ETSI MTS Meeting: 3GPP and SDL

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ETSI MTS Meeting 3GPP and SDL

• Oct-2000

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Telelogic's Position

• Telelogic actively collaborates with the
  standardization bodies
• Contributors can obtain Telelogic UML, SDL and
  TTCN tools through ETSI
• All the Suites are both available on Windows and
  Unix
• A team led by Olle Hydbom is involved in 3G
  standardization work (and GSM)
• Has directly supplied 3G contributors with some
  Tau licenses
• Is providing expertise (for free) in order to
  make specifications processable by tools, e.g.
  Call control, etc.
• There were some regressions with GSM
  specifications reused in the UMTS context

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Current Use of Modeling Techniques for UMTS
Specifications

• Status by June-00
• Total number of specification documents 238
• SDL 32
• ASN.1 12
• MSC 28
• UML Class diagram 3
• TTCN 3
• Sequence charts 51
• State diagrams 22
• Quality of the diagrams
• Not necessarily formal and coherent
• Mainly for informative description
• Not clear if the SDL specifications are normative
  or informative

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Analysis of the Use of UML

• UML is considered as not formal enough to provide
  valuable help in protocol specifications and has
  not been discussed in the RAN2 methodology group
  at all.
• Consequence infrequent use

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Analysis of the Use of SDL/MSC

• SDL is more used in UMTS than in GSM, but not
  enough
• Much of the SDL comes from GSM
• Too few new uses
• An example of new use Radio Link Control layer
  (RLC)
• 80 pages
• Informative
• Time and SDL expertise were missing on the
  industrial contributor's side
• Contributors NTT Cocomo and Telelogic, Nokia as
  reviewers
• Positive results in the use of SDL Errors have
  been found by simulation
• Conclusion Limited dissemination of SDL

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Potential Benefits of Using SDL/MSC

• UMTS is considerably more complex than GSM
• This can lead to poor quality in the protocol
  specifications and be behind the delivery
  schedule
• SDL is needed for
• Better specification
• Unambiguous
• Detection of inconsistencies
• Detection of errors by simulation
• Easier production of conformance test cases
• Production of TTCN test cases by simulating models

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Analysis of the Use of SDL/MSC

• Causes
• Reluctance of some customers to use SDL
• Because they do not use SDL later in their
  development process
• SDL is not sufficiently well-known by 3GPP
  contributors
• And is considered as difficult to understand

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Proposal

• Our feeling is that 3G contributors (telecom
  equipment manufacturers) are ready to use SDL,
  but they are not educated enough
• To have more SDL in UMTS, ETSI should supply
  training classes
• A concrete example STF 160/161 is developing
  conformance test suites in TTCN (MAC, RLC and RRC
  layers)
• They hoped to start from formal SDL
• They cannot use tools today due to lack of formal
  SDL
• Consequence be behind the time schedule