URNFR to MSC From UCMs to MSC Daniel

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URN-FR to MSC From UCMs to MSC Daniel Amyot Canada damyot@site. uottawa. ca MITEL

URN-FR to MSC From UCMs to MSC Daniel Amyot Canada [email protected] uottawa. ca MITEL Networks

URN-FR to MSC Page 2 Table of Content u Part – – Motivation Requirements

URN-FR to MSC Page 2 Table of Content u Part – – Motivation Requirements for URN Current proposal Use Case Maps (UCM) as URN-FR u Part – – – II: Moving from URN-FR towards MSC Motivation Data Model, Scenarios, and Transformation Example and Prototype u Part © 2000 I: User Requirements Notation (URN) III: Issues, Conclusions and Future Work Strategic Technology MITEL Networks From URN-FR to MSC

URN-FR to MSC Part I: User Requirements Notation (URN) MITEL Networks

URN-FR to MSC Part I: User Requirements Notation (URN) MITEL Networks

URN-FR to MSC Page 4 Motivation for URN Stage 1 Stage 2 Stage 3

URN-FR to MSC Page 4 Motivation for URN Stage 1 Stage 2 Stage 3 Requirements and Service Description Message Sequence Information Protocols and Procedures Informal requirements? Use Cases? URN! MSC SDL © 2000 u u Common design and standardisation approaches already uses scenarios Needs improvement to cope with new realities Strategic Technology MITEL Networks From URN-FR to MSC

Page 5 URN-FR to MSC User Requirements Notation — Initial Requirements u u u

Page 5 URN-FR to MSC User Requirements Notation — Initial Requirements u u u © 2000 Focus on early stages of design, with scenarios Capture user requirements when little design detail is available No messages, components, or component states required Reusability of scenarios and allocation to components Dynamic refinement capabilities Modelling of agent systems, early performance analysis, and early detection of undesirable interactions Strategic Technology MITEL Networks From URN-FR to MSC

URN-FR to MSC Page 6 u u u u u Use Case Maps as

URN-FR to MSC Page 6 u u u u u Use Case Maps as URN-FR Satisfy most of initial Q 12/10 requirements UCM scenario paths illustrate causal relationships among responsibilities Optional integration of behaviour to structure Description of dynamic variation of behavior/structure Facilitate abstract thinking, provide an overview of the system at an appropriate level of detail Allow reasoning about architectural alternatives Convey a lot of information in a compact form Show interactions of scenarios (features) Low learning curve, positive experience so far © 2000 Strategic Technology MITEL Networks From URN-FR to MSC

URN-FR to MSC Page 7 URN-FR Example Causal Path Start Point © 2000 Responsibilities

URN-FR to MSC Page 7 URN-FR Example Causal Path Start Point © 2000 Responsibilities chk vrfy upd req User: A System chk End Point ring User: B vrfy upd req ring Components Strategic Technology MITEL Networks From URN-FR to MSC

URN-FR to MSC Page 8 © 2000 URN-FR Advanced Notation Strategic Technology MITEL Networks

URN-FR to MSC Page 8 © 2000 URN-FR Advanced Notation Strategic Technology MITEL Networks From URN-FR to MSC

URN-FR to MSC Page 9 Plug-ins for Sorig and Sscreen Sorig IN 1 OUT

URN-FR to MSC Page 9 Plug-ins for Sorig and Sscreen Sorig IN 1 OUT 2 © 2000 Default OUT 1 Originating Teen. Line start check-up User: Orig PIN-entered Originating Call Screening (OCS) Strategic Technology fail [not. Active] [PINvalid] [Active] check. PIN get. PIN [not. PINvalid] [Time. Out] deny MITEL Networks success From URN-FR to MSC

URN-FR to MSC Page 10 Plug-ins for Sterm and Sdisplay ring. Treatment start Sterm

URN-FR to MSC Page 10 Plug-ins for Sterm and Sdisplay ring. Treatment start Sterm IN 1 OUT 2 OUT 1 OUT 4 OUT 3 © 2000 [not. Busy] IN 1 OUT 1 [Busy] busy. Treatment fail report. Success OUT 2 ringing. Treatment Terminating Default Call Name Display (CND) Strategic Technology MITEL Networks disp success From URN-FR to MSC

URN-FR to MSC Part II: Moving from URN-FR towards MSC MITEL Networks

URN-FR to MSC Part II: Moving from URN-FR towards MSC MITEL Networks

URN-FR to MSC Page 12 u u u Motivation for Transformation URN-FR is good

URN-FR to MSC Page 12 u u u Motivation for Transformation URN-FR is good for describing multiple scenarios abstractly and for analysing architectural alternatives (Stage 1). MSCs are better for developing and presenting the details of interactions, for describing lengthy sequences of messages in individual scenarios, and for providing access to well-developed methodologies and tools for analysis and synthesis (Stage 2). URN-FR to MSC transformation bridges the gap between Stage 1 descriptions and Stage 2 descriptions. © 2000 Strategic Technology MITEL Networks From URN-FR to MSC

Page 13 URN-FR to MSC Refining URN-FR with Messages User. A Agent: B chk

Page 13 URN-FR to MSC Refining URN-FR with Messages User. A Agent: B chk vrfy upd req © 2000 Agent. B User. B req User: A Agent: A User: A Agent. A User: B chk msg 1 ring vrfy upd ring SN User. A chk Switch req Switch msg 2 msg 3 msg 4 User: B vrfy upd msg 5 ring chk vrfy upd Strategic Technology SN MITEL Networks ring From URN-FR to MSC User. B

URN-FR to MSC Page 14 u u u u u From URN-FR to MSC

URN-FR to MSC Page 14 u u u u u From URN-FR to MSC URN-FR component ® MSC instance URN-FR path crossing from one component to another ® abstract MSC message URN-FR start (or end) point ® abstract MSC message URN-FR pre/post-condition ® MSC condition URN-FR responsibility ® MSC action URN-FR OR-fork or a dynamic stub with multiple plug-ins ® multiple basic MSCs URN-FR AND-fork ® MSC parallel inline box URN-FR loop ® MSC loop box URN-FR timer ® MSC timer © 2000 Strategic Technology MITEL Networks From URN-FR to MSC

URN-FR to MSC Page 15 Approaches to Transformation u Intermediate – – – Extract

URN-FR to MSC Page 15 Approaches to Transformation u Intermediate – – – Extract LOTOS or SDL model from URN-FR Generate MSC from model High quality and realistic MSC, but much effort u Direct – – Formalism transformation Requires less effort, but MSC of lower quality Might be enough for early analysis and refinement u In both cases, URN-FR descriptions need to be supplemented by a path data model © 2000 Strategic Technology MITEL Networks From URN-FR to MSC

URN-FR to MSC Page 16 u u Need for Data Model 64 potential combination

URN-FR to MSC Page 16 u u Need for Data Model 64 potential combination of end-to-end paths Reduced to 4 when conditions are taken into account Similar problem with combinations of plug-ins in dynamic stubs Path data model can help identify specific scenarios © 2000 Strategic Technology MITEL Networks From URN-FR to MSC

URN-FR to MSC Page 17 Scenario Variables and Definitions u Scenario variables are needed

URN-FR to MSC Page 17 Scenario Variables and Definitions u Scenario variables are needed for conditions u Simplest model: global, boolean, unmodifiable variables, with logical operators u Possible extensions: scoping rules, data types, assignments, sub-scenarios u Scenario definition: named end-to-end scenario characterised by initial values assigned to the (boolean) scenario variables u Scenarios can be grouped for convenience © 2000 Strategic Technology MITEL Networks From URN-FR to MSC

URN-FR to MSC Page 18 Example u From – – © 2000 the example

URN-FR to MSC Page 18 Example u From – – © 2000 the example URN-FR specification: Seven scenario variables are required u Potential of 2^7 = 128 scenarios (assuming all choice points are guarded and deterministic) 15 MSC scenarios can be generated: Basic Call: 2 (success or busy) u CND: 1 (display) u OCS: 3 (success, busy, or denied) u Teen. Line: 6 (active, valid PIN, timeout, busy…) u CND-OCS: 1 (success/display) u CND-Teen. Line: 2 u OCS-Teen. Line: 0 (already covered) u CND-OCS-Teen. Line: 0 (already covered) u Strategic Technology MITEL Networks From URN-FR to MSC

Page 19 URN-FR to MSC Example: OCS, Successful Call u u u u ©

Page 19 URN-FR to MSC Example: OCS, Successful Call u u u u © 2000 sub. OCS = T sub. CND = F sub. TL = F Busy = F On. OCSList = F PINvalid = X TLactive = X Start point = req Strategic Technology MITEL Networks From URN-FR to MSC

URN-FR to MSC Page 20 u u u u OCS - CND Interaction sub.

URN-FR to MSC Page 20 u u u u OCS - CND Interaction sub. OCS = T sub. CND = T sub. TL = F Busy = F On. OCSList = F PINvalid = X TLactive = X Start point = req Desirable interaction! © 2000 Strategic Technology MITEL Networks From URN-FR to MSC

URN-FR to MSC Page 21 u u u u © 2000 OCS - Teen.

URN-FR to MSC Page 21 u u u u © 2000 OCS - Teen. Line Interaction sub. OCS = T sub. CND = F sub. TL = T Busy = T On. OCSList = F PINvalid = F TLactive = T Start point = req Undesirable interaction! Teen. Line prevented by OCS. Strategic Technology MITEL Networks From URN-FR to MSC

Page 22 URN-FR to MSC Prototype: UCMNav 2. 0. 0 (alpha) © 2000 Strategic

Page 22 URN-FR to MSC Prototype: UCMNav 2. 0. 0 (alpha) © 2000 Strategic Technology MITEL Networks From URN-FR to MSC

URN-FR to MSC Part III: Issues, Conclusions and Future Work MITEL Networks

URN-FR to MSC Part III: Issues, Conclusions and Future Work MITEL Networks

URN-FR to MSC Page 24 u u u Issues for Transformation Is URN-FR sufficient?

URN-FR to MSC Page 24 u u u Issues for Transformation Is URN-FR sufficient? Need to consider URN-NFR? Precise URN-FR semantics (plug-in new instances)? Advanced constructs (dyn. resp/comp, comp. types)? Need for intermediate model (LOTOS, SDL, …)? Need for message patterns? How much info in URN? Path data model: align with ASN. 1, MSC’ 2000, SDL? Extend data types (enumerations, integers, …)? Operations on scenario variables by responsibilities? Scope definitions for scenario variables? Token variables for concurrent scenarios? Loop detection? Access to timers (timeouts)? Generation of HMSCs? MSC’ 2000? © 2000 Strategic Technology MITEL Networks From URN-FR to MSC

URN-FR to MSC Page 25 © 2000 Why Stop at MSCs? UML sequence diagrams

URN-FR to MSC Page 25 © 2000 Why Stop at MSCs? UML sequence diagrams UML collaboration diagrams HMSC MSC’ 2000 Rich Trace (XML) URN spec (XML) MSC ’ 96 LOTOS test cases Post. Script Strategic Technology Performance models MITEL Networks TTCN-3 test cases From URN-FR to MSC

URN-FR to MSC Page 26 u u u There is much value in a

URN-FR to MSC Page 26 u u u There is much value in a tool-supported URN-FR-to. MSC translation Need for data model and related issues were identified Good experience so far – u u u Method and tool being applied to industrial examples Prototype under development – u Conclusions and Future Work Should we go Open Source to accelerate its development? Should we target a Rich Trace format? What do we do next? What should be part of the URN standard? © 2000 Strategic Technology MITEL Networks From URN-FR to MSC

URN-FR to MSC Page 27 For More Information… http: //www. Use. Case. Maps. org/urn

URN-FR to MSC Page 27 For More Information… http: //www. Use. Case. Maps. org/urn © 2000 http: //www. cs. toronto. edu/km/GRL/ http: //www. cs. toronto. edu/km/OME/ URN Strategic Technology MITEL Networks From URN-FR to MSC