Reliability Analysis in Net-Centric Computing

1. Reliability Analysis in Net-Centric Computing Supervisor: Prof. Michael Lyu presented by Chong Ka Lung

2. Outline • Introduction • Net-Centric architecture • Net-Centric configuration • Cost/effective study • Reliability study • Future works

3. Introduction

4. What is net-centric computing? • A new paradigm of client/server computing • Applications are resided, managed, supported and 100% executed on a server • A multi-user operating system • Server distributes the presentation of an application's interface to a client device

5. Benefits • Single-point management • Easy maintenance • Physically and technically secure • Predictable ownership costs • Bandwidth-independent performance

6. Problems of Desktop PCs • Fast obsolescence • Difficult administration • Expensive to maintain • Time consuming for installation • Virus attack

7. Solution - Thin client • Replace desktop PC in net-centric environment • A very small size of client operating system • Reduced hardware costs • Reduced maintenance and support costs • Enhanced security

8. Size comparison

9. Net-Centric architecture & configuration

10. Net-Centric architecture • Net-centric server • Platform-independent middleware • supports heterogeneous platform of operating system • Distributed component API, e.g. CORBA • Wire/Wireless connection

12. Net-Centric configuration

13. Cost/effective study

14. Assumptions • Thin client device is used instead of desktop PC • At most 10, 30 and 50 clients are served concurrently • same speed of processor type is used in desktop PC and in server

15. Comparison of number of hardware components (10 clients)

16. Cost comparison

17. Cost comparison (adding memory and upgrading processor)

18. Reliability study

19. What is reliability? • how long a system is continuously operational • Probability that the system remains operational by time t given that it was started in perfect condition at time 0

20. Client Client Client Hub Hub Hub Client Client Client Architecture Server Server LAN Switch Server

21. System failure n identical servers Client network Server network Software failure Hardware failure n clients n servers processor memory n applications harddisk Fault tree Model

22. Parameter listing

23. Assumptions • Components which will fail: • processor, memory, harddisk • 3 software applications in server • network connection on client and on server • Independent behavior of components

24. Assumptions (2) • In net-centric environment, thin client devices are assumed to be fail-free, while server will fail • In traditional client/server environment, clients will fail as well as server

25. Assumptions (3) • System is considered as failure: • processor fails • memory fails • harddisk fails • 2 out of 3 software applications fail • network connection fails

26. Control result

27. Optimistic failure rate

28. Fault tolerant effect

29. Comparison between net-centric and traditional client/server

30. Future works • Modeling on the non-independent behavior of components • Building reusable component using CORBA • Investigating the software fault tolerant technique in net-centric environment

31. Q & A

32. The End