Service-level agreement (original) (raw)

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Official commitment between a service provider and a customer

A service-level agreement (SLA) is an agreement, typically a binding contract, between a service provider and a customer that define particular aspects of the service – such as quality of service, availability, responsibilities – as terms of contract.[1] SLAs are commonly used in the technology industry, and often contain specific service-level objectives for defined service level indicators, such as mean time between failures, mean time to repair, mean time to recovery, network throughput, jitter, uptime, first-call resolution, and turnaround time.

Unlike traditional contracts, SLAs often require parties involved to meet regularly to create an open forum for communication, apply rewards and penalties for performance, and leave room for periodic revisitation to make changes.[2] SLAs may be supported by operational-level agreements, or OLAs.

Since the late 1980s SLAs have been used by fixed-line telecom operators.[3] Larger organizations often maintain many SLAs internally, such that two different units in an organization script an SLA with one unit being the customer and another being the service provider. This practice helps to maintain the same quality of service amongst different units in the organization and also across multiple locations of the organization. This internal scripting of SLA also helps to compare the quality of service between an in-house department and an external service provider.[4]

The output received by the customer as a result of the service provided is the main focus of the service level agreement.

Service level agreements are also defined at different levels:

According to Dinesh Verma, a well-defined and typical SLA will contain the following components:[5]

Backbone Internet providers

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It is not uncommon for an internet backbone service provider (or network service provider) to explicitly state its SLA on its website.[6][7][8] The U.S. Telecommunications Act of 1996 does not expressly mandate that companies have SLAs, but it does provide a framework for firms to do so in Sections 251 and 252.[9] Section 252(c)(1) for example ("Duty to Negotiate") requires incumbent local exchange carriers (ILECs) to negotiate in good faith about matters such as resale and access to rights of way.

New emerging technologies such as 5G bring new complexities to the network operators. With more stringent SLAs and customer expectations, problem resolutions must be prioritized based on impacted subscribers.[10]

For fixed networks subscribers, service modeling appears to be one of the most suitable ways to effectively monitor SLA's and ensure they are met.[11]

A web service level agreement (WSLA) is a standard for service level agreement compliance monitoring of web services. It allows authors to specify the performance metrics associated with a web service application, desired performance targets, and actions that should be performed when performance is not met.

WSLA Language Specification, version 1.0[12] was published by IBM in 2001.

The underlying benefit of cloud computing is shared resources, which are supported by the underlying nature of a shared infrastructure environment. Thus, SLAs span across the cloud and are offered by service providers as a service-based agreements rather than a customer-based agreements. Measuring, monitoring and reporting on cloud performance is based on the end UX or their ability to consume resources. The downside of cloud computing relative to SLAs is the difficulty in determining the root cause of service interruptions due to the complex nature of the environment.

As applications are moved from dedicated hardware into the cloud, they need to achieve the same even more demanding levels of service than classical installations. SLAs for cloud services focus on characteristics of the data center and more recently include characteristics of the network (see carrier cloud) to support end-to-end SLAs.[13]

Any SLA management strategy considers two well-differentiated phases: negotiating the contract and monitoring its fulfillment in real-time. Thus, SLA management encompasses the SLA contract definition: the basic schema with the QoS parameters; SLA negotiation; SLA monitoring; SLA violation detection; and SLA enforcement—according to defined policies.[_citation needed_]

The main point is to build a new layer upon the grid, cloud, or SOA middleware able to create a negotiation mechanism between the providers and consumers of services. An example is the EU–funded Framework 7 research project, SLA@SOI,[14] which is researching aspects of multi-level, multi-provider SLAs within service-oriented infrastructure and cloud computing, while another EU-funded project, VISION Cloud,[15] has provided results concerning content-oriented SLAs.

FP7 IRMOS also investigated aspects of translating application-level SLA terms to resource-based attributes to bridge the gap between client-side expectations and cloud-provider resource-management mechanisms.[16][17] A summary of the results of various research projects in the area of SLAs (ranging from specifications to monitoring, management and enforcement) has been provided by the European Commission.[18]

Outsourcing involves the transfer of responsibility from an organization to a supplier. This new arrangement is managed through a contract that may include one or more SLAs. The contract may involve financial penalties and the right to terminate if any of the SLA metrics are consistently missed. The setting, tracking and managing SLAs is an important part of the outsourcing relationship management (ORM) discipline. Specific SLAs are typically negotiated upfront as part of the outsourcing contract and used as one of the primary tools of outsourcing governance.

In software development, specific SLAs can apply to application outsourcing contracts in line with standards in software quality, as well as recommendations provided by neutral organizations like CISQ, which has published numerous papers on the topic (such as Using Software Measurement in SLAs[19]) that are available in to the public.

  1. ^ Kearney, K.T.; Torelli, F. (2011). "The SLA Model". In Wieder, P.; Butler, J.M.; Theilmann, W.; Yahyapour, R. (eds.). Service Level Agreements for Cloud Computing. Springer Science+Business Media, LLC. pp. 43–68. ISBN 9781461416142.
  2. ^ Shacklett, M.E. (12 January 2011). "Five Key Points for Every SLA". Dell. Archived from the original on 22 December 2012. Retrieved 22 June 2016.
  3. ^ Verma, Dinesh C. "Service level agreements on IP networks." Proceedings of the IEEE, Volume 92, Issue 9, September 2004, pages 1382 to 1388. DOI 10.1109/JPROC.2004.832969. Peer-reviewed IEEE survey of SLA practice on telecommunications and IP networks, covering the historical context of SLAs in fixed-line telecom.
  4. ^ Ding, Jianguo (2010). Advances in Network Management. Auerbach Publications. ISBN 978-1-4200-6455-1.
  5. ^ Verma, Dinesh (September 2004). "Service level agreements on IP networks" (PDF). Proceedings of the IEEE. 92 (9): 1382–1388. doi:10.1109/JPROC.2004.832969. S2CID 263896791. Archived from the original (PDF) on January 9, 2005.
  6. ^ "Global IP Network SLA". NTT Communications. Retrieved 22 June 2016.
  7. ^ "Global Latency and Packet Delivery SLA". Verizon. Retrieved 22 June 2016.
  8. ^ "Business Edition - AT&T U-verse Voice and TV - Terms of Service (TOS) and AT&T Broadband - Service Level Agreement (SLA)". AT&T. Retrieved 22 June 2016.
  9. ^ Wikisource:Telecommunications Act of 1996#SEC. 101. ESTABLISHMENT OF PART II OF TITLE II.
  10. ^ "Ready for anything? How 360⁰ customer experience assurance will help to increase RoI". Infovista. Retrieved 12 April 2023.
  11. ^ "Assuring advanced cloudified networks – why an integrated approach to automated assurance and operations is essential". Infovista. Retrieved 12 April 2023.
  12. ^ Ludwig, Heiko; Keller, Alexander; Dan, Asit; King, Richard P.; Franck, Richard (2003-01-01). "Web Service Level Agreement (WSLA) Language Specification" (PDF).
  13. ^ Rueda, J.L.; Gómez, S.G.; Chimento, A.E. (2011). "The Service Aggregator Use Case Scenario". In Wieder, P.; Butler, J.M.; Theilmann, W.; Yahyapour, R. (eds.). Service Level Agreements for Cloud Computing. Springer Science+Business Media, LLC. pp. 329–342. ISBN 9781461416142.
  14. ^ Butler, J.M.; Yahyapour, R.; Theilmann, W. (2011). "Motivation and Overview". In Wieder, P.; Butler, J.M.; Theilmann, W.; Yahyapour, R. (eds.). Service Level Agreements for Cloud Computing. Springer Science+Business Media, LLC. pp. 3–12. ISBN 9781461416142.
  15. ^ Villari, M.; Tusa, F.; Celesti, A.; Puliafito, A. (2012). "How to Federate VISION Cloud through SAML/Shibboleth Authentication". In De Paoli, F.; Pimentel, E.; Zavattaro, G. (eds.). Service-Oriented and Cloud Computing. Springer-Verlag Berlin Heidelberg. pp. 259–274. ISBN 9783642334276.
  16. ^ Boniface, M.; Nasser, B.; Papay, J.; et al. (2010). "Platform-as-a-Service Architecture for Real-Time Quality of Service Management in Clouds" (PDF). 2010 Fifth International Conference on Internet and Web Applications and Services. pp. 155–160. doi:10.1109/ICIW.2010.91. ISBN 978-1-4244-6728-0. S2CID 8631786.
  17. ^ Cuomo, A.; Di Modica, G.; Distefano, S.; et al. (2013). "An SLA-based Broker for Cloud Infrastructures". Journal of Grid Computing. 11 (March 2013): 1–25. doi:10.1007/s10723-012-9241-4. S2CID 10203057.
  18. ^ Kyriazis, D., ed. (June 2013). "Cloud Computing Service Level Agreements - Exploitation of Research Results". European Commission. p. 51. Retrieved 22 June 2016.
  19. ^ Curtis, B.; Herron, D.; Subramanyam, J. (July 2015). "Using Software Measurement in SLAs: Integrating CISQ Size and Structural Quality Measures into Contractual Relationships" (PDF). CISQ. Retrieved 22 June 2016.