● In multipoint networks , there are tree persistence methods when a station finds a channel busy.in the 1-persistent method,after the station finds the line idle,it sends its frame immediately.this method has the ( ) chance of collision because two or more stations may find the line ( ) and send their frames immediately. In the nonpersistent method , a station that has a frame to send ( ) the line . If the line is idle , it sends immediately If the line is not idle , it waits a ( ) amount of time and then senses the line again.The nonpersistent approach ( ) the chance of collision because it is unlikely that two or more stations will wait the same amount of time and retry to send simultaneously The p-persistent approach combines the advantages of the other two strategies . It reduces the chance of collision and improves efficiency.
(71)A.the lowest
B.the highest
C.possible
D.no
(72)A.idle
B.busy
C.useful
D.unusable
(73)A.overhears
B.hears
C.listens
D.senses
(74)A.random
B.big
C.medium
D.small
(75)A.increases
B.equalizes
C.reduces
D.cancels
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