CSMA/CD parameters

• Mini slot time: time duration that is at least as big as two propagation delay
• Mini slot is basis for contention resolution
• Backoff algorithm: The first retransmission time involves zero or one minislot
times, the second involves 0,1,2,3 minislot times and each additional slot
retransmission extends the range the range by a factor of 2 until the maximum
range of 1210
• The average number of minislots in a contention period is approximately e=2.71
therefore the fraction
• The average number of minislots in a contention period is approximately e=2.71
therefore the fraction of time that the channel is busy transmitting frames is
L/R = 1
L/R+tprop+2etprop 1+6.44a

Where a=tprop R/L

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