单项选择题 WhenplanningforvoicedeploymentswiththeCiscoUnifiedWirelessIPPhone7921GhandsetinamultifloorbuildingwithaWLANthatoperatesatan11MB/sdatarate，howmanydecibelsreferencedto1milliwattofsame-channelseparationarerecommendedbetweenfloors？（）A.13dBmB.19dBmC.25dBmD.31dBm

单项选择题 Howcanmobiledevicesandwirelessnetworksbesecured？（）

单项选择题 AcomputerisconnectedtothenetworkthroughaNIC，whichhasauniqueassignmentthatiscalledtheEthernetMACaddress.WhichlayeroftheOSImodeldoestheMACaddressusetocommunicatewiththenetwork？（）