The processing nodes of the iPSC/860 are interconnected in a hypercube architecture. In a hypercube of dimension n, each node has n neighbors and the total number of nodes in the hypercube is . For example, the machine at Oak Ridge National Laboratory (ORNL) has RX nodes. The nodes of a hypercube are assigned unique addresses so that the address of any two neighbors differs in only one binary digit. The maximum data transfer rate between adjacent nodes on the hypercube is 20Mbps.