What are the functions of subnet mask?

Answer 1

The function of a subnet mask is to extract the network ID portion of an IP destination address and determine whether an IP address exists on the local network or whether it must be routed outside the local network

Answer 2

Main role of the Subnet mask is to give you the Subnet (network) address of your network. For a given I.P. (internet Protocol ) Address say of any class it can be divided into different smaller groups. For E.g. I.P. Address = 192.56.78.24 it is a class C address. Now Anding the I.P. address with given Subnet mask say 255.255.255.o gives you the network ID of the Address i.e. 192.56.78 . Note to making the Anding you need to convert both the address into their binary values and then AND them after that convert back to decimal value. 192 , 56, 78 , 24 should be separately converted.

Answer 3

A subnet mask sends messages to the computer. Its main function is to let the computer know which addresses are remote, and which are local.