Need for Specification Techniques in NGN Janusz StateSoft.org Copyrights StateSoft Inc., This information is protected by one or more patent or patent pending. Workshop on Use of ITU-T Formal Languages July 19, 2004 StateSoft

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 2 Potential benefits of using MDA/UML in SG13 Applications Services SG13 First objective: Separation of Applications and Services from the Transport SG13 Second objective: ALL-IP Architecture There is a fundamental conflict between the First and Second objective Transport

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 3 Potential benefits of using UML in SG13 Use of UML notations would allow to precisely show the limits of a transport details need at the Application and Services Level There is fundamentally no need for the Application and Services to be aware of the transport level details: IP, ALL-IP, or NO-IP

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 4 Potential benefits of using UML in SG13 Reducing the text-based specifications ambiguity Reducing the time to market SG13/SG16 Network Convergence at the Service and Applications layers UML supports models interchange.

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 5 : Potential benefits of using VeUML in SG13 Separation of Domains and Concerns is a foundation of VeUML and as such makes expressing a separation of Applications and Services from a Transport a natural and an easy goal to achieve.

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 6 Independent Iteration in Logical (PIM) and Physical (PSM) Architectures Potential benefits of using VeUML in SG13

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 7 : The ultimate benefits of using VeUML in SG13 Executable Architectures build on the VeUML Meta-Architecture foundation: The Architectural Specification is executable The interoperability assurance is very high

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 8 Potential benefits of using UML in SG11 Protocols and Signaling Specifications Development

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 9 Protocol Specification Models Qualities Syntactically simplest models for complex protocols Substantial complex protocol maintenance cost reduction Reducing variety in protocol specification notations Maximize the amount of automatic protocol validation (VeUML) Maximizing the amount of automatically generated protocol executable from the specification (VeUML)

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 10 Comparing Specifications Category RFC3261 SIP PARLAY Ambiguity LevelHighLow Need for Cross-ReferencesHighModerate Interoperability PotentialModerateGood Use of AbstractionCorrect and Incorrect Correct Quality of behavior modelsLowHigher

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 11 Comparing Specifications Approaches Category RFC3261 SIP PARLAY Potential for an automatic meta-protocol validation NoneGood Potential for an automatic executable generation NoneGood Call Model potential for innovative services LowHigher Conclusion: UML allows to build semantically more precise signaling specifications than the text based specifications.

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 12 Interface between the meta-protocols SIP-x and the protocols doing the real Media Transmission work (like MPLS) should be specified using UML.

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 13 VeUML extensions: VeSTD, VeXML, VeMSC, VeSDL. * An immediate automatic representation conversion always possible: VeSTD VeMSC VeSDL VeXML Conversion between protocol representation in VeUML

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 14 VeSTD Example – Partial diagram Completed Ack Confirmed Timer_H_Fires | Transport_Error / Inform_TU Terminated Timer_I_Fires Fragment of RFC3261 INVITE server transactions

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 15 VeSDL Example - Partial Diagram Completed Terminated Ack Confirmed Timer_I_Fires Inform_Tu Timer_I_Fires | Transport_Error Fragment of RFC3261 INVITE server transactions

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 16 Completed Ack / ; Confirmed VeXML Example - Partial Listing Fragment of RFC3261 INVITE server transactions

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 17 VeUML Classes Behavior Generation from System Model MSC In VeUML target executable model is synthesize automatically from elementary representations. Other approaches often use elementary representation for high level simulation only. :IpAppCall :IpCall StateB1 StateA2 StateA3 StateA1 StateB3 ActionA2 StateB2 ActionB1 supervise CallRes ActionA1 ActionB2 supervise CallRes Fragment of Parlay Prepaid

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 18 Suggested usage of UML in NGN (SG11) 1. NGN Control architecture (proposed Q.N1) 2. NGN Control requirements (proposed Q.N2) 3. NGN Control protocols (proposed Q.N3)

SG17 Workshop of Use of ITU-T Formal Languages, Geneva, 17-July 2004 StateSoft 19 Grand Conclusion: UML allows to construct semantically more precise specifications than the text based specifications and as such UML should be a foundation of future specification protocol formats in ITU-T.