Re: no synch vs asynch indicator in CPP/CPA

[Martin W Sachs <mwsachs@us.ibm.com>]

I may be repeating what I just said in my response to Chris but let me try
it again.

The question is, why would Sync ever be used?  Possibilities:

   1.  For whatever reason, the business process decides that it must
   receive a sync reply to a request, so it specifies sync in one way or
   another and the result is that the other party is forced provide a sync
   receive capability, meaning that it must receive requests with HTTP and
   send the replies synchronously (in the response to the POST). An example
   of this case is where the BP that sends requests is a browser and has no
   async receive capability.

   2. The BP that receives requests has no capability for sending
   asynchronous replies. But this is backwards.  If it is receiving
   requests, it has server-type function and surely is capable of sending
   asynchronous responses.

Notice also that the delivery channel defines receive capabilities.
However for such a delivery channel a sync/async attribute is really
describing response-sending capabilities, not receive capabilities.  I'm
not sure this matters but there may be a comprehensibility issue for the
standard here.

My conclusion is that it is the BP which cares whether the response is
synchronous or asynchronous although the only obvious example I can think
of is where the BP is actually a browser.  I'm not sure whether that makes
it an implementation matter but it's still the BP characteristics that
count.

One CPP-structural problem with putting the sync/async choice inside the BP
is that it is not clear to me how to convey that information to the rest of
the CPP or CPA, which is  a separate document.  Can the value of an
attribute in the BP document be conveyed back to the CPP or CPA and used to
choose the correct delivery channel or is this a case where the CPP writer
has to know that certain messages must be synchronous and set the service
bindings accordingly?

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
*************************************************************************************



Duane Nickull <duane@xmlglobal.com> on 01/23/2001 02:46:41 PM

To:   christopher ferris <chris.ferris@east.sun.com>
cc:   "ebxml-tp@lists.ebxml.org" <ebxml-tp@lists.ebxml.org>
Subject:  Re: no synch vs asynch indicator in CPP/CPA





christopher ferris wrote:

> The distinction as I see it is that the BP should be
> independent of an implementation, but an implementation
> that supports a BP would be engineered so as to provide for
> either response pattern according to its needs.
>
> Comments?
>>>>>>
Chris:

YOu make some very good points and I fully concur that the synch/asynch
details belong in the CP*

The BP should remain agnostic to certain delivery details.

Duane Nickull