Why do we use subnets

Having your entire network in one subnet could seem easier, but what if a device in that network gets compromised? Your entire network, and all of the devices within it, immediately become visible.

If you break the network into different subnets, you are able to control the flow of traffic through the network using ACLs, QoS , or Route-maps. You'll be able to easily identify threats, shut down points of entry, and target your response. It is possible for you to split up your network using one or more routers to connect subnets together, through configuring the ACLs on routers and switches.

Configuring these routers means that devices in a subnet will not be able to access the entire network. This way, all employees don't have full access to the payroll machines, for example. Or you can limit access to resources on all wireless clients, so that valuable information isn't readily accessible in remote locations.

If you aren't using subnets in your network, a single broadcast packet will send out information that will reach every device connected to that network, due to each device having an entry point into the network.

A large list of entry points reduces your internetwork switching device performance, along with your overall network performance. A single broadcast packet also effectively spams all devices within the network, even the ones that aren't relevant to the information at hand. This could bring your network's capacity to its peak, leading it to collapse due to excessive collisions of information. And you know you'll be getting a call about that. Subnetting, however, will help the information remain in the subnetted network or the broadcast domain, freeing up other subnets to use on their speediest and most effective capabilities.

It will also divide up your broadcasting domains and control your traffic flow, which will increase your network performance. It is advantageous to keep traffic on a single subnet, instead of letting that traffic flow from one subnet to another.

To gain better network performance and speed, you need to reduce the number of devices on a subnet and control the flow of traffic between subnets. You are able to create networks with more realistic host limits, as opposed to the limits imposed by IP addressing classes 8 bits for Class A, 16 bits for Class B, and 24 bits for Class C. If the internet were limited to Class A, B, or C addresses, every network would only have either , 64,, or 16 million IP addresses for host devices.

It also allows you to minimize the size of the routing tables stored in the routers. It also broadens the existing base of IP addresses and restructures the IP address.

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Therefore, subnetting is like creating separate conference rooms to discuss each individual topic. With less devices on the network, communication becomes vastly more efficient and effective. Even for experienced network administrators, managing a network is a stressful task. Subnets allow administrators to isolate certain devices into logical groups. This allows the network administrator to determine which group of devices need attention right away.

In addition to logical groups, hosting on subnets is much more efficient for network administrators. This is because of host limits and address allocation; instead of having one network with a limit of 16 million IP addresses, there could be hundreds of networks with 64, addresses, which would take much less time to parse through.

By breaking it up into multiple networks, an administrator has the ability to isolate the compromised network s. With the ability to isolate the compromised network, the network administrator can prevent further damage to the network and work on addressing the problem at hand.

Rather than having all resources on one network, it is safer for an administrator and upper management to have a network with the resources that only they have access to. Information is valuable, so all the important information should be separated from possible perpetrators.

Its benefits range from network speed enhancement all the way to protecting valuable information. Business Management.