Question

Host X has IP address 192.168.1.97 and is connected through two routers R1 and R2 to another host Y with IP address 192.168.1.80. RouterR1 has IP addresses 192.168.1.135 and 192.168.1.110. R2 has IP addresses 192.168.1.67 and192.168.1.155.The network used in the network is 255.255.255.224.

Given the information above, how many distinct subnets are guaranteed to already exist in the network?

• A. 2
• B. 6
• C. 1
• D. 3

Answer 1

The correct option is A 2

By performing bitwise AND between given IP addresses and subnet mask such as
$\begin{array}{cc}\mathrm{192.168.1.97}& \mathrm{192.168.1.80}\\ \underset{–}{\mathrm{255.255.255.224}}& \underset{–}{\mathrm{255.255.255.224}}\\ \mathrm{192.168.1.}\underset{–}{011}00001& \mathrm{192.168.1.}\underset{–}{010}10000\end{array}$

$\begin{array}{cc}\mathrm{192.168.1.135}& \mathrm{192.168.1.110}\\ \underset{–}{\mathrm{255.255.255.224}}& \underset{–}{\mathrm{255.255.255.224}}\\ \mathrm{192.168.1.}\underset{–}{100}00111& \mathrm{192.168.1.}\underset{–}{011}01110\end{array}$

$\begin{array}{cc}\mathrm{192.168.1.167}& \mathrm{192.168.1.155}\\ \underset{–}{\mathrm{255.255.255.224}}& \underset{–}{\mathrm{255.255.255.224}}\\ \mathrm{192.168.1.}\underset{–}{010}00011& \mathrm{192.168.1.}\underset{–}{100}11011\end{array}$
Their are 3 distinct subnet present i.e, 011, 010, 100.
So answer should be option (b)