Which device is commonly used to segment a network?

A switch is commonly used to segment a network because it operates at the data link layer (Layer 2) of the OSI model. By receiving data packets and making intelligent decisions to forward them only to the specific device on the network that requires that data (rather than broadcasting it to all devices), switches create separate collision domains. This not only improves network performance by reducing collisions but also enhances security by isolating traffic within specific subnets or segments.

In contrast, a router is primarily used to connect different networks and operates at the network layer (Layer 3) of the OSI model. While routers do provide some level of segmentation, their main function is to route traffic between different networks rather than segmenting traffic within the same network.

Hubs are basic networking devices that broadcast data to all devices connected to them, offering no segmentation and, therefore, no improvement in performance or security.

Repeaters are used to regenerate and amplify signals to extend the distance over which data can travel but do not inherently provide any network segmentation. Thus, while they improve signal strength, they do not create separate segments within a network.

Overall, the unique functionality of switches in managing traffic efficiently makes them essential for network segmentation.