1. International Telecommunication Union © ITU-T Study Group 17 Integrated Application of URN Daniel Amyot University of Ottawa, Canada damyot@site.uottawa.ca ITU-T Workshop on the Integrated Application of Formal Languages Geneva, September 13, 2003

2. © ITU-T Study Group 17 2003 URN o User Requirements Notation Allows engineers to specify or discover requirements for a proposed system or an evolving system, and review such requirements for correctness and completeness Helps bridging the gap between informal and formal concepts, and between requirements models and design models o URN = GRL + UCM Combines goals and scenarios Graphical notations Reusable patterns o Applicable to various domains (e.g. telecom services, distributed or reactive systems), in industry and SDOs

3. © ITU-T Study Group 17 2003 GRL (URN) o Goal-oriented Requirement Language For incomplete, tentative, (non-functional) requirements Capture goals, objectives, contributions, alternatives, and rationales Supports goal analysis and qualitative evaluations

4. © ITU-T Study Group 17 2003 UCM (URN) o Use Case Maps Causal sequences of responsibilities, allocated to components For operational requirements, as scenarios Support validation, performance analysis, and evaluation of architectural alternatives

5. © ITU-T Study Group 17 2003 Integrating GRL and UCM o Traceability between: Goals/tasks and UCMs (or UCM scenario definitions) Tasks and UCM responsibilities Different granularity Requirements management Others… o Underspecification and overspecification Discovery of new goals and scenarios Removal of unnecessary goals and scenarios Examples: Why is a UCM scenario without any link to a GRL goal? Why is a GRL goal without any link to a UCM scenario? o Refinements of alternative solutions From GRL (identification) to UCM (evaluation)

6. © ITU-T Study Group 17 2003 Minimum MobSC Load Minimum Message Exchange Service in SCP Service in MobSC SDF in SCPSDF in SN Determine SDF Location Impact is vendor-specific High Evolveability High Performance High Throughput Maximum Hardware Utilisation Minimum Changes to Infrastructure Low Cost Less need for new hardware Example GRL Model (Wireless Service)

7. © ITU-T Study Group 17 2003 (c) Service and SDF in SCP Three Alternative Solutions

8. © ITU-T Study Group 17 2003 Integrating UCM and MSC o Automated transformation from UCM to MSC Traversal of UCMs based on Scenario Definitions Enables scenario highlight on UCMs Paths visited can be transformed to MSCs Enables the generation of more detailed design scenarios

9. © ITU-T Study Group 17 2003 UCMNav and Scenario Definitions

10. © ITU-T Study Group 17 2003 Two Resulting MSCs

11. © ITU-T Study Group 17 2003 Integrating UCM and SDL o Generating MSC enables the synthesis of SDL specifications Early prototyping and requirements analysis Some results already available Presented at the 11 th SDL Forum, 2003 UCM UCM Exporter MSC SDL MSC2SDL

12. © ITU-T Study Group 17 2003 Integrating UCM and UML o Similar transformations from UCM to: UML sequence diagrams UML activity diagrams o These can be used to further synthesize state diagrams

13. © ITU-T Study Group 17 2003 Integrating UCM and TTCN-3 o UCM scenarios can be used as test goals Structured UCM scenarios converted to test suite Coverage of operational requirements Another transformation: TTCN-3

14. © ITU-T Study Group 17 2003 UCMNav and UCMExporter o UCMNav 2 generates scenarios (in XML) from traversals http://www.UseCaseMaps.org/tools/uvmnav o UCMExporter takes these as input and generates: MSC (Z.120, textual form) UML sequence diagrams (in XMI) TTCN-3 o http://ucmexporter.sourceforge.net/

15. © ITU-T Study Group 17 2003 Integrating UCM and LQN o Quantitative performance analysis with Layered Queuing Networks o Transformation from complete UCM model to an LQN model Supported by UCMNav o Enables: Analytic evaluations (LQNS) Simulations (LQSim) o http://www.LayeredQueuing.org

16. © ITU-T Study Group 17 2003 UCMs and Performance Response Time Requirement From T1 to T2 Name Response time Percentage SecurityE_Accountant Ready Continue CheckBio TaxPayer Access T1 Timestamp T2 Device Characteristics Processors, disks, DSP, external services… Speed factors Rejected Arrival Characteristics Exponential, or Deterministic, or Uniform, or Erlang, or Other Population size Responsibilities Data access modes Device demand parameters Mean CPU load (time) Mean operations on other devices OR Forks Relative weights (probability) Components Allocated responsibilities Processor assignment Can generate Layered Queuing Networks (LQN) automatically!

17. © ITU-T Study Group 17 2003 From Goals to Design, Performance, and Test Artifacts o Initial traceability from GRL goals to UCMs leads (transitively) to traceability between goals and: Design scenarios (MSC, UML SD) Internal behaviour (SDL) Test (TTCN-3) Performance evalutions (LQN)

18. © ITU-T Study Group 17 2003 Still To Be Explored… o Integrated use of URN and eODL object interfaces Deployments ASN.1 Interface/message definitions Other requirements URN cant express everything…

19. © ITU-T Study Group 17 2003 For More Information… o User Requirements Notation URN Focus Group http://www.UseCaseMaps.org/urn/ o Papers UCM Virtual Library http://www.UseCaseMaps.org/pub/