Approximation algorithms for information dissemination problems

Broadcasting and gossiping are basic tools for high performance programming on parallel and distributed systems. Unfortunately they are known to be NP-hard problems. The paper deals with approximation algorithms far broadcasting and gossiping. The authors consider both round-complexity and step-complexity in the telephone model. After an overview of previously derived approximation algorithms, they present new strategies for broadcasting and gossiping in any networks. Broadcasting strategies are based on the construction of edge-disjoint spanning trees. Gossiping strategies are based on on-line computation of matching a slang with the gossiping process. The approximation algorithms for broadcasting offer almost optimal complexity when the number of messages to be broadcasted is large. They show that the best approximation algorithm for gossiping performs optimally in many cases. They also show experimentally that it performs faster than the best known hand-made algorithms in some particular cases.