International Telecommunication Union   ITU
عربي  |  中文  |  Espa˝ol  |  Franšais  |  Русский
 Advanced Search Advanced Search Site Map Contact us Print Version
Home : ITU-T Home : Study Groups : Study Group 17
Question 13/17 – Formal languages and telecommunication software
(Continuation of Q.11, Q.12, Q.13 and Q.15/17)


This Question covers formal languages to define the requirements, architecture, and behavior of telecommunications systems: requirements languages, specification and implementation languages and languages for Open Distributed Processing (ODP). The formal languages for these areas of engineering are widely used in industry and ITU-T and commercial tools support them.

It has become increasingly important to address Unified Modelling Language (UML) in combination with the ITU-T languages. UML 2.0 has adopted some of the elements of the ITU-T Languages and provides a framework to specialize modelling languages to a particular domain through profiling and also to integrate notations. ITU-T languages can be integrated by means of UML profiles. Z.119 provides guidelines for writing such profiles, and Z.109 is such a profile for the Specification and Description Language.

For harmonization, the languages need to be compared with each other. The meta-grammars of the languages differ, which means that a reader of the Recommendations for different languages has to learn different meta-grammars and the UML profiles may also differ. The harmonizing of the grammar used in the languages is thus a further objective of this Question.

Formal languages can also be used for writing high quality Recommendations. Guidelines for doing so are given in Z.450; further advice on the application of the languages can be found in Z.110. The methodology documents are given in Z.100 Supplement 1, which addresses methods and principles used in a particular discipline.

The Recommendations in the Z.10x-series concern the Specification and Description Language. These Recommendations need to be maintained to meet the needs of users in ITU and industry, and to the development of languages elsewhere, such as at the Object Management Group (OMG). Systems have been engineered using the programming language CHILL (Z.200) so this should be retained as is, though CHILL is no longer considered appropriate for further study.

Relevant Requirements languages that fulfil an important role in the early state of analysis to capture user requirements are Message Sequence Chart (Z.120), and the User Requirements Notation (URN) - Language requirements and framework (Z.150). The URN goal-oriented requirements language and use case maps (UCM) are given in Z.151.

A key aspect of telecommunications systems development is the availability of software to support Open Distributed Processing (ODP). Provision of ODP requires standardization of reference models, architectures, functions, interfaces and languages for specifying these (X.900-series).

Recommendations and Supplements under responsibility of this Question as of 1 December 2008: X.901, X.902, X.903, X.904, X.906, X.910, X.911, X.920, X.930, X.931, X.950, X.952, X.960, Z.100, Z.104, Z.105, Z.106, Z.109, Z.110, Z.111, Z.119, Z.120, Z.121, Z.150, Z.151, Z.200, Z.400, Z.450, Z.600, Z.601 and Supplement 1 to the Z-series.


Study items to be considered include, but are not limited to, what new Recommendations, changes to existing Recommendations, or other provisions are required to:

  1. Ensure the releases of the languages are adapted to further contemporary user requirements?
  2. Support the use of the languages in emerging new architectures and frameworks?
  3. Establish a coherent set of languages supporting development from requirements and high-level design to implementation, execution and deployment?
  4. Support of new versions of related languages such as Abstract Syntax Notation One (ASN.1) and Interface Definition Language (IDL)?
  5. Support the computational modelling of a new generation of telecommunications systems?
  6. Allow the use of ISO/IEC 10646 text to aid human understanding in annotations, names and identifiers, and in text handled in the languages?
  7. Define or revise the definitions of new or existing languages, methodologies and frameworks?
  8. Enable an improved use of UML and ITU-T languages, focusing on improving productivity and the ability to ensure quality?
  9. Determine which additional models, architectures, functions, interfaces and languages are necessary to extend and complement the Reference Model ODP (RM-ODP) for the construction of secure, real-time, and dependable open distributed systems?
  10. What support is needed for the formal languages to play a role in the sensing and alerting of events caused by climate change?


Tasks include, but are not limited to:

  1. Maintain a master list of corrections of the current versions of all languages under maintenance.
  2. Maintain the formal basis for Recommendations, thereby placing emphasis on ease of use and easy maintainability, and continue to maintain the formal basis.
  3. Maintenance of Z.10x-series, Z.11x-series, Z.12x-series, Z.15x-series, Z.400, Z.450, Z.600-series and X.900-series Recommendations as and when needed. The direction of the effort should be towards relative stability of the languages but with improved usability.
  4. Contribute to the development of UML 2.0 profiles for: Abstract Syntax Notation One (ASN.1), Message Sequence Chart (MSC), Testing and Test Control Notation (TTCN), User Requirements Notation (URN), and other ITU-T languages.
  5. Identify and if needed adopt other relevant requirements, specification and implementation languages as ITU-T Recommendations taking into account Z.110.
  6. Produce a 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 ITU-T languages.
  7. Revision of RM-ODP Recommendations in collaboration with ISO/IEC JTC 1/SC 7/WG 19.
  8. Consider the use of ISO/IEC 10646 text in all areas of the languages with the possible exception of keywords.


Recommendations: X.68x- and X.69x-series

Questions: ITU-T Qs 12 and 14/17

Study groups: ITU-T study groups that use ITU-T languages, including SGs 2, 11, 13 and 16

Standardization bodies: ISO/IEC JTC 1; ISO/IEC JTC 1/SC 7/WG 19; ETSI; OMG; IETF

Other bodies: SDL Forum Society


Top - Feedback - Contact Us -  Copyright ę ITU 2009 All Rights Reserved
Contact for this page : TSB EDH
Updated : 2009-01-28