Establishing a Subnet in a Computer Network

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A subnet is a small network inside a larger network. It is a logical grouping of connected network devices that tend to be located in close physical proximity to each other on a local area network—a LAN.

There are plenty of times when a large network might need to have smaller networks inside of it. A simple example is a large company network with subnets for human resources or accounting departments.

Network designers employ subnets as a way to partition networks into logical segments for greater ease of administration. When subnets are properly implemented, both the performance and security of networks are improved.

A single IP address at a large business network may accept a message or file from an outside computer, but then it must decide which of the company's hundreds or thousands of computers in the office should receive it. Subnetting gives the network a logical tier or organization that can identify the correct path within the company. 

What Is Subnetting?

Subnetting is the process of dividing a network into two or more subnets. An IP address has numbers that identify the network ID and the host ID. A subnet address borrows some of the bits from the host ID of the IP address. Subnetting is largely invisible to computer users who aren't also network administrators. 

Advantages of Using Subnets

Any office or school with a large number of computers can enjoy the advantages of using subnets. They include:

  • Network performance and speed improve.
  • Network congestion is reduced.
  • Data delivery is more efficient. 
  • An organization can take full advantage of the network's capacity.
  • Network security improves.
  • Administration eases.
  • Troubleshooting can be limited to a subnet rather than the entire network.
  • The separation between different departments in an organization is maintained.

There aren't many disadvantages to subnetting. The process will likely require additional routers, switches or hubs, which is an expense. Also, you'll need an experienced network administrator to manage the network and subnets.

Setting Up a Subnet

You may not need to set up a subnet if you only have a few computers in your network. Unless you are a network administrator, the process can be a bit complex. It's probably best to hire a tech professional to set up a subnet. However, if you want to try your hand at it, check out this subnetting tutorial