[wsrp-wsia] [I#8] Tentative resolution of: Look at work of BTP withregards to 2-phase commit and its viability

[Rich Thompson <richt2@us.ibm.com>]

I looked at the BTP committee specification. It defines a protocol for
business to business transaction.

BTP defines that interactions happen in a 2-phase manner. The first of
these is an exchange of messages that determine the characteristics and
performance of a "Provisional Effect". The second then causes the
finalization (either Confirm or Cancel) of the Effect. In essence the
protocol inherently is a 2-phase commit.

In thinking how this might (or might not) map onto the joint spec, be aware
that BTP is a protocol for multi party collaboration to conduct a business
transaction while WSRP/WSIA is a 2 party system for preparing, delivering
and processing interactions with an entity's presentation.

As such, requiring that all "transactions" (if mapped to performInteraction
invocations) have a 2-phase commit structure seems too heavy weight. This
is especially true since those invocations result from End-User interacting
with the entity's presentation rather than the arbitrary invocations BTP
had to deal with.

Conceptually mapping BTP's first phase onto a performInteraction() causing
a state change and then the second phase to getMarkup() causing this state
change to be visible to the End-User almost works. The difference is that
there is no capability to Cancel the state change and therefore it is not
truly a preliminary change.

The other potential mapping of the BTP protocol is that an entity uses it
to actually perform work as a result of a performInteraction() invocation.
Nothing in our protocol prohibits (or encourages) this as basically it is
in the scope of how a particular entity performs work and therefore
out-of-scope for our protocol.

As a result of this analysis, I propose the following resolution of this
issue:

Proposed Resolution: Closed as not relevant due to the use of the BTP
protocol being out-of scope for the WSRP/WSIA protocol and the conceptual
mapping of the protocols onto each other fails due to the differences in
the nature of the interactions and the number of parties involved.