Subject: RE: Negotiation problem
Michael, see below my comments regards /stefano » -----Original Message----- » From: Michael Joya [mailto:mike.joya@xmlglobal.com] » Sent: 30 January 2001 03:25 » To: ebxml-poc@lists.ebxml.org » Subject: Negotiation problem » » » I'm having a little bit of trouble visualizing Collaboration Protocol » Agreement negotiation. The following is a depiction of a CPA negotiation » and an impass I have reached while implementing. Please feel free to » correct me on any of this or provide your own personal view. It's a » fuzzy construction of a scenario, but I think the main points are valid. » » I understand that a CPA is made up from N number of CPP documents, In the current version of the CPA specs, a CPA is composed from TWO CPPs. Extensions to multiple CPPs could happen later. » usually two. The schema for the CPA is static, although it can be » templated from another document that lies outside of the ebxml scope, » commonly known as a business process document. So the runtime I do not think that the "business process document" lies outside the scope of ebXML. In my understanding it is an XML Document conforming to the "BP Specification Schema" and, normally, published in the ebXML repository. » transformation we have is: » » cpaDoc := constructCpaUsingMyBPSchema(bpDoc, cpp1Doc, cpp2Doc) » » Ignoring details such as core component alignment, (which itself » carries a heavy implementation load!) our newly formed CPA document » becomes the basis of communications between two parties with a shared » interest in participating in a known, public business process. » » Let's analyze what's required to happen in real life before two » parties engage in that business process. I'll call the two parties » Initiator and Respondant from here on. » » -- » Respondant takes a BP document and her business's CPP and puts them » in a public place. This can be a web site, distribution CD, FTP site, or » even via a public ebXML registry - using the recently inducted bootstrap I do not recall any public discussion on the "inducted bootstrap CPA", but I may have lost it. Could you please point it to me? In addition, I would think that the CPP (which "points" to the BP document) is "normally" published in the RegRep. » CPA. The proprietary BP document allows some kind of parameterization to » take place over the creation of the CPA document. The BP could even be a » textual or UML representation of what message must be sent to who, and » in what order, and so on. What do you mean by "proprietary BP document"? In my understanding the BP document will be available in XML form conforming to the Specification Schema. » » Initiator finds said BP and CPP documents and decides to do business » (discovers the Respondant?). Before an ebXML message is sent off, the » initiator needs to have formed a CPA, and its corresponding CPAId. » Knowning his own CPP, having the Respondant's on hand, and having a » BP document to use as an aide, the Initiator magically puts the pieces » of the puzzle together and forms the CPA. The use of "magically" does not reflect well the concept, I think. Whilst (as Marty Sachs pointed out yesterday) it is not in the scope of the CPA team to define the exact algorithm which defines the composition, the CPA team will work in such a way that it will be practical to derive the logical composition rules for the CPA (not the algorithm) » » The Initiator now has what is required to send off his first message. » But wait! The CPA agreement magically created by the Initiator must also » be exist in the Respondant's possession! Three possibilities exist - » » Either the Initiator submits this CPA to the Respondant's registry via » the bootstrap protocol » OR » The Respondant must calculate the exact same CPA as her potential » client. » OR » The Initiator sends the requested CPA to a human Respondant agent for » manual trust validation. (By phone, etc) » ..... » -- Honestly, I do not think that the CPA team will have the time to work on this issue in the way you address it in the timeframe between now an Vienna. What I personally think is that what will happen will be, at the beginning, a little bit less automated. The Initiator and the Respondant will, logically, build the CPA "together" (I say logically in the sense that even if one of the two actually compiles it, the other one needs to validate it and agree with it); after all the CPA is about an "agreement". I do not think that we are there yet to define the protocol for an automatic agreement/negotiation. Once the CPA is built and agreed (somewhat "manually" or using phone/mail/fax/ad-hoc software), the two parties use the CPA to create the RUNTIME software (perhaps you have heard references to my proposal around a Business Service Interface [BSI]). The runtime software of both parties is configured based on the SAME CPA. As soon as the first party sends the "first choreographed message" (defined in the CPA) to the other, the conversation begines and takes place within the two runtimes. » » The problem is that neither of these modes of operation is terribly » viable. I didn't believe it myself until I tried enumerating them in an » implementation. Let's delve further: » - Option one forebodes authentication. There's no way for the » Respondant to assure herself that the initiator is really Boeing, » Coca-Cola, or XML Global; not having established a CPA in the first » place, she has no frame of reference by which to trust the Initiator. It » looks to me as though this option REQUIRES that third party trust » intervene. If so, why is there no specified model for this? » - Option two would be desirable, but unfortunately ebXML specifications » can't dictate any form of implementation. I think this restriction » borders on silly; but since we're all abiding by the rules, this option » can't be enforced in a specification. Not to mention that the » transformation may be parameterized by use of a proprietary BP document. » » - Option three defeats the purpose of an automatic messaging » & discovery system altogether. However, if we all agree that a human » operator should play a part in the negotiation of an ebXML CPA, I'm sure » that as vendors and implementors, we could make this option come to » life. But should we? » » Have I err'd here? Since most of our POC demonstrations take place in » a vacuum and under "cradled" circumstances, we don't run into » negotiation problems very frequently. Has anyone else had similar » trouble implementing negotiation? » » Any and all feedback welcome. » » » » -- » // Michael Joya » // XML Global Research and Development » // 1818 Cornwall Ave. Suite 9 » // Vancouver, Canada » // 604-717-1100x230 » » » »
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