$1.$ You are setting up a small office which has $3$ vlans for security: vlan $100($ unprivileged$),$ vlan $200($administrative staff$)$ and vlan $300($servers$).$ Create a network diagram for your design. a$)$ How many subnets are required for it$?$ b$)$ Will you need a firewall? Why or why not? $2.$ Suppose an $802\mathrm{.}11$b station is configured to always reserve the channel with the RTS$/$CTS sequence. Suppose this station suddenly wants to $$transmit $5,000$ bytes of data, and all other stations are idle at this time. As a $$function of SIFS and DIFS, and ignoring propagation delay and assuming no bit errors, calculate the time required to transmit the frame and receive the acknowledgment. $3.$ Which version of cellular standard encrypts the IMSI number?

a$)3$G

b$)4$G

$9)5$G

d$)$all of the above $4.$ VLANs are attributes in $\_\_\_\_\_\_\_$ which are attached to frames and forwarded between trunk ports.

A$)$ stamps B$)$ header fields C$)$ attachments D$)$ none of these