1. Contracts, Service Level Agreements and Virtual Enterprises in Composite Services Carlos Molina-Jimenez ( Carlos.Molina@ncl.ac.uk) Carlos.Molina@ncl.ac.uk ADAPT Kick-Off Meeting, Madrid, 23-24 th 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. Motivation for this presentation ADAPT’s objective: Creation of CS out of BS BS2BS1 E1 E2 CS 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. What is a virtual enterprise? -Two or more enterprises -Possibly mutual distrust -Business relationships How is a VE created? Provision of resources/ser- vices to each other: electronic and mechanical components. cars, ships, computers and other machinery. IT, marketing and other services. Purpose

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

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

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

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

10. 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: computational Non- computational

11. Computational part of contracts We conceive a contract as A XML-like script file (readable text and executable part) that can be enacted. o Digital signatures, o 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. Relevance of contracts in VEs. A contract enactment creates a VE. Obligations Alice Rights Bob Rights Obligations Bob AGREEMENT Signatures Manager E1 Manager E2 Private resources Private resources E1 E2 Shared resources VE enactment

13. 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: 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. Alice Bob

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

15. 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. RO- Rights and Obligations Alice SLA={R 1,O 1,…R m,O m, } AGREEMENT ABOUTBob For ex. R 1 - Alice has the right to request Doc1. O 1 - Alice has the obligation not to submit a request on weekends. R 2 - Bob has the right to check that the request was submitted on Mon-Thu. etc. Can name can change

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: SLA 1 ={R 1,O 1,…R m1,O m1 }, SLA 2 ={R 1,O 1,…R m2,O m2 }, SLA 3 ={R 1,O 1,…R m3,O m3 }, … … …

17. 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. Signatures Manager E1 Manager E2 AGREEMENT SLA 1 ={R 1,O 1,…R m1,O m1 }, SLA 2 ={R 1,O 1,…R m2,O m2 }, SLA 3 ={R 1,O 1,…R m3,O m3 }, … … …

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

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

21. R i : Right, O i : Obligation E-signatures Manager E1 Manager E2 AGREEMENT E1,E2: Enterprises M1: manager of E1, M2: Manager of E2