CSMA,althoughmoreefficientthanALOHAorslottedALOHA,stillhasoneglaringinefficiency.Ifthemediumisbusy,thestationwillwaitforarandomamountoftime.Whentwoframescollide,themediumremains()forthedurationoftransmissionofbothdamagedframes.Theuseofrandomdelaysreducestheprobabilityof(请作答此空).For()frames,comparedtopropagationtime,theamountofwastedcapacitycanbeconsiderable.Thiswastecanbereducedifastationcontinuestolistentothemediumwhile().Themaximumutilizationdependsonthelengthoftheframeandonthe()time;thelongertheframesortheshorterthepropagationtime，thehighertheutilization.
A.transmission B.collisions C.transportation D.reception正确答案B
