1. In a peer-to-peer real time network in which network state information and data processing is delegated to user nodes, a non-transitory machine-readable medium that contains broadcast control protocol instructions for optimizing packet transfer between a first node and a plurality of related nodes which when executed by a processor cause the processor to perform operations, comprising: assigning to each related node a relevance level i being selected from k relevance levels, indicating the relevance of that related node to the first node; associating with each relevance level i a number of nodes n i , an update message size m i and an update frequency α i ; and determining from an available upstream bandwidth U of the first node a number of levels c i in a broadcast tree of the first node by reference to U=Σ i=1 k ci·sqrt(ni)·mi·α, wherein 0<c i <sqrt(n i ).