Which equipment is critical for establishing a local area network?

A router is critical for establishing a local area network (LAN) as it serves as the central device that directs traffic between devices within the network and connects the LAN to the internet or other networks. Routers facilitate communication between multiple devices, assigning local IP addresses and managing data packets, ensuring they reach their correct destinations within the network.

While firewalls, network cables, and modems are all important components of a network, they serve different roles. A firewall provides security by monitoring and controlling incoming and outgoing network traffic based on predetermined security rules. Network cables are essential for physically connecting devices within the LAN but do not manage traffic on their own. A modem allows for internet connectivity by modulating and demodulating signals from an Internet Service Provider (ISP) to the local network, but it does not manage the internal communication between devices as a router does. Thus, the router's function in managing local network traffic and connecting the network to external networks makes it the critical piece of equipment for establishing a LAN.