Network segmentation is a way of dividing a computer network into subnetworks, each being a network segment or network layer. A big network can be segmented to smaller subnets using a Router.

By segmenting a big network into smaller subnets, we can keep the local network traffic local. Routers drop unwanted traffic originating from one network to pass through it to another network, thus increasing the bandwidth available to each user. Another benefit of decreased traffic is fewer collisions and quality network.

Another benifits of network segmentation using Routers include

Media Transition: Routers are used to connect networks of different media types.

Broadcast control: By default, routers don't pass broadcasts and therefore restrict the broadcast within the broadcast domain.