Computer Networks

Question

Given answer (FROM PW) 4^th  = 5

5^th = c

I don’t understand 4^th question properly.

For the 5^th I am getting c and d as answer.

Explanation.

Since 2 bit is used for subnet mask:

then total 4 subnet possible:

1 = 152.158.0.0 to 152.158.63.255

2 = 152.158.64.0 to 152.158.127.255

3 = 152.158.128.0 to 152.158.191.255

4 = 152.158.192.0 to 152.158.255.255

 

Let me know where I am wrong.

Comments

4. Given IP is from Class C, 24 bits are NID and 1’s in the subnet mask will give us #bits in subnet ID, $(240)_{10} = (11110000)_2$, therefore we have 4 bits of subnet ID.
   Total #subnets = $2^4 = 16$
   Let’s do AND between given IP and subnet mask to get Network ID
   $193.200.250.68 \text{ } \& \text{ } 255.255.255.240 = 193.200.250.64$
   $(64)_{10} = (01000000)_2$, subnet ID bits are = $0100$ which is our 5^th subnet
   ($0000$ is 1^st subnet, $0001$ is 2^nd subnet and so on)
    
5. Given IP is from Class B, so $16$ bits are NID and according to subnet mask $2$ bits are subnet ID and $14$ bits are host ID.
   After doing AND of IP and subnet mask we get Network ID = $152.158.0.0$ so DBA = $152.158.63.255$
   Notice DBA will be $152.158.255.255$ when we don’t know about subnetting or subnetting has not been done in that case subnet mask would be $255.255.0.0$
    

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4: no of subnet possible =14

Given subnet should be of no 4.

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@Onika Y

 

answer given by @Aditya_ is correct.

See 240 is used in subnet mask which is equal to (11110000) in binary.

So 4 bit is used for subnetting.

number of subnet possible = $2^{4}$ = 16.