Re: Announce: WS-Callback, WS-MessageData, and WS-Acknowledgement specifications

> Well, reliability goes beyond acknowledgement.

In the final analysis, it doesn't.  It (RM) tries a little harder, but it
relies
on the same simple technique.  And in the end, an audit (end-to-end
state comparison) is the only truth.

>In the HTTP case, I can tell if my request/response failed if I don't
receive a response within the HTTP timeout time. But what if the HTTP
receiver got the message but simply was not able to respond? If the request
is not idempotent (e.g. increase a bank account by $1000), I cannot just
resend the original request without worrying about "once and only once"
semantics.

That's true, but  you could pretend you were the auditor, and cut
to the chase.  It could be argued that a good distributed object design
would follow that principle.  It could even be an architectural principle,
not just a good practice.

>
> So HTTP itself needs something more for reliability, and that's why in the
past things like HTTP-R were defined.

How widely is HTTP-R deployed?  If it's successful, why haven't I heard
about it?  If it's not successful, why would the next generation of the same
saw be?  (What would be different?)

Walden

Received on Friday, 16 May 2003 13:14:36 UTC