单项选择题
A. interface bandwidth
B. interface delay
C. interface bandwidth and delay
D. hop count
E. bridge priority
多项选择题 LoopguardandUniDirectionalLinkDetectionbothprotectagainstLayer2STPloops.InwhichtwowaysdoesloopguarddifferfromUDLDinloopdetectionandprevention？（）
多项选择题 WhichtwooptionsarecontainedinaVTPsubsetadvertisement？（）
单项选择题 Refer to the exhibit. In the diagram，the switches are running IEEE 802.1w RSPT. On which ports should root guard be enabled in order to facilitate deterministic root bridge election under normal and failure scenarios？（）