[ebxml-msg] Interaction between AckRequested, DuplicateElimination,and SyncReply elements

I like to address the following question, mostly to folks who have already
implemented ebMS 2.0.

If the sender MSH includes a DuplicateElimination element and a SyncReply
element, but no AckRequested element in an ebXML message, and the receiver
MSH determines that the received message is a duplicate, should it simply do
nothing, as prescribed on line 1681 in the Version 2.0 rev C spec?

The problem of doing nothing is that the sender MSH is waiting for a
synchronous reply. The connection will not get closed until some timeout
parameter kicks in either on the sending or receiving side. This doesn't
seem an efficient way of using network resources. Can "do nothing" be
interpreted as closing the connection, or returning a 200 OK status code and
closing the connection?

-Arvola