What is the length of the Ethernet_II frame containing the Ethernet header?

Before the STA associates with the AP, it needs to exchange some messages to obtain the SSID. What are these messages?

As shown in the figure, RTA uses NAT technology and realizes multiple-to-multiple NAPT address translation by defining an address pool, so that hosts in the private network can access the public network. Suppose that there are only two public IP addresses in the address pool, and they have been assigned to hosts A and B for address conversion, and if host C also wants to access the public network, which of the following description is correct?

Switches running SIP protocol, the port needs to wait for the forwarding delay in the Learning state before it can be transformed into the Forwarding state.

What is the Solicited-node multicast address corresponding to IPv6 address 2019:: 8:AB?