单项选择题 WhichoftheseisavaliddifferentiatedservicesPHB？（）
多项选择题 Whichtwoofthesearedifferencesbetweentrafficpolicingandtrafficshaping？（）
单项选择题 Youaredesigningyournetworktobeabletousetrunks.AspartofthisprocessyouarecomparingtheISLand802.1Qencapsulationoptions.Allofthesestatementsaboutthetwoencapsulationoptionsarecorrectexceptwhichone？（）
