Service Level Agreement (SLA)
by
Benedikt Liegener
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last modified
Apr 26, 2012 12:14
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filed under:
KnowledgeModel
Definitions
Term: Service Level Agreement |
Domain: Cross-cutting issues | ||||
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Engineering and Design (KM-ED) |
Adaptation and Monitoring (KM-AM) |
Quality Definition, Negotiation and
Assurance (KM-QA) |
Generic (domain independent) |
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D o m a i n : L a y e r s |
Business Process Management (KM-BPM) |
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Service Composition and
Coordination (KM-SC) |
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Service Infrastructure (KM-SI) |
WS-Agreement is an
OGF proposal for a language and protocol to agree on service usage details. The quality parameters targeted for
the service are called Service Level Objectives (SLOs). SLOs should be
negotiated, agreed upon and monitored for any non-fulfillment, called
SLA violation.[WS-Agreement] WSLA is a framework for specifying and monitoring Service Level Agreements (SLA) for Web Services which aims at automatically measuring and monitoring the QoS parameters, checks the agreed-upon service levels, and is to report violations to the authorized parties involved in the SLA management process. It was designed for a Web Services environment but it is applicable as well to inter-domain management scenarios such as business process and service management or the management of networks, systems and applications in general. The WSLA framework consists of an extensible language based on XML Schema and a runtime architecture comprising several SLA monitoring services, which may be outsourced to third parties to ensure a maximum of accuracy.[WSLA] |
SLAs might specify availability requirements, response times for routine and ad hoc queries, and response time for problem resolution (network down, machine failure, etc.).[Koller et al, 2012] | |||
Generic (domain independent) |
An SLA Contract
is a formal negotiated agreement between two parties. It is a contract
that exists between customers and their service provider, or
between service providers. It transcripts the common understanding
about services, priorities, responsibilities, guarantee, etc. with the
main purpose to agree on the level of
service. For example, it may specify the levels of availability, serviceability, performance,
operation or other attributes of the service like billing and even
penalties in the case of violation of the SLA. [SeCSE] Service Level Agreement is a formal written agreement made between two parties: the service provider and the service recipient. The SLA itself defines the basis of understanding between the two parties for delivery of the service itself. The document can be quite complex, and sometimes underpins a formal contract. The contents will vary according to the nature of the service itself, but usually includes a number of core elements, or clauses. Generally, an SLA should contain clauses that define a specified level of service, support options, incentive awards for service levels exceeded and/or penalty provisions for services not provided. Before having such agreements with customers the IT services need to have a good quality of these services, Quality management will try to improve the QoS, whereas the SLAs will try to keep the quality and guarantee the quality to the customer. [Gridipedia] Service-Level Agreement is that part of a service contract where the level of service is formally defined. In practice, the term SLA is sometimes used to refer to the contracted delivery time (of the service) or performance. [PO-JRA-1.2.1] {SYN: SLA, SLA Contract}{ETC: Service Level Agreement Negotiation} |
A contract between a service provider and a service user or customer that specifies the level of service that is expected during the term of the contract.[Koller et al, 2012] |
Competencies
- UniDue: Quality Assurance; http://www.sse.uni-due.de/wms/en/?go=111;
Klaus Pohl, Andreas Metzger, Osama Sammodi, Eric Schmieders
- POLIMI: Web service orchestration and QoS optimization & Negotiation and QoS agreement; http://home.dei.polimi.it/pernici/ws-research.html; Barbara Pernici, Danilo Ardagna, Pierluigi Plebani, Cinzia Cappiello, Marco Comuzzi
- POLIMI: Dependable Evolvable Pervasive SE; http://deepse.dei.polimi.it/; Carlo Ghezzi, Elisabetta Di Nitto, Valentina Mazza, Luciano Baresi, Andrea Mocci, Luca Cavallaro, Daniel Dubois
- Tilburg: Quality Assurance; http://www.tilburguniversity.nl/eriss/research/; Michael Parkin
- USTUTT: Monitoring of Service Composition; http://www.iaas.uni-stuttgart.de/indexE.php; Frank Leymann, Branimir Wetzstein
- FBK: Service Level Agreements; http://soa.fbk.eu/research.php#id12; Marco Pistore, Annapaola Marconi, Michele Trainotti
- SZTAKI: Service Level Agreements in Grids; http://www.lpds.sztaki.hu; Attila Kertesz
- SZTAKI: SLA Management using Semantic techniques; http://dsd.sztaki.hu; Andras
Micsik
- TUW: Runtime Prediction of SLA Violations in Service Compositions; http://www.infosys.tuwien.ac.at; Martin Treiber
External Competencies
- University of Dortmund: SLA Management; http://www-ds.e-technik.uni-dortmund.de/~yahya/; Rahmin Yahyapour
References
- [PO-JRA-1.2.1] Deliverable PO-JRA-1.2.1 "State of the Art Report, Gap Analysis of Knowledge on Principles, Techniques and Methodologies for Monitoring and Adaptation of SBAs"
- [SeCSE] www.secse-project.eu/
- [Gridipedia] http://www.gridipedia.eu/120.html#c3555 used with permission
- The WSLA Framework: Specifying and Monitoring Service Level Agreements for Web Services. Alexander Keller, Heiko Ludwig. Journal of Network and Systems Management, Vol. 11, No. 1, March 2003.
- [CD-JRA-2.3.4]
Decision support for local adaptation
- [Koller et al, 2012] Koller, B., Laria, G., Karaenke, P., Micsik, A., Frutos, H. M., & Gaeta, A. (2012). Enhancing the Grid with Multi-agent and Semantic Capabilities. In N. Preve (Ed.), Computational and Data Grids: Principles, Applications and Design (pp. 314-342).
- [WSLA] IBM Web Service Level Aggreement (WSLA) Project, http://www.research.ibm.com/wsla/.
- [WS-Agreement]
Open Grid Forum, Web Services Agreement
Specification, March 2007