The Language Family @ ITU-T Amardeo Sarma Co-Chairman, ITU-T Study Group 17

The Language Family @ ITU-T

Amardeo SarmaAmardeo SarmaCo-Chairman, ITU-T Study Group 17Co-Chairman, ITU-T Study Group 17

ITU-T Study Group 17

Contents

Languages at SG17Languages at SG17 ITU-T LanguagesITU-T Languages

SDLSDL ASN.1ASN.1 MSCMSC TTCNTTCN

Helping you make better standards fasterHelping you make better standards faster

Languages at SG17


Core Competencies at ITU-T

Carrier class standards and specificationsCarrier class standards and specifications Quality of standards play a key roleQuality of standards play a key role

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

We need to make even better standards fasterWe need to make even better standards faster


Mandate of ITU-T Study Group 17

Responsible for technical languages, the methods Responsible for technical languages, the methods for their usage and other issues related to the for their usage and other issues related to the software aspects of telecommunication systems.software aspects of telecommunication systems.

Studies on modelling, specification and description Studies on modelling, specification and description techniques and on other software aspects in line techniques and on other software aspects in line with the requirements of and in co-operation with with the requirements of and in co-operation with the relevant other Study Groups (4,11,13,16).the relevant other Study Groups (4,11,13,16).

SG1SG177 is Lead Study Group on Languages and is Lead Study Group on Languages and Description Techniques within ITU-TDescription Techniques within ITU-T

SG 1SG 177 Policy: Strong coupling with industrial needs Policy: Strong coupling with industrial needs and useand use


The ITU-T language family

SDL - Specification and Description SDL - Specification and Description LanguageLanguage

MSC - Message Sequence ChartMSC - Message Sequence Chart ODL - Object Definition Language (adopted ODL - Object Definition Language (adopted

from TINA)from TINA) 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


The ITU-T language family (new)

DCL - Distribution and Configuration DCL - Distribution and Configuration LanguageLanguage

URN - User Requirements NotationURN - User Requirements Notation Incorporating Time and Performance into the Incorporating Time and Performance into the

languageslanguages


What makes the family different?

Real-time, distributed communicating systemsReal-time, distributed communicating systems Formal, allowing verification and validationFormal, allowing verification and validation 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


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!

The use at SDOs is below the potential to:The use at SDOs is below the potential to: Improve quality of standardsImprove quality of standards Reduce timeReduce time

But: Use requires some investmentBut: Use requires some investment Fora support ASN.1, SDL, MSC and TTCNFora support ASN.1, SDL, MSC and TTCN


Our Strategy at ITU-T SG 17

Keep the edgeby concentrating on the

differentiating factors and focusing on our strengths

ITU-T Languages


SDL

Created for TelecommunicationsCreated for Telecommunications Centred around the specification of behaviour, Centred around the specification of behaviour,

good for use in protocolsgood for use in protocols Allows specification of structure and dataAllows specification of structure and data Good tool support, including integration with Good tool support, including integration with

other techniquesother techniques Widely used in standards and even more in Widely used in standards and even more in

industryindustry Moving to other real-time application areasMoving to other real-time application areas


SDL hot issues

Upgrade of methodologyUpgrade of methodologyUML-MSC-ASN.1-SDL-TTCNUML-MSC-ASN.1-SDL-TTCN

CIF for SDL-2000CIF for SDL-2000 MSC data mapping to SDLMSC data mapping to SDL Time and performance featuresTime and performance features SDL as a UML profile (OMG?)SDL as a UML profile (OMG?) SDL components for saleSDL components for sale Gnu/Visual SDL??Gnu/Visual SDL??


ASN.1 International standard : ITU-T X.680 to X.683 | ISO/IEC International standard : ITU-T X.680 to X.683 | ISO/IEC

8824-1 to 4 with a sizeable base of tools that support ASN.18824-1 to 4 with a sizeable base of tools that support ASN.1 Describes data exchange between two communicating Describes data exchange between two communicating

applicationsapplications Several associated standardized encodings, such as:Several associated standardized encodings, such as:

efficient (binary) encoding: Packed Encoding Rules (PER)efficient (binary) encoding: Packed Encoding Rules (PER) canonical encoding for digital signatures:canonical encoding for digital signatures:

Distinguished Encoding Rules (DER)Distinguished Encoding Rules (DER) XML (textual) encoding rules (XER) with tool supportXML (textual) encoding rules (XER) with tool support

Mature, long record of reliability and interoperabilityMature, long record of reliability and interoperability ASN.1 is a critical part of our daily lives; it's everywhere, but ASN.1 is a critical part of our daily lives; it's everywhere, but

it works so well it's invisible!it works so well it's invisible!


ASN.1 and the telecom industry Intelligent networkIntelligent network GSMGSM UMTS (3G cellphones)UMTS (3G cellphones) Voice over IPVoice over IP Interactive televisionInteractive television VideoconferenceVideoconference SET, C-SET (secured electronic transaction:SET, C-SET (secured electronic transaction:

e-commerce, m-commerce)e-commerce, m-commerce) Computer-supported telecommunications applicationsComputer-supported telecommunications applications ......


ASN.1 in other domains

Intelligent transportationIntelligent transportation Radio-frequency identification (RFID)Radio-frequency identification (RFID) ATN (Aeronautical Telecommunication Network)ATN (Aeronautical Telecommunication Network) Embedded systemsEmbedded systems Financial operations (ASC X.9, ISO TC 68)Financial operations (ASC X.9, ISO TC 68) Control of manufacturing systemsControl of manufacturing systems And a lot of other application domains:And a lot of other application domains:

see http://asn1.elibel.tm.fr/usessee http://asn1.elibel.tm.fr/uses Fully integrated in the formal languages SDL and Fully integrated in the formal languages SDL and

TTCNTTCN


MSC

Z.120

Current Version: MSC 2000Previous Version: MSC ’96Next Version: MSC 2004

Standard consists of:• graphical grammar• ASCII grammar• static & dynamic semantics• formal semantics, Annex B• examples


MSC

MSC-2000 is a rich language with rigorously defined MSC-2000 is a rich language with rigorously defined semantics, unlike UML sequence chartssemantics, unlike UML sequence charts One of the advantages over competitorsOne of the advantages over competitors

MSC is widely, but informally, used often independently of MSC is widely, but informally, used often independently of other notations.other notations. At IETF, MSC is clearly a candidate to formalise signal At IETF, MSC is clearly a candidate to formalise signal

flowsflows There is scope for increased tool/language penetration.There is scope for increased tool/language penetration. Users are often unaware of Z.120 as a standard for sequence Users are often unaware of Z.120 as a standard for sequence

diagrams and that MSC has good tool support.diagrams and that MSC has good tool support.


MSC Future Features Message ChannelsMessage Channels Presentation FormatsPresentation Formats

TTCN Graphical presentation format, Z.142TTCN Graphical presentation format, Z.142 semantic restrictions, e.g. tracingsemantic restrictions, e.g. tracing

Instantiations of Universal Data InterfaceInstantiations of Universal Data Interface SDL interface scheduled 2002, Z.121SDL interface scheduled 2002, Z.121 ASN.1 interface?ASN.1 interface? TTCN-3 interface?TTCN-3 interface?

UML alignmentUML alignment OMG UML v2.0 sequence diagramsOMG UML v2.0 sequence diagrams


TTCN-3

Testing and Test Control Notation TTCN-3 is Testing and Test Control Notation TTCN-3 is used to write detailed test specifications used to write detailed test specifications

Applicable to telecom and datacom testingApplicable to telecom and datacom testing Application Areas Application Areas

protocolsprotocols servicesservices APIsAPIs software modules etc.software modules etc.


A general purpose testing language

Conformance TestingConformance Testing Interoperability testingInteroperability testing Robustness testingRobustness testing Performance testingPerformance testing regression testingregression testing System testingSystem testing Integration testing, etc.Integration testing, etc.


TTCN-3: different presentation formats

Core format is a text Core format is a text based languagebased language

Core can be viewed as Core can be viewed as texttext or in various or in various presentation formatspresentation formats

Tabular formatTabular format for for conformance testingconformance testing

Message Sequence Message Sequence Chart (MSC)formatChart (MSC)format

Other standardized Other standardized formats in the futureformats in the future

Proprietary formatsProprietary formats

PresentationFormat3

PresentationFormatn

TTCN-3 Core Language

Text format

MSC Format

Tabular Format


What about UML?

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 UML without SDL is like a car without an

engineengine Co-operation with OMG in progressCo-operation with OMG in progress If you really want UML, you can use it If you really want UML, you can use it

without losing the benefits of SDL/MSCwithout losing the benefits of SDL/MSC


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


SDL and ASN.1support secure, hi-quality standards

UML and XMLare easy and popular

You use the best of two worlds


The next years

After UML 2.0, work together towardsAfter UML 2.0, work together towards Powerful, new versions of SDL and MSCPowerful, new versions of SDL and MSC Strong bridges to ASN.1 and TTCN in addition Strong bridges to ASN.1 and TTCN in addition

to UMLto UML Consolidate and strengthen the use of languages in Consolidate and strengthen the use of languages in

TelecommunicationsTelecommunications Expand further into new domainsExpand further into new domains Focus on penetrating the IETF in the coming yearsFocus on penetrating the IETF in the coming years Support standardisation and education with toolsSupport standardisation and education with tools

Helping you make better standards faster


What ITU-Languages do for you

Provide a method supported by commercial and free Provide a method supported by commercial and free toolstools

Allow checking of syntactical and logical Allow checking of syntactical and logical (semantic) correctness on the fly(semantic) correctness on the fly

Helps you check if the behaviour is what you Helps you check if the behaviour is what you intendedintended

Improves the quality of the standardImproves the quality of the standard Interoperability is greatly improvedInteroperability is greatly improved

Once used properly, helps save time!Once used properly, helps save time!


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

This is not ITU-T‘s differentiator or unique This is not ITU-T‘s differentiator or unique selling pointselling point


Obstacles to Language Use

No expertise in groupNo expertise in group Specialists should concentrate on their domain – Specialists should concentrate on their domain –

get support for languagesget support for languages No timeNo time

Check whether overall time is lost or gainedCheck whether overall time is lost or gained Missing supportMissing support

TSB should provide this!TSB should provide this! Or ask SG17 – we could e.g. provide tutorials in Or ask SG17 – we could e.g. provide tutorials in

SDL, ASN.1 etc.SDL, ASN.1 etc.


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-coprightedFormal descriptions are considered non-coprighted 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!


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-tools, supporting and facilitating the use of ITU-T languagesT languages

We really need permanent experts at ITU-T:We really need permanent experts at ITU-T: ETSI success storyETSI success story Demand must come from usersDemand must come from users

ITU-T languages can help ITU-T Recommendations

maintain or regain competitive advantage


Support from Fora and Consortia

ASN.1 Consortium: http://www.asn1.orgASN.1 Consortium: http://www.asn1.org SDL Forum Society: http//www.sdl-SDL Forum Society: http//www.sdl-

forum.orgforum.org Indian SDL and TTCN Forum: Indian SDL and TTCN Forum:

http://www.sdl-ttcnforum.org/http://www.sdl-ttcnforum.org/


ASN.1 Consortium Group of ASN.1 users (people and companies), specifiers Group of ASN.1 users (people and companies), specifiers

and tool-vendorsand tool-vendors Share resources and informationShare resources and information Promote ASN.1 (towards newspaper and journals, Promote ASN.1 (towards newspaper and journals,

companies, universities…)companies, universities…) No standardization workNo standardization work Three forums:Three forums:

• Industry forumIndustry forum• Standardization forumStandardization forum• Academic forumAcademic forum

Website:Website: http://www.asn1.orghttp://www.asn1.org


ASN.1 – short summary Robust and stable technology that has withstood the test of Robust and stable technology that has withstood the test of

time, and which continues to improve over time.time, and which continues to improve over time. Now supports XML in ITU-T X.693 (XML Encoding Rules)Now supports XML in ITU-T X.693 (XML Encoding Rules) An easier schema for XML than W3C XML Schema (XSD)An easier schema for XML than W3C XML Schema (XSD) Makes it possible to use XML where it currently is impossible Makes it possible to use XML where it currently is impossible

due to XML's verbose sizedue to XML's verbose size ITU-T X.694 now makes it possible to convert XSD to ASN.1ITU-T X.694 now makes it possible to convert XSD to ASN.1 A sizeable base of tools that support ASN.1, including PER A sizeable base of tools that support ASN.1, including PER

and XML, now existsand XML, now exists The rapid degree of ASN.1:2002 features implemented by tool The rapid degree of ASN.1:2002 features implemented by tool

vendors is a testament to the strength of the ASN.1 industry.vendors is a testament to the strength of the ASN.1 industry.


TTCN-3 and Other Languages

TTCN can be TTCN can be integrated with integrated with other 'type and other 'type and value' systemsvalue' systems

Fully harmonized Fully harmonized with ASN.1 (1997)with ASN.1 (1997)

Harmonization Harmonization possible with other possible with other type and value type and value systems (possibly systems (possibly from proprietary from proprietary languages)languages)

TTCN-3 Core Language

Other types & Values2

Other types & Valuesn

ASN.1 Types & Values


Major Elements of TTCN-3

Built-in and user-defined generic Built-in and user-defined generic data types (e.g., to define messages, data types (e.g., to define messages, service primitives, information service primitives, information elements, PDUs)elements, PDUs)

Actual test data transmitted/received Actual test data transmitted/received during testingduring testing

Definition of the components and Definition of the components and communication ports that are used to communication ports that are used to build various testing configurationsbuild various testing configurations

Specification of the dynamic test Specification of the dynamic test system behavioursystem behaviour

Test Behaviour

Test System Architecture

TTCN-3 Core

Test Data

Data Types

Documents

The Language Family @ ITU-T Amardeo Sarma Co-Chairman, ITU-T Study Group 17