Service Modeling Language: Difference between revisions

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'''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]].

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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.

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 ==

SML has two unique properties that make it well-suited for modeling IT resources and services: support for rich constraints and alignment with XML message exchange architectures. SML allows developers to build modeling information for applications, devices and services that can be used during all stages of the application or service life cycle, such as configuration, problem, change and release management. They are also useful for tactical processes such as management of service levels, availability and capacity. The SML specification provides simplicity, integration and compatibility throughout this life cycle for all components of an IT environment.

SML is a language for building a rich set of constructs for creating and constraining models of complex IT services and systems. SML-based models could include information about configuration, deployment, monitoring, policy, health, capacity planning, target operating range, [[service level agreement]]s, and so on.

An SML model is a set of interrelated [[XML]] documents. An SML model 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:

== External Links ==

* [[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.

* [[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

* Rule documents: constrain the structure and content of documents in a model. SML uses [[Schematron]] and [[XPath]] 1.0 for rules, but allows later versions as well.

* [[http://www.microsoft.com/windowsserversystem/dsi/serviceml.mspx Service Modeling Language Specification]] This specification and SML Schema for download is the first draft of a work in progress (Microsoft site)

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

==SML-Based Models==

[[de:Service Modeling Language]]

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>

# 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.

# 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.

# 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.

# 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.

# 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==

{{Reflist}}

== External Links links==

* [http://www.w3.org/XML/SML W3C Service Modeling Language Working Group home page]

* [http://www.w3.org/XML/SML/#public_drafts W3C public working drafts of SML/SML-IF specification]

[[Category:XML markup languages]]