Re: FW: Reliable Messaging Summary

Just a couple of parenthetical comments about reliable messaging.

(1) "Reliability" is not a single goal, an objective function that we
are seeking to optimize. It describes a spectrum of
possibilities. If we accept that  there are costs associated with 
different
levels of reliability, we must accept that there may be cases
where application deliberately choose a lower reliability
to satisfy their overall requirements.

(2) The requirement of transport independence (including
the dynamic composition of multiple transports) means that
at the web services architectural level the specification,
description, and negotiation of reliability cannot be
couched in transport-specific or even message-specific
terms. (If my messages are conveyed using a black-box
service that guarantees the required reliability, I
should not have to understand exactly how it achieves
this.)

If we put these together, it seems that a discussion of reliability
at the web services architecture level should involve the
development of an ontology of reliability as well as standard
mechanisms for describing and negotiating various levels
of reliability. These might be expressed in terms of SOAP
and WSDL constructs and negotiation MEPs.

Received on Wednesday, 5 March 2003 09:22:11 UTC