What is a collision domain in networking?

A collision domain refers to a network segment where packets can collide due to multiple devices attempting to send data over the same network channel simultaneously. In this context, when devices share a communication medium, like in older Ethernet networks, if two devices send packets at the same time, those packets interfere with each other, leading to a collision. The concept is essential in understanding how data transmission works in shared network environments, especially in networking technologies that operate under the carrier-sense multiple access with collision detection (CSMA/CD) protocol.

Reducing the size of collision domains can enhance network performance, which is why switches and routers are used in modern networks to break collision domains into smaller segments, allowing more efficient communication without collisions.