This document defines and compares common networking devices and terms. It discusses hubs, switches, routers, bridges, gateways, network interface cards (NICs), and modems. Hubs are basic devices that connect networked devices but do not monitor traffic or activity. Switches are more intelligent devices that can direct traffic to specific ports. Routers connect different networks and use routing tables to determine the best path for traffic. Bridges and gateways also connect different networks using different protocols.