单项选择题 Youaredeployingtwocoreswitches，oneineachbuilding，50kmawayfromeachother.Thecross-connectionbetweenthemwillbeaLayer22-gigabitEtherChannelwithan802.1Qtrunk.Youconfigureditcorrectlybutthelinkdoesnotcomeup.Theportisinthe"adminup"state，andthelineprotocolisinthe"down"state.ThefiberlinkisOK.Whatwouldbethemostlikelyreasonforthelinknottocomeup？（）

单项选择题 CustomerXhasahub-and-spokeFrameRelaynetwork，withacentralofficeandtwobranchoffices（RemoteAandRemoteB）.EachlocationhasonlyonephysicallinktotheFrameRelaycloudandRemoteBhasarouterthatisnotaCiscorouter.Sincetheinstallation，thereisnoconnectivitybetweenRemoteBandthecentraloffice.Whatisapossiblesolutiontothisissue？（）

问答题 whatisDSCP？