单项选择题
A.Address Resolution Protocol （ARP）
B.PDU header rewrite
C.NetFlow switching
D.hello packet exchange
单项选择题 Whichofthefollowingcommandscanbeissuedwithoutinterferingwiththeoperationofloopguard？（）
单项选择题 A port in a redundant topology is currently in the blocking state and is not receiving BPDUs. To ensure that this port does not erroneously transition to the forwarding state， which command should be configured to satisfy the requirement？（）
单项选择题 Whichspanning-treecommandwouldcauseaPortFast-enabledinterfacetoloseitsPortFast-operationalstatusanddisableBPDUfilteringifitreceivesBPDUs？（）