contracts, service level agreements and virtual enterprises in composite services carlos...
TRANSCRIPT
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