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ITU-T Languages @ SDOs

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ITU-T Languages @ SDOs

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  1. ITU-T Languages @ SDOs Amardeo SarmaCo-Chairman, ITU-T Study Group 17

  2. Goal of standardisations • Create a common understanding for and define • Infrastructure • Products • Services • Protocols • Enable Communication • Enable interoperability and compatibility • Ease the life of providers and users ITU-T Study Group 17

  3. Special Core Competencies at ITU-T • Carrier class standards and specifications • Experts and drivers in Telecommunications • Strong organisational and logistic support by the TSB • Fast standards track • make even better standards faster Quality of standards play a key role ITU-T Study Group 17

  4. Writing standards • Natural languages • Tables • Diagrams, e.g. sequence diagrams • State diagrams • ...... Usually informal – meaning unclear ITU-T Study Group 17

  5. Improve standards clarity • Natural languages and informal aids not enough • Use formalised techniques • Meaning (semantics) of used notation • Allow automatic checking • Machine-readable specifications – automatic implementation • Since the 70s, ITU-T (then CCITT) has developed FDTs – formal description techniques • Today: ITU-T Language Family ITU-T Study Group 17

  6. What makes the family different? • Real-time, distributed communicating systems • Formal, allowing verification and validation • Supports transparency and security requirements • Many languages with a graphical syntax • Commercial tool support • Tool availability required for approval • Tools vendors directly involved in work • Catering for users both in Industry and in Standards bodies (SDOs), e.g. ITU-T SG 11 ITU-T Study Group 17

  7. The ITU-T language family • SDL – Specification and Description Language • MSC – Message Sequence Chart • eODL – extended Object Definition Language • ASN.1 – Abstract Syntax Notation One • TTCN – Tree and Tabular Combined Notation • CHILL – CCITT HIgh-Level Language • URN – User Requirements Notation • Incorporating Time and Performance into the languages ITU-T Study Group 17

  8. Language Usage • Initially, languages were mainly aimed at standards and Recommendations • For the core languages, industrial use has today far outgrown use in standards! • There is considerable potential left for SDOs to: • Improve quality of standards • Reduce time for standards development • But: Use requires some investment ITU-T Study Group 17

  9. Our Strategy at ITU-T SG 17 Keep the edgeby concentrating on thedifferentiating factors and focusing on our strengths ITU-T Study Group 17

  10. What about UML? • UML is generic, SDL/MSC/TTCN are specific • SDL and MSC experts key for UML 2.0 • Tools for joint support available • UML without SDL is like a car without an engine • Co-operation with OMG in progress • If you really want UML, you can use it without losing the benefits of SDL/MSC ITU-T Study Group 17

  11. What about XML? • ASN.1 + XCN (XML Control Notation) • as powerful and expressive asXSD (XML Schema Definition) • less verbose and much more readable. • ASN.1 is a mature schema notation for XML. No schema mapping is needed • ASN.1/XER: efficient binary encodings with XML (+ XSL)display (or transfer if needed) • CXER èASN.1/XER as a canonical variant of XER for secured transactions • XER tools : http://asn1.elibel.tm.fr/links/#xml ITU-T Study Group 17

  12. UML and XMLare easy and popular ASN.1, MSC, SDL and TTCNsupport secure, hi-quality standards You use the best of two worlds ITU-T Study Group 17

  13. What ITU-Languages do for you • Provide a method supported by tools • Free ASN.1 tools • Free Telelogic reader • Allow checking correctness on the fly • Is the behaviour is what you really intended? • Improves the quality of the standard • Interoperability is greatly improved • Once used properly, helps save time! ITU-T Study Group 17

  14. Obstacles to Language Use • Benefit unclear • Check track record • Formality reduces freedom • Freedom only reduced for issues needed for interoperation, use correct dose of formality • Quick and dirty is better • Are you going to spend more time later fixing holes? ITU-T Study Group 17

  15. Obstacles to Language Use • No expertise in group • Specialists should concentrate on their domain – get support for languages • Missing support • ITU TSB should provide this! • Or ask SG17 – we could e.g. provide tutorials in SDL, ASN.1 etc. • In general: Expertise is available ITU-T Study Group 17

  16. Examples of successful use • ASN.1 • Intelligent network • GSM • UMTS (3G cellphones) • Voice over IP • SDL • IN CS-2 / CS-3 • OSPF (IETF) ITU-T Study Group 17

  17. Remaining problems • Viewing different levels of abstraction • Simplify techniques – lost intuitiveness • Bridge the gap to users without specialist knowledge of formal techniques • Enable bottom-up ITU-T Study Group 17

  18. Tool usage at ITU-T • SDT is currently the standard tool at ITU and ETSI • Recommendation authors send SDT files, which are checked by TSB staff • Formal descriptions are considered non-copyrighted • Common Interchange Format CIF is very important (e.g. for those using Cinderella)! • Availability of cheap or free lightweight tool for standards greatly helps promote SDL/MSC • The ITU-T CD-ROM, also available for you all, has been a step in this direction! ITU-T Study Group 17

  19. Professional support is needed! • To further improve standards quality, SG17 reinforced the recommendation that TSB provide • expertise on a regular basis in the ITU-T languages and methodologies concerning the use of the languages • tools, supporting and facilitating the use of ITU-T languages • We really need permanently available experts at ITU-T: • ETSI success story • Demand must come from users ITU-T Study Group 17

  20. Summary of possible actions • Understand level of quality and need for formalised techniques • Make tool support available • Make professional support available • Tools need improvement to cater for users developing standards • Enable constant feedback from users in standards as from industry • Use the crisis – Start a case study with Q16/11? ITU-T Study Group 17

  21. Plenty of information on the web ITU-T SG17:http://www.itu.int/ITU-T/studygroups/com17/index.htmlASN.1 Consortium: http://www.asn1.orgSDL Forum Society: http//www.sdl-forum.orgIndian SDL and TTCN Forum: http://www.sdl-ttcnforum.org/