A switch receives a data frame with a VLAN tag, tut finds that the destination MAC address of the data frame is not queried in its MAC address table which is the processing behavior of the switch for the data frame,

The function of OSPF hello packets is (). (multiple choice)

What is the total length of the interface identifier of the link-local unicast address?

The output information of a router is as follows. Which is correct? (Multiple choice)

PPP support () authentication protocol, and therefore more secure than the HDLC