RE: Different Levels of Reliable Messaging

David,

I am glad you mention the case of intermediaries, because I have been thinking for a while about how that affects Reliable Messaging.

In the case of security, what is usually said in order to justify the need to address it at the SOAP headers level, instead of just using HTTPS, is that you need that level if you want to do end-to-end security. Otherwise intermediate nodes would need to have access to security sensitive information related to the message in order to relay information from hop to hop, and those nodes might not be authorized to do that.

But in the case of reliable messaging, it seems that you should be able to use, for example, SOAP over HTTPR on one hop, and SOAP over JMS on the next hop, and still be able to support reliable messaging end-to-end. (The message goes reliably from A to C iff it goes reliably from A to B and from B to C - for example, B waits until it gets the transport-level ack from C before sending its transport-level ack to A). 

In fact, I think this was the rationale when IBM designed HTTPR, so that you could go from Internet to intranet (and vice versa), using SOAP over HTTPR on the Internet, and then switching to SOAP over MQSeries (or other MOM) once inside the intranet. 

Your previous message seems to imply that this approach would not be sufficient for end-to-end reliable messaging. Could you please elaborate?

Thank you,
Ugo

Received on Thursday, 12 December 2002 20:56:06 UTC