  We analyzed the non-Gaussian nature of network traffic using some Internet
traffic data. We found that (1) the non-Gaussian nature degrades network
performance, (2) it is caused by `greedy flows' that exist with non-negligible
probability, and (3) a large majority of `greedy flows' are TCP flows having
relatively small hop counts, which correspond to small round-trip times. We
conclude that in a network hat has greedy flows with non-negligible
probability, a traffic controlling scheme or bandwidth design that considers
non-Gaussian nature is essential.
