Les Lytollis wrote: > I am implementing a .NET B2B web-based ordering system which will get > its data from a Progress DB on AIX fronted by a bespoke SOP system. For > a number of reasons, we want to let the SOP system query the Progress DB > rather than let the web app query it directly, so the web app will make > a request to the SOP system. > > The suppliers of the SOP system are prepared to make some sort of > listener to accept message requests, but what I can't get my head around > is how I get the message to and from the SOP system. Do I need to create > some sort of server or listener on the web app that can accept > responses? Is this a Web Service? A message queue? SOAP? Uhhhhh -- depends. :-) Your web app is the requester, the SOP system is the responder. Will there always be *one* requester and *one* responder? Or maybe one-to-many, many-to-one, or many-to-many? And what is the time requirement on the response? An "immediate" response like a Web server or "sometime later", batch system style? The answers to those will influence whether you use a direct SOAP over HTTP request or an asynchronous message queue. FWIW! -- Hassan Schroeder ----------------------------- hassan at webtuitive.com Webtuitive Design === (+1) 408-938-0567 === http://webtuitive.com dream. code.