1. Node failure tolerance in wireless sensor networks CS 2310 Seminar Mengsi Lou

2. Node failure example

3. Node failure models Single node failure Multiple nodes failure

4. Topology management techniques Clustering (SIS super component) hierarchical topology cluster-head aggregates and forwards the data Sleep Cycle Management (SIS advanced algorithm) To conserve energy and extend the network lifetime, some of the redundant nodes in a WSN can be turned off Node Discovery Power Control Movement Control

5. Classification of fault-tolerance mechanisms

6. Single node failures Provisioned tolerance schemes (relatively static) Two notable methodologies : The first is to carefully place redundant nodes in a WSN the second is to designate spares for critical nodes in the network Reactive connectivity restoration schemes (relatively dynamic) Recovery with 2-hop network state Recovery without explicit state update Considering secondary performance objectives

7. Provisioned schemes The first way: adding redundant nodes

8. Provisioned schemes The second way: designate spares for critical nodes

9. Reactive schemes Recovery with 2-hop network state

10. Reactive schemes Recovery without explicit state update

11. Reactive schemes Considering secondary performance (least movement)

12. Classification of fault-tolerance mechanisms

13. multi-node failures The big difference from single node failure: resource conflict

14. Tolerating collocated failures through node relocation

16. Recovery through deployment of stationary relays (1)

18. Recovery through deployment of stationary relays (2)

19. Classification of fault-tolerance mechanisms

20. Thank you