1. Detecting OAM&P design defects using a feature interaction approach - Internet telephoney service focus Team 9+ 5004692 2273994 3484095 3028498 5007299 3411946 3474249

2. Purpose Introduce Feature Interaction (FI) and OAM&P Provide methods handling FI Provide methods detecing FI in OAM&P

3. Outline Concepts of FI and OAM&P Current Research Motivation Methods handling FI under OAM&p Case Study Conclusions

4. Feature Interaction Defination: Services running at the same time create undesired alters affecting behaviors

5. Feature Interaction Example: Original Call Screening (OCS) allows users create a blacklist to block calls Call Forwarding Unconditional (CFU) allows users to redirect call FI Problems: If user A has OCS with user C and user B has CFU to C when A calls B, FI problem occurs

6. OAM&P Operation Adminstration Maintance Provision

7. OAM&P Functions of OAM&P Operations: Coordinating between other aspects Adminstration: Designing network, processing orders, assigning address, tracking usages and accounting Maintance: Diagnosing and repairing errors Provisioning: Installing equipment, setting paremeters,verfying service, updating and de-installing

8. Current Reserach Motivation Foucs on grey-colour components Few studies on addressing problems TMN frames (FCAPS) standarize OAM&P implentation in PTSN No more interest in OAM&P FI because OAM&P not directly influence end-user's usage of service

9. Methods Handling FI Handling FI Problems Period: Design Time Components 1. Detecting 2. Resolving

10. Detecting & Resolving FI 1. Detecting FI Service operation logic need to be modelled in a suitable formalism Detecting alogrithm should be applied 2. Resolving FI Design need to be reviewed

11. P509 FI Detection Method Period: 1995-1996 Area: European Companies Object: consistent and cost-effective FI solution covering whole service lifecycle Mission:analyzing all solutions and modelling approaches reported by specialized literature so far

12. P509 FI Detection Method Defining four FI detection models 1. Concept-based 2. Goal-based 3. Feature invocation graph ‐ based 4. Pre/post ‐ condition ‐ based NOTE: Only first detection applied to OAM&P features!

13. P509 FI Detection Method Details: 1.Modelling a service as a sequence of manipulations performed on concepts; 2.Manipulation actions could be to read or to modify; 3.Concepts are addresses, call state, charging records, etc; 4.Comparing two service models. Example: An interaction detected service reads a concept that is modified by the other service

14. P509 FI Detection Method Applied to previous example:

15. OAM&P Modelling Feature Relationship Changes made to P509: 1.Features:System concept and entites OAM&P services built on 2. Relationship 2.1 Use:not affect data or processing 2.2 Modify: affect data or processing

16. FI Detection Procedure 1.General Princples: Comparison of couples of ERs 2.Two Types: (1)UM: A uses C, B modifies C (2)MM: A modifies C, B modifies C 3.Check: (1) UM: B's modify alter A's logic? (2)MM: C accept modify? 4.Results: (1)Not undersirable, ignored. (2)Need to review

17. Case Study Internet Telephoney Softswitch Input:136 ERs Algorithm:

18. Case Study Input and Results:

19. FI Flow Chart - UM Interaction

21. FI Flow Chart - MM Interaction

28. Conclusions: Feature Interaction (FI)could be avoided in design time; Implementing FI problem approach: (1)Modelling Feature relationship 1.UM 2.MM (2)Check each one through compairing (3)Reporting results (4)Modifying Design

29. Thank you for Listening!