itu-t languages @ sdos amardeo sarma co-chairman, itu-t study group 17
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ITU-T Languages @ SDOs
Amardeo SarmaAmardeo SarmaCo-Chairman, ITU-T Study Group 17Co-Chairman, ITU-T Study Group 17
ITU-T Study Group 17
Goal of standardisations
Create a common understanding for and defineCreate a common understanding for and define InfrastructureInfrastructure ProductsProducts ServicesServices ProtocolsProtocols
Enable CommunicationEnable Communication Enable interoperability and compatibilityEnable interoperability and compatibility Ease the life of providers and usersEase the life of providers and users
ITU-T Study Group 17
Special Core Competencies at ITU-T
Carrier class standards and specificationsCarrier class standards and specifications Experts and drivers in TelecommunicationsExperts and drivers in Telecommunications Strong organisational and logistic support by the Strong organisational and logistic support by the
TSBTSB Fast standards trackFast standards track
make even better standards fastermake even better standards faster
Quality of standards play a key roleQuality of standards play a key role
ITU-T Study Group 17
Writing standards
Natural languagesNatural languages TablesTables Diagrams, e.g. sequence diagramsDiagrams, e.g. sequence diagrams State diagramsState diagrams ............
Usually infoUsually inforrmal – meaning unclearmal – meaning unclear
ITU-T Study Group 17
Improve standards clarity
Natural languages and informal aids not enoughNatural languages and informal aids not enough Use formalised techniquesUse formalised techniques
Meaning (semantics) of used notationMeaning (semantics) of used notation Allow automatic checkingAllow automatic checking Machine-readable specifications – automatic Machine-readable specifications – automatic
implementationimplementation Since the 70s, ITU-T (then CCITT) has developed Since the 70s, ITU-T (then CCITT) has developed
FDTs – formal description techniquesFDTs – formal description techniques Today: ITU-T Language FamilyToday: ITU-T Language Family
ITU-T Study Group 17
What makes the family different?
Real-time, distributed communicating systemsReal-time, distributed communicating systems Formal, allowing verification and validationFormal, allowing verification and validation
Supports transparency and security requirementsSupports transparency and security requirements Many languages with a graphical syntaxMany languages with a graphical syntax Commercial tool supportCommercial tool support
Tool availability required for approvalTool availability required for approval Tools vendors directly involved in workTools vendors directly involved in work
Catering for users both in Industry and in Standards Catering for users both in Industry and in Standards bodies (SDOs), e.g. ITU-T SG 11bodies (SDOs), e.g. ITU-T SG 11
ITU-T Study Group 17
The ITU-T language family
SDL – Specification and Description LanguageSDL – Specification and Description Language MSC – Message Sequence ChartMSC – Message Sequence Chart eODL – extended Object Definition Language eODL – extended Object Definition Language ASN.1 – Abstract Syntax Notation OneASN.1 – Abstract Syntax Notation One TTCN – Tree and Tabular Combined NotationTTCN – Tree and Tabular Combined Notation CHILL – CCITT HIgh-Level LanguageCHILL – CCITT HIgh-Level Language URN – User Requirements NotationURN – User Requirements Notation Incorporating Time and Performance into the Incorporating Time and Performance into the
languageslanguages
ITU-T Study Group 17
Language Usage
Initially, languages were mainly aimed at standards Initially, languages were mainly aimed at standards and Recommendationsand Recommendations
For the core languages, industrial use has today far For the core languages, industrial use has today far outgrown use in standards!outgrown use in standards!
There is considerable potential left for SDOs to:There is considerable potential left for SDOs to: Improve quality of standardsImprove quality of standards Reduce time for standards developmentReduce time for standards development
But: Use requires some investmentBut: Use requires some investment
ITU-T Study Group 17
Our Strategy at ITU-T SG 17
Keep the edgeKeep the edge
by concentrating on theby concentrating on the
differentiating factors and differentiating factors and
focusing on our strengthsfocusing on our strengths
ITU-T Study Group 17
What about UML?
UML is generic, SDL/MSC/TTCN are specificUML is generic, SDL/MSC/TTCN are specific SDL and MSC experts key for UML 2.0SDL and MSC experts key for UML 2.0 Tools for Tools for jointjoint support available support available UML without SDL is like a car without an engineUML without SDL is like a car without an engine Co-operation with OMG in progressCo-operation with OMG in progress If you really want UML, you can use it without If you really want UML, you can use it without
losing the benefits of SDL/MSClosing the benefits of SDL/MSC
ITU-T Study Group 17
What about XML? ASN.1 + XCN (XML Control Notation)ASN.1 + XCN (XML Control Notation)
as powerful and expressive asas powerful and expressive as XSD (XML Schema XSD (XML Schema Definition)Definition)
less verbose and much more readable.less verbose and much more readable. ASN.1 is a mature schema notation for XML. No ASN.1 is a mature schema notation for XML. No
schema mapping is neededschema mapping is needed AASN.1/XERSN.1/XER:: efficient binary encodings with XML (+ efficient binary encodings with XML (+
XSL)XSL) display (or transfer if needed)display (or transfer if needed) CXER èASN.1/XERCXER èASN.1/XER as as a canonical variant of XER a canonical variant of XER
for secured transactions for secured transactions XER tools XER tools : : http://asn1.elibel.tm.fr/links/#xmlhttp://asn1.elibel.tm.fr/links/#xml
ITU-T Study Group 17
ASN.1, MSC, SDL and TTCNsupport secure, hi-quality standards
UML and XMLare easy and popular
You use the best of two worlds
ITU-T Study Group 17
What ITU-Languages do for you
Provide a method supported by toolsProvide a method supported by tools Free ASN.1 toolsFree ASN.1 tools Free Telelogic reader Free Telelogic reader
Allow checking correctness on the flyAllow checking correctness on the fly Is the behaviour is what you really intended?Is the behaviour is what you really intended?
Improves the quality of the standardImproves the quality of the standard Interoperability is greatly improvedInteroperability is greatly improved
Once used properly, helps Once used properly, helps savesave time! time!
ITU-T Study Group 17
Obstacles to Language Use
Benefit unclearBenefit unclear Check track recordCheck track record
Formality reduces freedomFormality reduces freedom Freedom only reduced for issues needed for Freedom only reduced for issues needed for
interoperation, use correct dose of formalityinteroperation, use correct dose of formality Quick and dirty is betterQuick and dirty is better
Are you going to spend more time later fixing Are you going to spend more time later fixing holes?holes?
ITU-T Study Group 17
Obstacles to Language Use
No expertise in groupNo expertise in group Specialists should concentrate on their Specialists should concentrate on their
domain – get support for languagesdomain – get support for languages Missing supportMissing support
ITU ITU TSB should provide this!TSB should provide this! Or ask SG17 – we could e.g. provide Or ask SG17 – we could e.g. provide
tutorials in SDL, ASN.1 etc.tutorials in SDL, ASN.1 etc. In general: Expertise is availableIn general: Expertise is available
ITU-T Study Group 17
Examples of successful use
ASN.1ASN.1 Intelligent networkIntelligent network GSMGSM UMTS (3G cellphones)UMTS (3G cellphones) Voice over IPVoice over IP
SDLSDL IN CS-2 / CS-3IN CS-2 / CS-3 OSPFOSPF (IETF) (IETF)
ITU-T Study Group 17
Remaining problems
Viewing different levels of abstractionViewing different levels of abstraction Simplify techniques – lost intuitivenessSimplify techniques – lost intuitiveness Bridge the gap to users without specialist Bridge the gap to users without specialist
knowledge of formal techniquesknowledge of formal techniques Enable bottom-upEnable bottom-up
ITU-T Study Group 17
Tool usage at ITU-T
SDT is currently the standard tool at ITU and ETSISDT is currently the standard tool at ITU and ETSI Recommendation authors send SDT files, which are Recommendation authors send SDT files, which are
checked by TSB staffchecked by TSB staff Formal descriptions are considered non-copFormal descriptions are considered non-copyyrightedrighted Common Interchange Format CIF is very important Common Interchange Format CIF is very important
(e.g. for those using Cinderella)!(e.g. for those using Cinderella)! Availability of cheap or free lightweight tool for Availability of cheap or free lightweight tool for
standards greatly helps promote SDL/MSCstandards greatly helps promote SDL/MSC The ITU-T CD-ROM, also available for you all, The ITU-T CD-ROM, also available for you all,
has been a step in this direction!has been a step in this direction!
ITU-T Study Group 17
Professional support is needed! To further improve standards quality, SG17 To further improve standards quality, SG17
reinforced the recommendation that TSB providereinforced the recommendation that TSB provide expertise on a regular basis in the ITU-T expertise on a regular basis in the ITU-T
languages and methodologies concerning the use languages and methodologies concerning the use of the languagesof the languages
tools, supporting and facilitating the use of ITU-T tools, supporting and facilitating the use of ITU-T languageslanguages
We really need permanently available experts at ITU-We really need permanently available experts at ITU-T:T: ETSI success storyETSI success story Demand must come from usersDemand must come from users
ITU-T Study Group 17
Summary of possible actions
Understand level of quality and need for formalised Understand level of quality and need for formalised techniquestechniques
Make tool support availableMake tool support available Make professional support availableMake professional support available Tools need improvement to cater for users Tools need improvement to cater for users
developing standardsdeveloping standards Enable constant feedback from users in standards as Enable constant feedback from users in standards as
from industryfrom industry Use the crisis – Start a case study with Q16/11?Use the crisis – Start a case study with Q16/11?
ITU-T SG17:http://www.itu.int/ITU-T/studygroups/com17/index.html
ASN.1 Consortium: http://www.asn1.orgSDL Forum Society: http//www.sdl-forum.orgIndian SDL and TTCN Forum: http://www.sdl-ttcnforum.org/
Plenty of information on the webPlenty of information on the web