Symbolic applications tend to pass small messages between nodes in a very random way. In fact, many parallel symbolic codes are communication bound in that the communication represents the computation. Thus, good performance for random communication patterns is important to this class of applications. To provide a controlled simulation of this behavior, a program was written with many communication phases. In each phase, each node was given a destination to send a message. The destinations were a random permutation of the nodes. The number of participating nodes, the length of the messages, whether replies were sent, and the number of stages are all input parameters. Replies were always four bytes and when replies were required, processors waited for replies before proceeding to the next stage. A sample of the results is given in Table 2.