Computer Networks MCQ - Computer Networks Section 3

21 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. Router R1 has IP addresses 192.168.1.135 and 192.168.1.110. R2 has IP addresses 192.168.1.67 and 192.168.1.155. The netmask 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

Given IP addresses are of Class C
default Mask for class C = 24
The given mask is 11 bits 11111111 11111111 11111111 11100000
subnet ID: 3 bits
existing subnets: 011, 010 and 100

22 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. Router R1 has IP addresses 192.168.1.135 and 192.168.1.110. R2 has IP addresses 192.168.1.67 and 192.168.1.155. The netmask used in the network is 255.255.255.224.
Which IP address should X configure its gateway as?

For ip address 192.168.1.110/28
For network address keep Network bits as it is and put host bits =0 in any given IP address.
Network address
= 192.168.1.01100000 ⟶ 192.168.1.96
For: 192.168.1.97/28
Network address
= 192.168.1.01100000 ⟶ 192.168.1.96

23 If a class B network on the Internet has a subnet mask of 255.255.248.0, what is the maximum number of hosts per subnet?

Starting address : 255. 255. 248.0
End address : 255. 255. 255. 254.

24 Suppose computers A and B have IP addresses 10.105.1.113 and 10.105.1.91 respectively and they both use the same netmask N. Which of the values of N given below should not be used if A and B should belong to the same network?

Given : 10.105.1.113 and 10.105.1.91
When these are in same network, then AND with netmask give the address of same ID otherwise these are in different class in these only AND with 255.255.255.224 are in different class
This is 96 and 64. Then these are different ID means 10.105.1.96 and 10.105.1.64 are different ID. So this is not in same network.

When we do the similar operation with 2nd IP, it gives 10.105.1.64
Here, it gives different IP
but for the rest it gives same IP.

25 In the I Pv4 addressing format, the number of networks allowed under Class C addresses is

For class C address, size of network field is 24 bits. But first 3 bits are fixed as 110; hence total number of networks possible is 2²¹