7. Consider the following network interconnected by one router, R1, and a set of switches,
S1, S3, S4, S5, as are shown in Figure below. (4 Ă— 5 = 20 points)
A
C
E
S5
S4
S3
X
B
F
S1
R1
D
Subnet 1
Subnet 3
a) How many subnets are there in this network shown in the above figure, and which
computer hosts (A, B, C, D, E and F) are attached to each subnet? Please briefly
explain your answer.