If a office network want to divided into 30 sub networks then what is a right Subnet mask ?
(a) 255.255.255.240
(b) 255.255.255.248
(c) 255.255.255.224
(d) 255.255.255.254
Answer :- (b)
Explanation :-
30 subnet not possible you should use subnet in 2’s power combination
2^5=32
5 bit used for Network Portion and you should borrow 5 bits from host portion
if we use 4 bit then only 2^4=16 subnet will possible hence 5 bit required for build correct subnet mask
the Subnet mask will be
11111111.11111111.11111111.11111000
255.255.255.248
Correct Answer (b)
