Find the subnet Network ID and valid host ID range for each

Find the subnet (Network ID) and valid host ID range for each of the following pairs of IP address and subnet mask. (a) 172.16.10.15/255.255.255.128 (b) 106.126.0.123/255.192.0.0 Find the subnet mask for each of the following networks. (c) a Class A network with 500 subnets (d) a Class C network with 12 subnets

Solution

Part-II:-

(C) We know that class A subnet mask:255.0.0.0

Required Subnets =500
2^8=256 Which is less than the required number of Hosts

2^9=512 Which will full fill the requirement.
so network bits=9 are added to given submnet mask.
i.e.., 255.11111111.1000000.00000000
now subnet mask is:255.255.128.0

(D):-
class C subnet mask:255.255.255.0
Required Subnets =12

2^3=8

2^4=16

so network bits=4 are added togiven submnet mask.
i.e.. 255.255.255.11110000
now subnet mask is:255.255.255.240