What is network segmentation, and why is it used?

Network segmentation is the practice of dividing a computer network into subnetworks, each being a network segment or subnet.

Network segmentation is a key strategy in network design and management. It involves splitting a network into smaller parts, known as segments or subnets. This is done for a variety of reasons, including improving performance, enhancing security, and easing management.

In terms of performance, network segmentation can help reduce network congestion. By dividing a large network into smaller subnets, the amount of traffic on each subnet is reduced. This can lead to improved network performance, as fewer devices are competing for network resources. For example, if a large organisation has a single network that all devices connect to, it can become congested and slow down. By segmenting the network, the organisation can ensure that traffic is more evenly distributed, leading to better performance.

Network segmentation also enhances security. Each segment can have its own security policies and controls, which can limit the spread of malware or a cyber attack. If an attacker gains access to one segment, they may not be able to move onto other segments if appropriate security measures are in place. This is known as 'limiting the attack surface'. For instance, a company might have a segment for its finance department that is separate from other departments. If the finance segment is compromised, the attacker would not be able to access information in other segments.

Finally, network segmentation can make network management easier. By breaking a network down into smaller, more manageable pieces, network administrators can more easily monitor and control each segment. This can make it easier to identify and resolve issues, as well as implement changes. For example, if a company needs to update its network security policies, it can do so on a segment-by-segment basis, rather than having to update the entire network at once.

In conclusion, network segmentation is a valuable tool for improving network performance, enhancing security, and simplifying management. It is a strategy that is widely used in both small and large networks.