ebxml-msg — archive

Re: T2 Retry with Delivery Receipt

From: System
To: [email protected]
Date: Sun, 16 Sep 2001 17:35:00 -0000

Some responses below. Regards, Marty ************************************************************************************* Martin W. Sachs IBM T. J. Watson Research Center P. O. B. 704 Yorktown Hts, NY 10598 914-784-7287; IBM tie line 863-7287 Notes address: Martin W Sachs/Watson/IBM Internet address: mwsachs @ us.ibm.com ************************************************************************************* Christopher Ferris <[email protected]> on 09/14/2001 03:00:01 PM To: David Fischer <[email protected]> cc: Martin W Sachs/Watson/IBM@IBMUS, Dan Weinreb <[email protected]>, [email protected] Subject: Re: T2 Retry with Delivery Receipt David, In this case, where the MSH doesn't support ebXML RM protocol, you cannot send a message with OnceAndOnlyOnce semantics. It MUST send back an error "Not Supported". MWS: Which MSH do you refer to here? The first IM or the destination endpoint? Clearly if either the first IM or the destination doesn't support RM but does support ebXML-MS, it must send back "not supported". If the node that receives the message doesn't understand ebXML at all, it can't send anything back and isn't an MSH at all. This may be obvious but that isn't clear from some of the postings. My point is that the RM protocol is hop-to-hop and the end-to-end semantics are achieved by having each hop be reliable (whether using ebXML RM or something else). MWS: Yes, but the ebXML or ebXML-RM protocol terminates at the last point at which there is an ebXML MSH (should be obvious also). Think of it this way: (routing app) | | A[eb] <-> [eb]B B[MQ] <-> [MQ]C In this case, the B intermediary is reliable and supports both ebXML RM *and* MQ series. Whether these are separate instances or the same instance with multiple capabilities is irrelevant. It may be distributed for that matter. The routing app needs to be reliable as well (just as any other app) because it should ONLY mark the message as having been processed if it has successfully processed it. MWS: In this case, the ebXML-MS protocol terminates at the left side of B and B's left side is the From MSH by definition. From an ebXML viewpoint, B and everything to the right of it are part of the system above the B MSH. The B-C link is no more part of the ebXML protocol than is an SMTP intermediate node. We can be more explicit regarding what responsibilities are at an intermediary node here, but IMHO, there really is no difference here between a routing "application" and an endpoint business "application" in that the MSH has a responsibility to ensure that the "application" processes the message. MWS: I agree with this but we must state explicitly at a minimum that intermediate nodes must store and forward reliably. The B node above could all be a single piece of software, operating as a routing intermediary (which would certainly make it more robust), but we have nothing to say on the matter as far as our specification is concerned. MWS: Indeed. We also have nothing to say about C or the link between B and C. I don't think that we need to address the situation where two adjacent nodes don't support the same RM protocol. That would be (IMHO) no different that an SMTP node trying to foist the SMTP protocol on an HTTP server. They speak different protocols and can never interact directly without some manner of gateway. MWS: True. That situation is basically impossible. Cheers, Chris David Fischer wrote: > > Chris, > > What do you mean by unreliable? I will agree there is no unreliable IM but > there can be an IM which does not support ebXML RM (e.g. uses MQSeries instead). > This is the whole point of the reliableMessageMethod parameter. > > David Fischer > Drummond Group. > >