Consider the figure below. The IP and MAC addresses are shown for nodes A$,$ B$,$ C and D$,$ as well as for the router's interfaces. Consider an IP datagram being sent from node A to node B$.$ Fill the encapsuled addresses at each point.Consider the LAN below consisting of $10$ computers connected by two self$-$learning Ethernet

switches. $($You may want to re$-$read section $6\mathrm{.}4\mathrm{.}3$ in the $8$th edition textbook$).$ At $t=0$ the

switch table entries for both switches are empty. At $t=1,2,3,$ and $4,$ a source node sends to

a destination node as shown below, and the destination replies immediately $($well before the

next time step$).$

Assume that the following transmissions occur $($the transmissions in reply occur but are not

shown in the list below$)$:

$t=1$:$BD$

$t=2$:$DH$

$t=3$:$FD$

$t=4$:$AJ$

Answer the questions below:

a$)$ At $t=1,$ what is the source entry for switch $1?$ Format your answer as letter,number or $\text{'}$n$/$a$\text{'}$

b$)$ At t$=1,$ what is the source entry for switch $2?$ Format your answer as letter,number or $\text{'}$n$/$a$\text{'}$