Subnet

A subnet is a logically visible subdivision of an IP network.

How Does Subnetting Work?

Subnetting is the technique for logically partitioning a single physical network into multiple smaller sub-networks or subnets.

Subnetting enables an organization to conceal network complexity and reduce network traffic by adding subnets without a new network number. When a single network number must be used across many segments of a local area network (LAN), subnetting is essential.

The benefits of subnetting include:

• Reducing broadcast volume and thus network traffic
• Enabling work from home
• Allowing organizations to surpass LAN constraints such as maximum number of hosts

Classes of Subnet

Class A, B, and C networks have natural masks, or default subnet masks:

• Class A: 255.0.0.0
• Class B: 255.255.0.0
• Class C: 255.255.255.0

You can determine the number and type of IP addresses any given local network requires based on its default subnet mask.

What Does IP Mask Mean?

“IP/Mask” as a shorthand to define both the IP address and submask at once. In this situation, the IP address is followed by the number of bits in the mask. For example:

• 10.0.1.1/24 = IP of 10.0.1.1 with subnet mask of 255.255.255.0
• 216.202.192.66/22 = IP of 216.202.196.66 with a subnet mask example of 255.255.252.0

However, you do not mask the IP address, you mask the subnet.

Related

• More notes in Subnet Mask