Which of the following IEEE 802.11 standards supports the 2.4 GHz frequency band only?

STA. The only way to discover the wireless network is the Beacom frame sent by the AP. ()

As shown in the figure, the network administrator creates VLAN2 on SWA and SWB. The ports connecting the hosts on the two switches are configured as Access ports. They are assigned to VLAN2. G0/0/1 of SWA and G0/0/2 of SWB are configured as Trunki ports. All VLANs are allowed to pass. What is needed to achieve normal communication between two hosts? () (Single-choice question)

UDP is connectionless and must rely on () to ensure the reliability of transmission.

Assuming that OSPF has been enabled on all routers in the following figure, which router is the BDR on this network?