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The Language Family @ ITU-T

The Language Family @ ITU-T. Amardeo Sarma Co-Chairman, ITU-T Study Group 17. Contents. Languages at SG17 ITU-T Languages SDL ASN.1 MSC TTCN Helping you make better standards faster. Languages at SG17. Core Competencies at ITU-T. Carrier class standards and specifications

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The Language Family @ ITU-T

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  1. The Language Family @ ITU-T Amardeo SarmaCo-Chairman, ITU-T Study Group 17

  2. Contents • Languages at SG17 • ITU-T Languages • SDL • ASN.1 • MSC • TTCN • Helping you make better standards faster ITU-T Study Group 17

  3. Languages at SG17

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

  5. Mandate of ITU-T Study Group 17 • Responsible for technical languages, the methods for their usage and other issues related to the software aspects of telecommunication systems. • Studies on modelling, specification and description techniques and on other software aspects in line with the requirements of and in co-operation with the relevant other Study Groups (4,11,13,16). • SG17 is Lead Study Group on Languages and Description Techniques within ITU-T • SG 17 Policy: Strong coupling with industrial needs and use ITU-T Study Group 17

  6. The ITU-T language family • SDL - Specification and Description Language • MSC - Message Sequence Chart • ODL - Object Definition Language (adopted from TINA) • ASN.1 - Abstract Syntax Notation One • TTCN Tree and Tabular Combined Notation • CHILL - CCITT HIgh-Level Language ITU-T Study Group 17

  7. The ITU-T language family (new) • DCL - Distribution and Configuration Language • URN - User Requirements Notation • Incorporating Time and Performance into the languages ITU-T Study Group 17

  8. What makes the family different? • Real-time, distributed communicating systems • Formal, allowing verification and validation • 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

  9. Language Usage • Initially, languages were mainly aimed at standards and Recommendations • For the core languages, industrial use has today far outgrown use in standards! • The use at SDOs is below the potential to: • Improve quality of standards • Reduce time • But: Use requires some investment • Fora support ASN.1, SDL, MSC and TTCN ITU-T Study Group 17

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

  11. ITU-T Languages

  12. SDL • Created for Telecommunications • Centred around the specification of behaviour, good for use in protocols • Allows specification of structure and data • Good tool support, including integration with other techniques • Widely used in standards and even more in industry • Moving to other real-time application areas ITU-T Study Group 17

  13. SDL hot issues • Upgrade of methodologyUML-MSC-ASN.1-SDL-TTCN • CIF for SDL-2000 • MSC data mapping to SDL • Time and performance features • SDL as a UML profile (OMG?) • SDL components for sale • Gnu/Visual SDL?? ITU-T Study Group 17

  14. ASN.1 • International standard : ITU-T X.680 to X.683 | ISO/IEC 8824-1 to 4 with a sizeable base of tools that support ASN.1 • Describes data exchange between two communicating applications • Several associated standardized encodings, such as: • efficient (binary) encoding: Packed Encoding Rules (PER) • canonical encoding for digital signatures:Distinguished Encoding Rules (DER) • XML (textual) encoding rules (XER) with tool support • Mature, long record of reliability and interoperability • ASN.1 is a critical part of our daily lives; it's everywhere, but it works so well it's invisible! ITU-T Study Group 17

  15. ASN.1 and the telecom industry • Intelligent network • GSM • UMTS (3G cellphones) • Voice over IP • Interactive television • Videoconference • SET, C-SET (secured electronic transaction:e-commerce, m-commerce) • Computer-supported telecommunications applications • ... ITU-T Study Group 17

  16. ASN.1 in other domains • Intelligent transportation • Radio-frequency identification (RFID) • ATN (Aeronautical Telecommunication Network) • Embedded systems • Financial operations (ASC X.9, ISO TC 68) • Control of manufacturing systems • And a lot of other application domains:see http://asn1.elibel.tm.fr/uses • Fully integrated in the formal languages SDL and TTCN ITU-T Study Group 17

  17. Z.120 MSC • Current Version: MSC 2000 • Previous Version: MSC ’96 • Next Version: MSC 2004 • Standard consists of: • graphical grammar • ASCII grammar • static & dynamic semantics • formal semantics, Annex B • examples ITU-T Study Group 17

  18. MSC • MSC-2000 is a rich language with rigorously defined semantics, unlike UML sequence charts • One of the advantages over competitors • MSC is widely, but informally, used often independently of other notations. • At IETF, MSC is clearly a candidate to formalise signal flows • There is scope for increased tool/language penetration. • Users are often unaware of Z.120 as a standard for sequence diagrams and that MSC has good tool support. ITU-T Study Group 17

  19. MSC Future Features • Message Channels • Presentation Formats • TTCN Graphical presentation format, Z.142 • semantic restrictions, e.g. tracing • Instantiations of Universal Data Interface • SDL interface scheduled 2002, Z.121 • ASN.1 interface? • TTCN-3 interface? • UML alignment • OMG UML v2.0 sequence diagrams ITU-T Study Group 17

  20. TTCN-3 • Testing and Test Control Notation TTCN-3 is used to write detailed test specifications • Applicable to telecom and datacom testing • Application Areas • protocols • services • APIs • software modules etc. ITU-T Study Group 17

  21. A general purpose testing language • Conformance Testing • Interoperability testing • Robustness testing • Performance testing • regression testing • System testing • Integration testing, etc. ITU-T Study Group 17

  22. Text format Tabular Format MSC Format PresentationFormat3 PresentationFormatn TTCN-3: different presentation formats • Core format is a text based language • Core can be viewed as text or in various presentation formats • Tabular format for conformance testing • Message Sequence Chart (MSC)format • Other standardized formats in the future • Proprietary formats TTCN-3 Core Language ITU-T Study Group 17

  23. What about UML? • 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

  24. 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

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

  26. The next years • After UML 2.0, work together towards • Powerful, new versions of SDL and MSC • Strong bridges to ASN.1 and TTCN in addition to UML • Consolidate and strengthen the use of languages in Telecommunications • Expand further into new domains • Focus on penetrating the IETF in the coming years • Support standardisation and education with tools ITU-T Study Group 17

  27. Helping you make better standards faster

  28. What ITU-Languages do for you • Provide a method supported by commercial and free tools • Allow checking of syntactical and logical (semantic) correctness on the fly • Helps you check if the behaviour is what you intended • Improves the quality of the standard • Interoperability is greatly improved • Once used properly, helps save time! ITU-T Study Group 17

  29. 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 • This is not ITU-T‘s differentiator or unique selling point ITU-T Study Group 17

  30. Obstacles to Language Use • No expertise in group • Specialists should concentrate on their domain – get support for languages • No time • Check whether overall time is lost or gained • Missing support • TSB should provide this! • Or ask SG17 – we could e.g. provide tutorials in SDL, ASN.1 etc. ITU-T Study Group 17

  31. 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-coprighted • 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

  32. 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 permanent experts at ITU-T: • ETSI success story • Demand must come from users ITU-T Study Group 17

  33. ITU-T languages can help ITU-T Recommendations maintain or regain competitive advantage

  34. Support from Fora and Consortia • ASN.1 Consortium: http://www.asn1.org • SDL Forum Society: http//www.sdl-forum.org • Indian SDL and TTCN Forum: http://www.sdl-ttcnforum.org/ ITU-T Study Group 17

  35. ASN.1 Consortium • Group of ASN.1 users (people and companies), specifiers and tool-vendors • Share resources and information • Promote ASN.1 (towards newspaper and journals, companies, universities…) • No standardization work • Three forums: • Industry forum • Standardization forum • Academic forum • Website:http://www.asn1.org ITU-T Study Group 17

  36. ASN.1 – short summary • Robust and stable technology that has withstood the test of time, and which continues to improve over time. • Now supports XML in ITU-T X.693 (XML Encoding Rules) • An easier schema for XML than W3C XML Schema (XSD) • Makes it possible to use XML where it currently is impossible due to XML's verbose size • ITU-T X.694 now makes it possible to convert XSD to ASN.1 • A sizeable base of tools that support ASN.1, including PER and XML, now exists • The rapid degree of ASN.1:2002 features implemented by tool vendors is a testament to the strength of the ASN.1 industry. ITU-T Study Group 17

  37. ASN.1 Types & Values Other types & Values2 Other types & Valuesn TTCN-3 and Other Languages • TTCN can be integrated with other 'type and value' systems • Fully harmonized with ASN.1 (1997) • Harmonization possible with other type and value systems (possibly from proprietary languages) TTCN-3 Core Language ITU-T Study Group 17

  38. Test System Architecture Test Data Data Types Test Behaviour Major Elements of TTCN-3 • Built-in and user-defined generic data types (e.g., to define messages, service primitives, information elements, PDUs) • Actual test data transmitted/received during testing • Definition of the components and communication ports that are used to build various testing configurations • Specification of the dynamic test system behaviour TTCN-3 Core ITU-T Study Group 17

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