Regarding Arvola's second paragraph: I believe that the existing content
of the CPA is sufficient for expressing the interaction between each
endpoint and the intermediary. A separate CPA would express whatever
configuration information has to be known between the two endpoints
(marketplace clients); possibly, this CPA would be only a subset of the CPA
definition and might require redefining some elements/attributes to have
minOccurs="0". I believe, but am less certain, that a normal CPA would
also suffice to interconnect two adjacent intermediaries. For the example
that I gave in the previous posting, I don't believe that it would be
necessary for those CPAs to reference each other. I am, of course, talking
about a use case in which the intermediary is not "hidden".
Regards,
Marty
*************************************************************************************
Martin W. Sachs
IBM T. J. Watson Research Center
P. O. B. 704
Yorktown
Hts, NY 10598
914-784-7287; IBM tie line 863-7287
Notes address: Martin W Sachs/Watson/IBM
Internet address: mwsachs @ us.ibm.com
*************************************************************************************
Arvola Chan <> on 09/25/2001 03:45:25 PM
To:
christopher ferris <>
cc:
,
Subject: Re: Intermediary support in the 1.1 version of the MSG and CPP/A
specs
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
