Routers

Routers are networking devices that forward data packets between different networks. They operate at the network layer (layer 3) and determine routes using routing tables and protocols. In homes and small offices, a router connects a local area network to a wider network or the Internet, and often provides additional services such as network address translation, firewall protection, and DHCP server functionality.

Routers come in several forms. Consumer devices combine routing, switching, and often wireless access point functions in a single box. Enterprise and service provider routers handle higher traffic, multiple WAN links, VPNs, and advanced routing features. Core routers operate inside large networks, while edge routers connect internal networks to external ones and may terminate external connections.

Routing can be static or dynamic. Static routing uses fixed paths configured by an administrator, while dynamic routing relies on protocols such as RIP, OSPF, EIGRP, and BGP to adapt to topology changes. BGP is the primary interdomain protocol on the Internet. Routers build routing tables from reachability information and forward packets toward the next hop. Network address translation and basic firewall functions are often integrated into routers.

Hardware and management. Routers contain a central processor, memory, and storage to run operating systems and routing software. Interfaces typically include Ethernet ports for LAN and WAN, with some models adding wireless radios, SFP ports, and redundant power. Administration is provided via web interfaces, command-line interfaces, or centralized management systems. Security best practices include timely firmware updates, disabling unused services, and strong access controls.