A method for all-to-all message exchange between program tasks including N>1 hierarchy levels ln, n=1 to N, in which a first level l1 includes a plurality of group tasks and each higher level l(n>1) includes at least one group of level l(n−1) groups to which that task belongs in respective hierarchy levels of the network topology; sending a message via the interconnection network to a respective destination task whose hierarchical identifier is determined; and using the hierarchical identifier to send the program task and the network topology, such that the resulting exchange pattern for the all-to-all message exchange exploits a hierarchical distance in the network topology in a desired manner.