computer network Subnet Mask

Question

A class C network is assigned with a subnet mask of 255.255.255.248 . The total number of hosts possible in all the sub networks together in the above network is .......

Please help me to find the answer...

Answer 1

Given ,

Subnet mask  = 255.255.255.248 and the network is given to be of class C..

So number of subnet bits  =  5

Hence number of subnets  = 2⁵   =  32

Number of host bits for each subnet  =  3

Hence number of hosts in each subnet  = 2³ - 2  = 6

Hence total number of hosts  = Number of subnets * number of hosts in each subnet

                                           = 32 * 6

                                           = 192

Comments

In general the number of available hosts on a subnet is 2^h−2, where h is the number of bits used for the host portion of the address. The number of available subnets is 2ⁿ, where n is the number of bits used for the network portion of the address. This is the RFC 1878 standard used by the IETF, the IEEE and COMPTIA.

https://en.wikipedia.org/wiki/Subnetwork#Subnet_zero_and_the_all-ones_subnet

Answer 2

Given ,

Subnet mask  = 255.255.255.248 and the network is given to be of class C..

So number of subnet bits  =  5

Hence number of subnets  = 2⁵  =  32 [According to new RFC convention]

Number of host bits for each subnet  =  3

Hence number of hosts in each subnet  = 2³ - 2  = 6

Hence total number of hosts  = Number of subnets * number of hosts in each subnet

                                           = 32 * 6

                                           = 192

Hence 192 should be the correct answer..

Answer 3

as it is class C , 5 bits will be used for subnet
no of subnet will be : 2^5=32

no of host per subnet : 2^3-2=6

total # of host: 32*6= 192