单项选择题
A.Hub
B.Switch
C.Router
D.Bridge
单项选择题 Anetworktechnicianisinstallingaseriesofthreeaccesspointstocovertheentirewingofabuilding.Eachaccesspointhasawiredconnectionand802.11gisbeingusedforthewirelesstransmission.Whichofthefollowingchannelsshouldbeusedfortheaccesspoints？（）
单项选择题 Atechniciannoticesthatwhentryingtopingaworkstationbynetworknametheworkstationdoesnotreplybackoverthenetwork.TheworkstationispartofthedomainandisabletogettotheInternet.Whichofthefollowingisthecauseoftheproblem？（）
单项选择题 Asecondnetworkcardinaserverthatactivatesiftheprimarycardfailsisanexampleofwhichofthefollowingnetworkperformanceoptimization？（）