Among the configuration BPDUs sent by the switch, which bridge D. is unlikely to appear? ()

What kind of packets does the OSPF protocol use to request LSAs that are missing locally? ()

The network shown in the figure below. The host has an ARP cache. Which of the following statements are correct? )(Multiple Choice Questions)

At what layer of the OSI reference model does a router operate? ( )

All four switches run STP, and various parameters adopt default values. If the G0/0/2 port of switch C is blocked and the configuration BPDU cannot be sent through this port, how long will the blocked port in the network enter the forwarding state ()