Broadcasting in Trees with Multiple Originators

Broadcasting is the information dissemination process in a communication network whereby all sites of the network become informed of a given message by calls made over lines of the network. We present an algorithm which, given a tree network and a time, determines a smallest set of subtrees covering sites of the network such that broadcast can be completed within the given time in each subtree. Information developed by the algorithm is sufficient to determine a satisfactory originator and calling scheme within each subtree.