Consider a network with four hosts, A$,$B$,$C$,$D all connected to a switch. Assume A$,$B$,$C$,$D were

all configured to know one another$$s MAC addresses. Let the first four messages $($frames$)$ sent

between the hosts be:

A $->$ D

B $->$ A

D $->$ A

A $->$ D

For each of these, when the switch receives the frame, where does it forward it to$?$

b$)$ Now suppose A actually didn$$t know D$$s MAC address, only D$$s IP address, and had to use

ARP to learn it before performing that first A $->$ D transmission. When the switch receives the

frame for that A $->$ D transmission now, where will it send it$?$ Explain briefly.