Detecting cuts in sensor networks

Abstract

We propose a low-overhead scheme for detecting a network partition or cut in a sensor network. Consider a network S of n sensors, modeled as points in a two-dimensional plane. An ε- cut , for any 0 < ε < 1, is a linear separation of ε n nodes in S from a distinguished node, the base station . Our main result is that, by monitoring the status of just O (1/ε) nodes in the network, the base station can detect whenever an ε- cut occurs. Furthermore, this detection comes with a deterministic guarantee that every reported cut has size at least ε n /2. Besides this combinatorial result, we also propose efficient algorithms for finding the O (1/ε) nodes that should act as sentinels , and report on our simulation results, comparing the sentinel algorithm with two natural schemes based on random sampling.