KUMEL'S NOTE

Subnetting is a technique to break up a large network into smaller networks by sacrificing bit Host ID on the subnet mask to be used as a new Network ID.
example:IP address 192.168.10.0 with a subnet mask 255.255.255.0 default is defined as a class C which means that IP address without subnetting a network address has only one fruit with 254 IP addresses that can be made (192.168.10.1 / 192.168.10.254).

Now we will divide the existing network into several the subnetwork using subnetting techniques by replacing a few bits of Host IDs that exist on the subnet mask with the number 1.
Before subnetting:
IP address: 192.168.10.0
Subnet Mask in Binary: 11111111.11111111.11111111.00000000
Subnet Mask in Decimal: 255.255.255.0
After Subnetting Being:
IP address: 192.168.10.0
Subnet Mask in Binary: 11111111.11111111.11111111.11000000
Subnet Mask in Decimal: 255.255.255.192
1. Determining the number of subnets (Sub Network) has formed. use the formula 2^n-2 where n is the number of 1 bits in the host ID that has been modified (11000000), the importance of the 2^n-2=2. so the IP 192.168.10.0 2 subnets obtained after subnetting new.
2. Determine the Number of Hosts of subnets, use the formula 2^h-2, h is the number 0 on the host ID bits (11000000), then on to 2^h-2=62, so there are 62 hosts persubnet. or in other words from two groups of the subnetworks, each the subnetwork can accommodate 62 computers with different IP addresses.
3. Determining Block subnet and IP address ranges Block subnet is obtained by subtracting 256 (2^8) with the numbers behind the subnet mask that has been modified, 256-192=64, then total the number of these reductions to the same subnet behind the numbers in order to get 64+64=128, 128+64=192. so the IP address that is applied to two new the subnetwork is 64:
192.168.10.64 / 192 168 127, the first subnet
192.168.10.128 / 192 168 191, the second subnet
4. Determining the IP Address that can be used. From the range of IP addresses on each subnet above are not everything can be used as a Host IP address:
Sub-network 1.
Subnet address: 192.168.10.64
The first Host Address: 192.168.10.65
Last Host Address: 192.168.10.126
Broadcast Address: 192.168.10.127
Sub-network 2.
Subnet address: 192.168.10.128
The first host address: 192.168.10.129
Last Host Address: 192.168.10.190
Broadcast Address: 192.168.10.191
=>Simplification of managers: a remote network, the large number of computers that must connect will be made easier to manage when the network itself rather than have to be one big network.