Node failure tolerance

in wireless sensor networks

CS 2310 SeminarMengsi Lou

Node failure example

Node failure models

• Single node failure• Multiple nodes failure

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

Classification of fault-tolerance mechanisms

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

Provisioned schemesThe first way: adding redundant nodes

Provisioned schemes The second way: designate spares for critical

nodes

Reactive schemes Recovery with 2-hop network state

Reactive schemes Recovery without explicit state update

Reactive schemes Considering secondary performance (least

movement)

Classification of fault-tolerance mechanisms

multi-node failures

• The big difference from single node failure: resource conflict

Tolerating collocated failures through node relocation

Tolerating collocated failures through node relocation

Recovery through deployment of stationary relays (1)

Recovery through deployment of stationary relays (1)

Recovery through deployment of stationary relays (2)

Classification of fault-tolerance mechanisms

Thank you