A router is a network device specifically designed to connect multiple networks and route traffic between them. Routers operate primarily at Layer 3 (the Network Layer) of the OSI model and use IP addresses to determine the best path for data packets.
Routers are commonly used to connect local area networks (LANs) to wide area networks (WANs), such as connecting an internal corporate network to the internet. They also play a role in enforcing network security by supporting access control lists (ACLs), network address translation (NAT), and routing policies.
Switches, while important, typically connect devices within the same network and operate at Layer 2. Servers and endpoints are hosts, not networking devices. Without routers, communication between separate networks would not be possible, severely limiting scalability and connectivity.
From a security perspective, routers help segment networks, reduce broadcast traffic, and control data flow, making them essential components in both performance and security architectures.