebMS 3.0?  If we
have a business process where "conversations" consist of a "PlaceOrder"
action, followed by one or more "ChangeOrder" actions followed by an option
"CancelOrder" action and they are to be processed in order, then the MSH
must use the same sequence to send them.  How and where is this specified?

Pim