4 Things You Should Know About Subnetting

Subnetting is a system where a single network is partitioned into several small logical sub-networks known as subnets. An IP address is inclusive of a host segment and a network segment. A subnet can be designed by accepting an IP address host bits and using them to assign several smaller sub-networks into the original network.

Subnetting aids in concealing network complexity and reducing network traffic. It comes in handy when you want to allocate a single network number on several segments of a LAN. The initial purpose of their design was to solve the issue of IP address shortage on the internet.

With that basic understanding in mind, here are 4 things you should know about subnetting:

  1.    The 1s And 0s

Subnetting entails adding bits to an original subnet mask to create additional networks. When you convert a subnet mask to a binary form and add extra 1s, you’ll have subnetted that network.

The more 1s there are in a subnet mask, the more networks there will be with less number of hosts. The more 0s there are in a subnet mask, the lesser networks there will be and the more the hosts you’ll have.

Subnet masks inform computers and routers which IP address portion is for the host and which portion is for the network.

  1.    Subnet Masks Are Written In Two Ways

You can write subnet masks in two ways. The first is the dotted decimal notation method. It entails writing numbers and using dots to separate them. A Class C default subnet mask, for example, would be written as

The second method is the slash notation method where the subnet mask is converted to a binary form by writing the 1s in the subnet mask. in binary form would be written as 11111111 11111111 11111111 00000000.

This would translate to /24 in slash notation, that is, the number of 1s. An IP network in slash notation with a subnet mask would hence be written as

  1.    Subnetting Reduces Network Congestion

Subnetting plays a role in ensuring that the traffic within a subnet that is destined for a device stays in the subnet, thereby reducing congestion. By placing subnets strategically, you reduce the network load and route traffic more efficiently.

If a large network has no subnets, the result will be that all computers will be able to see broadcast packets from all servers and computers present on the network. The switches will then have to move that traffic to the right ports which will result in congestion.

Moving traffic between subnets via a router however will result in no broadcast traffic or unwanted information moving to other subnets. With the reduction of traffic within each subnet, their speed will increase, thereby reducing network congestion.

  1.    Subnetting Boosts Network Security

Splitting your network to subnets allows you to control the traffic flow via QoS, route-maps, or ACLs. This way you can be able to identify threats, close all the entry points, and easily target all your responses.

You can use routers to split your network by connecting subnets through configuring the ACLs on the switches and routers. By so doing, you prevent the devices on the subnet from accessing the entire network. You can also limit wireless clients from accessing resources. This way, you’ll have secured valuable information from being accessed from remote locations.


With that valuable information in mind, here’s how to set up a network subnet.

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