In this section we present a randomized algorithm for scheduling the
movements of a set of N packets in a leveled network with depth L.
By assumption, the paths taken by the packets are given and have
congestion c. With high probability, the algorithm delivers all of
the packets to their destinations in 
steps. The
algorithm is on-line in the sense that the schedule is
produced as the packets are routed through the network. (Note: The
number of nodes in the network does not appear in the time to deliver
the packets or in the probability of success. There may be more than
N or fewer.)