多项选择题 ThenetworkadministratorwantstoenableanEtherChannelbetweentwoswitchesin"on"mode.Theadministratorconnectsthecablesandenablestheinterfaces，butwhileconfiguringtheEtherChannelinthefirstswitch，aspanning-treeloopwasdetected.Whichtwooftheseprocedurescanavoidthisproblem？（）

问答题 问ipprecedence有几个bit？

单项选择题 Beforeinsertinganewswitchinthenetwork，thenetworkadministratorchecksthattheVTPdomainnameiscorrect，theVTPmodeissettoserver，andrevisionislowerthantheswitchesinthenetwork.Theadministratorthenconfiguresinterfacesandtrunks，erasesexistingVLANs，andconnectstheswitchtothenetwork.Followingthatprocedure，thereisnoconnectivityinthenetwork.Whatisapossiblecauseofthisproblem？（）