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'''Service Modeling Language''' ('''SML''') and '''Service Modeling Language Interchange Format''' ('''SML-IF''') are a pair of [[XML]]-based specifications created by leading [[information technology]] companies that define a set of [[XML]] instance document extensions for expressing links between elements, a set of [[XML Schema (W3C)|XML Schema]] extensions for constraining those links, and a way to associate [[Schematron]] rules with global element declarations, global complex type definitions, and/or model documents. The SML<ref>[http://www.w3.org/TR/sml/ Latest draft of the SML specification]</ref> [[specification]] defines model concepts, and the SML-IF<ref>[http://www.w3.org/TR/sml-if/ Latest draft of the SML-IF specification]</ref> [[specification]] describes a packaging format for exchanging SML-based models.

SML and SML-IF were standardized in a [[W3C]] working group chartered to produce W3C Recommendations for the Service Modeling Language by refining the “Service Modeling Language” (SML) Member Submission,<ref>[http://www.w3.org/Submission/2007/01/ “Service Modeling Language” (SML) Member Submission]</ref> addressing implementation experience and feedback on the specifications. The submission was from an industry group consisting of representatives from BEA Systems, BMC, CA, Cisco, Dell, EMC, HP, IBM, Intel, Microsoft, and Sun Microsystems. They were published as [[W3C Recommendation]]s on May 12, 2009.<ref>[http://www.w3.org/2009/04/sml-pressrelease.html.en SML and SML-IF Recommendation Press Release]</ref> In the market and in applying by vendors,{{whom|date=February 2024}} SML is seen as a successor/replacement for earlier developed standards like [[DCML (markup language)|DCML]] and Microsoft's (in hindsight) proprietary System Definition Model or SDM. See <ref>http://download.microsoft.com/documents/uk/msdn/architecture/infrastructure/infrastructure_and_business_priorities.ppt Powerpoint relating SDM and DCML</ref> for a historically helpful relation between SDM and DCML, and <ref>http://www.hp.com/hpinfo/newsroom/press/2006/060731b.html?jumpid=reg_R1002_USEN Joint press release about SML</ref> for the joint pressrelease announcing SML. In the Microsoft section of it the sequel role to SDM is mentioned.

'''Service Modeling Language''' '''(SML)''' is an [[XML]]-based specification by leading [[information technology]] companies that defines a consistent way to express how computer networks, applications, servers and other IT resources are described or modeled so businesses can more easily manage the services that are built on these resources.

This enables a hierarchy of IT resource models to be created from reusable building blocks rather than requiring custom descriptions of every service, thus reducing costs and system complexity for customers.

SML is currently proposed jointly by [[BEA Systems]], [[BMC Software]], [[Cisco Systems]], [[Dell]], [[EMC Corporation]], [[Hewlett Packard|HP]], [[IBM]], [[Intel]], [[Microsoft]] and [[Sun Microsystems]].

SML addresses a growing industry need as a result of the numerous methods of representing the same IT resource. Besides being inefficient, the use of different formats leads to two problems. First, because the tools and management applications use different formats, they don’t speak the same language. Therefore the information must be translated, which can lead to the loss or misinterpretation of technical details. Second, the use of different formats may require IT architects to use written descriptions or sketches to convey information about resources. Such descriptions must then be translated into a form that tools and management applications can consume, which is a manual, error-prone process.

== Fast Formal Facts about SML ==

TheSML '''Serviceis Modelinga Languagelanguage (SML)'''for providesbuilding a rich set of constructs for creating and constraining models of complex IT services and systems. TheseSML-based models typicallycould include information about configuration, deployment, monitoring, policy, health, capacity planning, target operating range, [[service level agreement]]s, and so on. Models provide value in several important ways.

AAn SML model in SML is realized as a set of interrelated [[XML]] documents. TheAn [[XML]]SML documentsmodel could contain information about the parts of an IT service, as well as the constraints that each part must satisfy for the IT service to function properly. Constraints are captured in two ways:

The '''Service Modeling Language (SML)''' provides a rich set of constructs for creating models of complex IT services and systems. These models typically include information about configuration, deployment, monitoring, policy, health, capacity planning, target operating range, [[service level agreement]]s, and so on. Models provide value in several important ways.

:'''1.''' Models focus on capturing all invariant aspects of a service/system that must be maintained for the service/system to be functional. They capture as much detail as is necessary, and no more.

:'''2.''' Models are units of communication and collaboration between designers, implementers, operators, and users; and can easily be shared, tracked, and revision controlled. This is important because complex services are often built and maintained by a variety of people playing different roles.

:'''3.''' Models drive [[modularity]], [[Re-use]], and [[standardization]]. Most real-world complex services and systems are composed of sufficiently complex parts. [[Re-use]] and [[standardization]] of services/systems and their parts is a key factor in reducing overall production and operation cost and in increasing reliability.

:'''4.''' Models represent a powerful mechanism for validating changes before applying the changes to a service/system. Also, when changes happen in a running service/system, they can be validated against the intended state described in the model. The actual service/system and its model together enable a self-healing service/system – the ultimate objective. Models of a service/system must necessarily stay decoupled from the live service/system to create the control loop.

:'''5.''' Models enable increased automation of management tasks. Automation facilities exposed by the majority of IT services/systems today could be driven by software – not people – for reliable initial realization of a service/system as well as for ongoing lifecycle management.

* [[XML Schema (W3C)|XML Schema]] documents: constrain the structure and content of the XML instance documents in a model. SML uses [[XML Schema (W3C)|XML Schema]] 1.0, but allows later versions as well. SML also defines a set of extensions to [[XML Schema (W3C)|XML Schema]] to constrain references, and identity constraints (key, unique, ...) that apply to sets of documents.

A model in SML is realized as a set of interrelated [[XML]] documents. The [[XML]] documents contain information about the parts of an IT service, as well as the constraints that each part must satisfy for the IT service to function properly. Constraints are captured in two ways:

:'''2.* Rules'''Rule – are [[Boolean expression]]s thatdocuments: constrain the structure and content of documents in a model. SML uses a profile of [[Schematron]] and [[XPath]] 1.0 for rules, but allows later versions as well.

Once a model is defined, one of the important operations on the model is to establish its validity. This involves checking whether all data in a model satisfiesdocuments satisfy the [[XML Schema (W3C)|schemasXML Schema]] and rulesrule declared.document constraints.

==SML-Based Models==

:'''1. Schemas''' – these are constraints on the structure and content of the documents in a model. SML uses a profile of [[XML Schema]] 1.0 as the schema language. SML also defines a set of extensions to [[XML Schema]] to support inter-document references.

Models provide value in several important ways:<ref>[http://www.cml-project.org/2.html Common Model Library - link no longer resolves] {{webarchive|url=https://web.archive.org/web/20080622143643/http://www.cml-project.org/2.html |date=2008-06-22 }}</ref>

:'''2. Rules''' – are [[Boolean expression]]s that constrain the structure and content of documents in a model. SML uses a profile of [[Schematron]] and [[XPath]] 1.0 for rules.

Once a model is defined, one of the important operations on the model is to establish its validity. This involves checking whether all data in a model satisfies the [[XML Schema|schemas]] and rules declared.

:'''1.'''# Models focus on capturing all invariant aspects of a service/system that must be maintained for the service/system to be functional. They capture as much detail as is necessary, and no more.

The SML [[specification]] focuses primarily on defining the profile of [[XML Schema]] and [[Schematron]] used by SML, as well as the process of model validation.

:'''2.'''# Models are units of communication and collaboration between designers, implementers, operators, and users; and can easily be shared, tracked, and revision controlled. This is important because complex services are often built and maintained by a variety of people playing different roles.

:'''3.'''# Models drive [[modularity]], [[Re-use]], and [[standardization]]. Most real-world complex services and systems are composed of sufficiently complex parts. [[Re-use]] and [[standardization]] of services/systems and their parts is a key factor in reducing overall production and operation cost and in increasing reliability.

:'''4.'''# Models represent a powerful mechanism for validating changes before applying the changes to a service/system. Also, when changes happen in a running service/system, they can be validated against the intended state described in the model. The actual service/system and its model together enable a self-healing service/system – the ultimate objective. Models of a service/system must necessarily stay decoupled from the live service/system to create the control loop.

:'''5.'''# Models enable increased automation of management tasks. Automation facilities exposed by the majority of IT services/systems today could be driven by software – not people – for reliable initial realization of a service/system as well as for ongoing lifecycle management.

==References==

== External links ==

{{Reflist}}

== External links ==

* [http://www.serviceml.org/ serviceml.org] Service Modeling Language Work Group main site

* [http://www.servicemlw3.org/XML/SML-200607.pdf W3C Service Modeling Language Specification]Working SpecificationGroup drafthome for downloadpage]

* [http://schemaswww.servicemlw3.org/smlXML/2006SML/07#public_drafts ServiceW3C Modelingpublic Languageworking Schema]drafts of SML/SML-IF Schema specification]

* [http://basman.wordpress.com/2006/08/01/technology-leaders-release-new-specification-to-simplify-it-management/ Service Modeling Language (SML): New Specification to Simplify IT Management] The announcement of the planned standard in the wording of the official joint press text of the initiators and original quotes of their respective managers in charge

[[Category:XML markup languages]]

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