I am sorry I missed the telecon. I have been giving this asymmetry/asynchrony topic more thought and discussing it with some WSRF/Web Service experts in the Globus Alliance. I still think that binding-level reliability can extend the utility of the basic "synchronous" Agreement creation patters and that we should repair the "initiator EPR" mess to render the peer-to-peer asynchronous pattern proposal (with the accept/reject operations). Additionally, I am persuaded that as a practical matter, it may be worth rendering the asymmetric (client-server) interface to support asynchronous (post+poll) messaging because of limitations in the binding and tooling world today. However, I am uncomfortable with the standing proposal and how it uses correlation IDs. As was pointed out to me, there is a related distributed systems management problem of deciding how this ID "namespace" is managed and how information is buffered, e.g. for how long. The low-level binding solution that uses Message-ID has some unaddressed quality of service issues pertaining to how long the IDs are remembered in order to enforce idempotence. It also has security issues pertaining to whether one client can deny service to another by anticipating and "polluting" IDs. I think it would be unfortunate if we replicated all of these flaws in the WS-Agreement WSDL interface. The view I share w/ my Globus colleagues is that we should use WSRF resources to model the buffering state and use those resource EPRs as the correlation IDs, since we are already using WSRF. This alternative is what I was hinting at in an earlier message as "another layer of resources". There are really two reasonable variants to doing this, depending on how we wish to think about the lifecycle of Agreement resources. 1) Change the Agreement resource lifecycle to again capture "pre-agreement" and possibly "post-agreement" states. The pre-agreement state can be used to allow a simple low-latency Agreement creation step and then have the "responder agrees to offer" decision made asynchronously. The initiator can poll or subscribe for notifications to learn what decision is made. The post-agreement state would capture the notion Heiko is arguing for that it is possible to "expire" or "cancel" an agreement without destroying the service interface. I mention this only to carry through the modelling approach; the pre and post states are really independent concepts. 2) Introduce separate PreAgreement and PostAgreement resources that have lifetimes linked with the existing Agreement resource. The PreAgreement resource represents the messaging state for determining whether the responder will agree to the offer or not. When he agrees, the initiator can invoke an operation on the PreAgreement to obtain the Agreement resource EPR. Similarly, the PostAgreement resource would represent the Agreement after it is "expired" or "canceled", obviating the need for an Agreement resource that exists after Heiko's agreement termination? I suppose you could mix the two, using a PreAgreement resource and having a post-agreement state on the Agreement resource, but I think that is a bit strange. I will try to start a separate thread about the termination stuff again... Personally, I prefer (1) as I think it sets us up with a better base on which to integrate future negotiation mechanisms. The Agreement provides a generic introspection interface to present different negotiation lifecycles. Optional RPs could provide info on the specific negotiation process, either as extended pre-agreement states or as references to some other service domain where that info can be found. It was also argued by my WSRF colleagues that this would be easier to implement in practice than a flurry of "smaller" resources, although that might depend on implementation technology? karl -- Karl Czajkowski karlcz@univa.com