单项选择题
A.loop guard
B.PortFast
C.root guard
D.BDPU guard
单项选择题 CustomerXhasahub-and-spokeFrameRelaynetwork，withacentralofficeandtwobranchoffices（RemoteAandRemoteB）.EachlocationhasonlyonephysicallinktotheFrameRelaycloudandRemoteBhasarouterthatisnotaCiscorouter.Sincetheinstallation，thereisnoconnectivitybetweenRemoteBandthecentraloffice.Whatisapossiblesolutiontothisissue？（）
问答题 问10.1.1.0/24 10.1.2.0/24可以将这两条路由汇总成最短的掩码是什么？
多项选择题 ThenetworkadministratorwantstoenableanEtherChannelbetweentwoswitchesin"on"mode.Theadministratorconnectsthecablesandenablestheinterfaces，butwhileconfiguringtheEtherChannelinthefirstswitch，aspanning-treeloopwasdetected.Whichtwooftheseprocedurescanavoidthisproblem？（）
