Contracts, Service Level Agreements and Virtual Enterprises in Composite Services Carlos Molina-Jimenez ( [email protected]) [email protected].

Contracts, Service Level Agreements and Virtual Enterprises in Composite Services

Carlos Molina-Jimenez

([email protected])ADAPT Kick-Off Meeting, Madrid, 23-24th Sep 2002

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

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

Motivation for this presentation ADAPT’s objective: Creation of CS out of BS

BS2BS1

E1E2

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

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

Efficient provision means sharing

Shared

resources

Private

resourcesPrivate

resources

Shared

resources

E1

E2

VE

Virtual enterprise: logical view

Private

resourcesPrivate

resources

E1

E2

Sharedresources

VE

How are disputes prevented?

A mechanism to regulate interactions between participating parties is needed.

A contract

What is a contract?

A contract between Alice (the manager of E1) and Bob (the manager of E2) is:

ObligationsAlice

AliceRights

BobRights

ObligationsBob

AGREEMENT

SignaturesManager E1 Manager E2

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

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.

Relevance of contracts in VEs.

A contract enactment creates a VE.

ObligationsAlice

AliceRights

BobRights

ObligationsBob

AGREEMENT

SignaturesManager E1 Manager E2

Private

resources

Private

resources

E1

E2

Sharedresource

s

VEenactment

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

Contract monitoring architecture

check Alice’s ROs

check Bob’s ROs

check Bob’s ROs

check Alice’s ROs

Alice’s E1 Bob’s E2contract monitor

request (doc1)

reply (doc1)

request (doc2)

reply (doc2)

Cli

Srv

Srv

Cli

E-Enterprise, ROs- Rights and Obligations, Cli-Client, Srv-Server

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={R1,O1,…Rm,Om,}

AGREEMENT ABOUT Bob

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 namecan change

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},

… … …

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.

SignaturesManager E1 Manager E2

AGREEMENT

SLA1={R1,O1,…Rm1,Om1}, SLA2={R1,O1,…Rm2,Om2}, SLA3={R1,O1,…Rm3,Om3},

… … …

ConclusionContracts are needed to create Composite Services.

BS2BS1

E1E2

CS

BS2BS1

E1E2

CS

SignaturesManager E1 Manager E2

AGREEMENT

SLA1={R1,O1,…Rm1,Om1}, SLA2={R1,O1,…Rm2,Om2}, SLA3={R1,O1,…Rm3,Om3},

… … …Signatures

Manager E1 Manager E2

AGREEMENT

SLA1={R1,O1,…Rm1,Om1}, SLA2={R1,O1,…Rm2,Om2}, SLA3={R1,O1,…Rm3,Om3},

… … …

enactment of the contract creates a VE

E1 E2

References

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

Ri: Right, Oi: Obligation

}O...,O,O,O,...,O,{OO M2q

M22

M21

M1p

M12

M11

E-signaturesManager E1 Manager E2

AGREEMENT

}R...,R,R,R,...,R,{RR M2n

M22

M21

M1m

M12

M11

E1,E2: Enterprises

M1: manager of E1, M2: Manager of E2