多项选择题
Which of the following components must be elected before the Spanning Tree Protocol can converge in a switched LAN?（）
A. designated ports. B. duplex operating mode. C. fast mode ports. D. root bridge. E. root ports. F. BDPU priority.
单项选择题 What is the subnetwork number of a host with an IP address of 172.16.210.0/22?（）
多项选择题 Which statements describe the routing protocol OSPF?（）
单项选择题 On point-to-point networks, OSPF hello packets are addressed to which address?（）
