ITUT Languages SDOs Amardeo Sarma CoChairman ITUT Study

ITU-T Languages @ SDOs Amardeo Sarma Co-Chairman, ITU-T Study Group 17

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

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

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

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

What makes the family different? n n n Real-time, distributed communicating systems Formal, allowing verification and validation u Supports transparency and security requirements Many languages with a graphical syntax Commercial tool support u Tool availability required for approval u 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

The ITU-T language family n n n n SDL – Specification and Description Language MSC – Message Sequence Chart e. ODL – 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

Language Usage n n 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: u Improve quality of standards u Reduce time for standards development But: Use requires some investment ITU-T Study Group 17

Our Strategy at ITU-T SG 17 Keep the edge by concentrating on the differentiating factors and focusing on our strengths ITU-T Study Group 17

What about UML? n n n 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

What about XML? n n n ASN. 1 + XCN (XML Control Notation) u as powerful and expressive as XSD (XML Schema Definition) u 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: //asn 1. elibel. tm. fr/links/#xml ITU-T Study Group 17

UML and XML are easy and popular ASN. 1, MSC, SDL and TTCN support secure, hi-quality standards You use the best of two worlds ITU-T Study Group 17

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

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

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

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

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

Tool usage at ITU-T n n n 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 u The ITU-T CD-ROM, also available for you all, has been a step in this direction! ITU-T Study Group 17

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

Summary of possible actions n n n Understand level of quality and need 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 Q 16/11? ITU-T Study Group 17

Plenty of information on the web ITU-T SG 17: http: //www. itu. int/ITU-T/studygroups/com 17/index. html ASN. 1 Consortium: http: //www. asn 1. org SDL Forum Society: http//www. sdl-forum. org Indian SDL and TTCN Forum: http: //www. sdl-ttcnforum. org/