Re: Ack Message Payload??

[dick@8760.com]

Jim,

> With respect to MS ACKs sent for Reliable Messaging, the end of MS spec
> 0.21d section 7.11 details the values used... If we agree that an ACK is
> also used to convey BP-level information, then I agree we need to talk
> about this in Tokyo...

It is the piggybacked ACK/BP (RPC-like)  scenario I'm interested in discussing,
unfortunately I will not be attending the Tokyo meeting (take good notes,
please).

To help kick this discussion off; I believe an ACK should be allowed to,
optionally, contain a piggybacked business level response (e.g.
request_stock_quote <----> response_stock_price). The ebXML envelope and headers
can support this behavior without modification (I think). The advantages to this
approach:

- The protocol remains constant; send normal message (request) and receive an
acknowledgement, regardless of processing mode (RPC or messaging). This makes
for a simpler state machine.

- Protocol violations are easier to detect because there is only one type of
acknowledgement message (MessageType=Acknowledgement). When two different ack's
are possible "something" (tpa perhaps) has to define proper protocol behavior
(in case 1 expect a Normal message, in case 2 expect an Ack message, each case
has to be defined accordingly) .

- The MessageType=Normal has a single set of semantics (essentially it's used to
initiate an exchange) and is never used for "acknowledgement" purposes.

- Acknowledgements become a bit more "functional", the payload can contain a
piggybacked business level "response", this would benefit RegRep and other
services that may use RPC like behavior
(e.g. request_tpp <------> response_tpp_document in a
MessageType="Acknowledgement").

my .02

Dick Brooks
http://www.8760.com/