Chris:
I agree with you that there will be use cases where a forwarding
intermediary may need to use different transport protocols for inbound and
outbound messages. I believe Dale is assuming that a common CPA will be used
by the From Party, the To Party, and the intermediary/intermediaries. Maybe
that assumption is too restrictive. Even with such an assumption, it is not
clear to me how it can be made to work. Consider the one intermediary case,
if the intermediary's endpoints are transparently used by the From Party and
the To Party as their own endpoints in the CPA (i.e., the transport
endpoints in the CPA all contain addresses associated with the
intermediary), then where does the intermediary find the real forwarding
addresses for the From Party and To Party? Clearly, there is extra
configuration information needed by the intermediary that is missing from
the CPA. I also tend to agree with Marty that once you take into
consideration transport level security or if there are multiple
intermediaries, it will be unwieldy to capture all the relevant
configuration information in one CPA.
Has anyone worked out simple examples where a separate CPA is used between
each adjacent pair of MSH nodes? What kind of business processes have to be
used to represent the message forwarding activities? What Service and Action
elements will be appropriate under the Via element? Is the existing CPP/A
element structure sufficient for this purpose?
Regards,
-Arvola
