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Question P/17 - System Design Languages Framework and Unified Modelling Language
(continuation of Questions 17/17, 21/17, 22/17, and 23/17 studied during 2001-2004 and Question 28/17 studied during 2002-2004)

1. Motivation

This Question is responsible for Recommendations X.689, Z.109, Z.110, Z.129, Z.139, Z.149, Z.159, Z.400, Z.450, Z.600 and Z.100 Supplement 1.

The issues concerning the System Design Languages (ASN.1 - X.680 series; SDL -Z.100 series; MSC - Z.120 series; eODL - Z.130 series; TTCN - Z.140 series; URN - Z.150 series) across all activities are studied in this Question. Other Questions cover individual languages and activities on requirements; design and implementation; testing and validation.

The need for high quality specifications by industry, ITU, and other bodies such as ETSI using ITU-T Recommendations can be met by machine-readable reference specifications and implementations in System Design Languages, cutting development time and reducing cost as shown by experience. Though System Design Languages are already widely used, in some markets other languages and frameworks have established themselves, which has led to tools being developed that offer the joint use with System Design Languages, in particular Unified Modelling Language (UML) of the Object Management Group (OMG). Until now joint uses have been proprietary leading to incompatibility.

Combined use with UML was studied in 1997-2000 within the SDL study leading to Z.109. It has become increasingly important to address UML in combination with all ITU-T languages. Experts from the System Design Languages domains have been participating in OMG with the initial result that UML has evolved to UML2.0, which has incorporated much of the basis of the System Design Languages. One benefit of the UML approach is that UML provides a framework to integrate notations (such as the System Design Languages) by profiling individual notations and a consensus of the SG 17 Language Co-ordination Project is to use the UML framework to harmonize languages.

Work of a TSAG Correspondence Group with SG10 input resulted (9/1998) in TSAG approval of Guidelines on Quality Aspects of Protocol Related Recommendations as Supplement 1 to the ITU-T A-series Recommendations. These Guidelines embrace specification of protocol-related standards using System Design Languages, and subsequently (08/1999) the Global Standards Collaboration Group approved Resolution 4, applicable to all SGs developing protocol-related Recommendations.

The Guidelines can now be found in Z.450 and further advice on application language can be found in Z.110. To enable better support of fast development of high quality specifications, the following issues have been identified: Promotion of the languages; Further advice on use to ease the writing high quality specifications including use with UML; Support for the use in standards development; Support for SGs on methodologies; Support of libraries (such as that established for ASN.1); Mapping specifications to and from interface descriptions. Use is enhanced by a methodology where a methodology is an organized and coherent set of methods and principles used in a particular discipline and method is the combination of a notation with instructions, rules and guidelines for its use. The existing methodology documents such as Z.100 Supplement 1 need to be enhanced.

The System Design Languages lack some expressive power or support only limited features for describing hard timing constraints for functional verification, performance analysis or implementation. Each language has its own semantics for time, and several means of notations for performance analysis. To enable the languages to be used together, more precise notions of related concepts like atomicity or execution delays are required, and the semantics need to be harmonized.

The primary focus of the Question is integration through UML. To enable such integration, the System Design Languages need to be formulated as UML profiles.

For harmonization, the languages need to be compared with each other. However, the meta-grammars of the System Design Languages differ. This means that a reader of the Recommendations for different System Design Languages may have to learn to read two different meta-grammars to understand both Recommendations and the UML profiles may also differ. The harmonizing of the grammar used in System Design Languages is thus a further objective of this Question.

2. Question

What new Recommendations, Supplements or other provisions are required in order to enable an improved use of UML and ITU-T System Design Languages, thereby especially focusing on improving productivity and the ability to ensure quality ?

3. Tasks

a) Maintain a master list of changes to the current version of all Recommendations under maintenance.

b) Primary responsibility for revision of Recommendation Z.109 - revised as a profile of UML.

c) Primary responsibility for proposed Recommendation X.689 on UML profile for ASN.1.

d) Primary responsibility for proposed Recommendation Z.129 on UML profile for MSC.

e) Primary responsibility for proposed Recommendation Z.139 on UML profile for eODL.

f) Primary responsibility for proposed Recommendation Z.149 on UML profile for TTCN.

g) Primary responsibility for proposed Recommendation Z.159 on UML profile for URN.

h) Supplement to the Z-series Recommendations provisionally entitled "Methodology on the use of description techniques" to replace Z.100 Supplement 1 (10/96) and include a tutorial on the use of UML with System Design Languages.

i) Co-ordination of modelling used for time and performance in ITU-T languages.

j) Co-ordination of meta-grammars for System Design Language Recommendations and consider a Recommendation or other provisions for these meta-grammars.

k) Overview the Language Co-ordination project.

l) Responsibility and revision as and when needed of the following or their replacements or extensions: Z.110, Z.400, Z.450, Z.600.

m) Consider a quality checklist and criteria to help assess Recommendations against Z.450, Quality Aspects of Protocol Related Recommendations and other possible ways to encourage:
  • Study Groups to apply these guidelines;
  • ITU-T member companies to use tools in the review of draft Recommendations;
  • Training in the use of System Design Languages, associated methods and tools;
  • ITU-T to improve System Design Language related technical and editing user support including liaison and collaborate with all relevant Study Groups.

NOTE: in the above "Primary responsibility" is assigned to this Question, but in practice much of the work may be done within the Question responsible for the specific System Design Language.

4. Relationships

Recommendations: X.68x, X.69x, Z.10x, Z.12x, Z.13x, Z.14x, Z.15x, Z.5xx

Questions: M/17, N/17, O/17 and Q/17

Study Groups: Study Groups using UML or System Design Languages, especially ITU-T SGs 4, 11, and 13

Standardization bodies: ETSI (TC MTS); OMG; IETF

Other bodies SDL Forum Society


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