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Contracts, Service Level Agreements and Virtual Enterprises in Composite Services

Contracts, Service Level Agreements and Virtual Enterprises in Composite Services. Carlos Molina-Jimenez ( Carlos.Molina@ncl.ac.uk ) ADAPT Kick-Off Meeting, Madrid, 23-24 th Sep 2002. Useful notation to remember. E: Enterprise VE: Virtual Enterprise SLA: Service Level Agreement

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Contracts, Service Level Agreements and Virtual Enterprises in Composite Services

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  1. Contracts, Service Level Agreements and Virtual Enterprises in Composite Services Carlos Molina-Jimenez (Carlos.Molina@ncl.ac.uk) ADAPT Kick-Off Meeting, Madrid, 23-24th Sep 2002

  2. Useful notation to remember • E: Enterprise • VE: Virtual Enterprise • SLA: Service Level Agreement • R: Right • O: Obligation • Cli: Client • Srv: Server • BS: Basic Service • CS: Composite Service

  3. Outline of the presentation • Motivation for this presentation • What is a virtual enterprise? • What is a contract? • Contracts in virtual enterprises • What is a SLA? • Relationship between SLAs and contracts? • Conclusions • References

  4. E1 CS E2 BS1 BS2 Motivation for this presentation • ADAPT’s objective: • Creation of CS out of BS How is the interaction between E1 and E2 regulated? Contact What QoS do provide each other? SLA Does CS belong to E1 or E2? VE

  5. How is a VE created? Purpose • -Two or more enterprises • Possibly mutual distrust • Business relationships • Provision of resources/ser- • vices to each other: • electronic and mechanical • components. • cars, ships, computers • and other machinery. • IT, marketing and other services. What is a virtual enterprise?

  6. Shared resources Private resources Efficient provision means sharing VE E1 E2 Private resources Shared resources

  7. VE Shared resources E1 Private resources E2 Private resources Virtual enterprise: logical view

  8. How are disputes prevented? A mechanism to regulate interactions between participating parties is needed. A contract

  9. AGREEMENT Rights Rights Alice Bob Obligations Obligations Alice Bob Signatures Manager E1 Manager E2 What is a contract? • A contract between Alice (the manager of E1) and Bob (the manager of E2) is:

  10. Non-computational computational We did not invent contracts • Have been around for ages. • Used in different situations. • However: Our interest focuses on contracts where the provision of services (resources) heavily depends on the use of computer technology. • These contracts have:

  11. Computational part of contracts • We conceive a contract as • A XML-like script file (readable text and executable part) that can be enacted. • Digital signatures, • Cryptography, other computer technology. • Focus on • enactment • monitoring • renegotiation of parts. • Further research • original negotiation • dispute resolution (in court) done remotely and automatically from the original script file.

  12. AGREEMENT Rights Rights Alice Bob Obligations Obligations Alice Bob Signatures Manager E1Manager E2 Relevance of contracts in VEs. • A contract enactment creates a VE. Private resources E2 VE Shared resources enactment Private resources E1

  13. Bob Alice Rights: to request Doc1. Obligations: not to submit requests on weekends Rights: to check that request was submitted on Mon-Thu Obligations: to provide a copy of Doc1 in less than 24 hs. Example of a contract • “Alice has the right to retrieve a copy of doc1 from Bob’s enterprise, provided that her request is not submitted on Fri, Sat or Sun. Bob has the obligation to provide doc1 in less than 24 hs.” • Rights and obligations:

  14. Contract monitoring architecture Bob’s E2 Alice’s E1 contract monitor request (doc1) Cli Srv check Alice’s ROs check Bob’s ROs reply (doc1) Srv request (doc2) Cli check Bob’s ROs check Alice’s ROs reply (doc2) E-Enterprise, ROs- Rights and Obligations, Cli-Client, Srv-Server

  15. Alice AGREEMENT ABOUT Bob SLA={R1,O1,…Rm,Om,} Definition of SLA • Definition of SLA: • agreement about some specific QoS of interest to Alice and Bob. • defined as a set of named clauses about rights and obligations. For ex. R1- Alice has the right to request Doc1. O1- Alice has the obligation not to submit a request on weekends. R2- Bob has the right to check that the request was submitted on Mon-Thu. etc. Can name can change RO- Rights and Obligations

  16. Service level agreements and rights and obligations • Alice and Bob interaction is defined and regulated by their Rights and Obligations (ROs). • ROs can be named and grouped into SLAs: • SLA1={R1,O1,…Rm1,Om1}, SLA2={R1,O1,…Rm2,Om2}, SLA3={R1,O1,…Rm3,Om3}, … … …

  17. AGREEMENT SLA1={R1,O1,…Rm1,Om1}, SLA2={R1,O1,…Rm2,Om2}, SLA3={R1,O1,…Rm3,Om3}, … … … Signatures Manager E1 Manager E2 SLAs and contracts • A SLA is not a contract. • A contract can be defined in terms of named SLAs: Named SLAs and RO can be: referred, edited, changed.

  18. E1 E2 enactment of the contract creates a VE Conclusion Contracts are needed to create Composite Services.

  19. References • Toward an e-contract management architecture for inter-organizational interaction in TAPAS … John Warne, 2002

  20. AGREEMENT E-signatures Manager E1 Manager E2 Ri: Right, Oi: Obligation E1,E2: Enterprises M1: manager of E1, M2: Manager of E2

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