Linear-Time Data Dissemination in Dynamic Networks

Broadcasting and convergecasting are pivotal services in distributed systems, in particular, in wireless ad-hoc and sensor networks, which are characterized by timevarying communication graphs. We study the question of whether it is possible to disseminate data available locally at some process to all n processes in sparsely connected synchronous dynamic networks with directed links in linear time. Recently, Charron-Bost, Függer and Nowak proved an upper bound ofO(n log n) rounds for the case where every communication graph is an arbitrary directed rooted tree. We present a new formalism, which not only facilitates a concise proof of this result, but also allows us to prove that O(n) data dissemination is possible when the number of leaves of the rooted trees are bounded by a constant. In the special case of rooted chains, only (n − 1) rounds are needed. Our approach can also be adapted for undirected networks, where only (n− 1)/2 rounds in the case of arbitrary chain graphs are needed.