Computers as Components, 2nd Edition

8.7 Design Example: Elevator Controller 427

■ The network must determine how to route data. Sensor networks generally

establish a network structure,such as a grid,based upon the relative locations

of the network nodes. Data are then routed based upon these selected

communication paths.

■ When nodes enter or leave the network, the network must update its

configuration and routing.

In order to support these network operations, nodes in the network must be

fairly capable:

■ The node must be able to turn its radio on and off quickly and efficiently. Power

wasted during power-up and power-down is not available for operating the

network.

■ The radios in the nodes ...