In IEEE 802.3 Ethernet,
Utilization U= 100 * (F/R) / (F/R + T*C)
where , U= Percentage of Utilization
R = Transmission Rate
F = Number of bits in a frame
T = Slot Time
C = Number of Contention Intervals = (1-1/N)1-N - 1
N = Number stations
Frame size = 512 *8 = 4096 bits
F/R = 4096 bits/10 Mbps = 410 µsec
it is given , C = {1-(1/N)}(1-N) – 1 = 1.716,
where no of stations, N = 500
Hence Channel utilization, U = (100* 410) / (410+51.2*1.716) = 82%
