A network switch is a device that connects multiple devices within a local area network (LAN) and uses packet switching to forward data to its destination. Unlike a hub, which broadcasts data to all connected devices, a network switch intelligently directs data only to the specific device it is intended for. This improves the efficiency and performance of the network by reducing unnecessary traffic. Network switches operate at the data link layer (Layer 2) of the OSI model, but some can also function at the network layer (Layer 3), providing additional routing capabilities.

In the context of data security, a network switch can enhance security by segmenting network traffic, limiting broadcast domains, and reducing collision domains. Advanced switches can implement security features such as VLANs (Virtual Local Area Networks), port security, access control lists (ACLs), and Quality of Service (QoS) to control and prioritize traffic. By efficiently managing data flow and incorporating security measures, network switches help protect sensitive information from unauthorized access and potential cyber threats.