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