Networking - Subnetting - Discussion

Host bits required = 16.

By formula, 2^h-2 = 16.

=> 2^h = 18.

Best suited value here for h is 5.

By this sub net we get is 1111 1111.1111 1111.1111 1111.1110 0000.

255.255.255.224.

255.255.255.224 in binary would be written as:

11111111.11111111.11111111.11100000.

To find number of host:

Starting from the octet consisting both 1 and 0.

Count number of zeros to the end of the subnet mask.

The last octet consist of 5 zeros therefore.

2^h-2 (h = number of zeros) = 2^5-2 = 32 -2 = 30.

To find number of sub nets:

2^n (n = number of ones) 2^3 = 8.

Is there a possibility of using only the subnets and host values given in the question to get the subnet mask rather than testing the answers one after the other to get a match?

Network bits = 3.
Host bits = 5.

Formula:

To find number of subnet = 2^n(n = no>of borrowed network bits).
To find no.of host = 2^h-2(h = no>of borrowed host bits).

How 255.255.255.224 provides 8 subnets ,each with 30 hosts? how could it be?

Yes I agree but nobody tell me how we create subnetting?