ebxml-msg — archive

[Jacques Durand]

Interesting analysis. There is a fundamental issue in combining "ebMS-intelligent" routing, and the need to establish a fixed reliability path (using RM seq lifecycle messages) prior to all reliable exchanges to take place between two "multi-hop" parties. WS-Reliability appears easier to deal with for 3 reasons: (a) no separate lifecycle messages, (b) there is the option (like in ebMS2) to *not* use sequence numbers, (c) the Ack semantics is on delivery, which could mean "forward" for an intermediary. This makes it easier to chain several reliable path segments. This is something we will have to seriously consider. At this point it looks like Part 2 - like Core part - cannot afford to ignore either reliability spec. Reliable (ordered) sequences are still something desirable, because they allow for high performance and very robust duplicate detection, and loss detection. But they assume the destination is resolved from the start. WS-Reliability makes this a little more flexible (i.e. sender only has to know what messages are for the same destination, vs. knowing the destination). With WS-ReliableMessaging, an approach could be: All routing is based on wsa:To, which identifies the reliable destination (even if the routing path may change). No ebMS-intelligent routing. Chains of reliable segments appear unsafe, opening loopholes during intermediary forward. In all cases, it seems more important than ever to clarify the requirements for multi-hop, and the use cases to be addressed. Jacques