We perform a simplified Ethernet traffic simulation in order to clarify the
physical mechanism of the phase transition behavior which has been
experimentally observed in the flow density fluctuation of Internet traffic. In
one phase traffics from nodes connected with an Ethernet cable are mixed, and
in the other phase, the nodes alternately send bursts of packets. The
competition of sending packets among nodes and the binary exponential back-off
algorithm are revealed to play important roles in producing 1/f fluctuations
at the critical point.Comment: 14 pages, 9 figures. To appear physica