IP addressing

Question

In class C , if subnet mask is 255.255.255.224 then calculates number of subnet?

Comments

it is a class C NETWORK
class c default subnet mask : 255.255.255.0

here subnet mask :255.255.255.224
  which  is represented as 11111111.11111111.11111111.1110 0000
so no of subnet bits  which are borrowed from host bit: 3

no of subnet : 2^n -2
here we are subtracting 2 because host part cannot be all one and zero

so according to above ques no of subnets : 2^3 -2 = 8-2 :6

Answer 1

If we do not consider Subnet Zero and the All-Ones Subnet, then No. of subnets = 2^{subnet bits} - 2 = 2³-2 = 6,

and regarding Subnet Zero and the All-Ones Subnet

http://www.cisco.com/c/en/us/support/docs/ip/dynamic-address-allocation-resolution/13711-40.html

Answer 2

For finding no. Of subnet firtly we will find how many bits r used for subnetting that we will know by subnet mask .

Here 255.255.255.224

subnet bits r borrowed from host part

So 11111111.11111111.11111111.11100000

here 3 bits r borrowed from host part so number of subnets is 2^3-2

this minus two is just becuse 255.255.255.0 is network mask of class c and when all 1's then it will be dba of network

Answer 3

Class C network.. So fourth octate is used for subnet ..

224 =11100000 so 3 bits are borrowed..

2^3 subnets are possible and each subnet contains 2^5 - 2 user id's...