The Importance of Routers
By Andy Walton
The router is a fundamental building block of modern business networks, providing traffic with a gateway to both the Internet and other networks. Routers make flexible cross-network communication possible, and allow larger networks to remain operational even during redesigns or outages. They can also play important secondary roles on a network, with many combined with other devices such as firewalls, modems and switches to product versatile all-in-one networking solutions.
A router often acts as the default gateway for the computers (somethings known as “hosts”) on a LAN. This means that when a host wants to contact another host on a different network, it simply sends that traffic to the router. That router then uses a dynamically generated map of the surrounding network known as a routing table to work out where the data should be forwarded to. This process is repeated as many times as necessary until the data reaches its destination.
Routers can help to limit traffic by preventing hosts from being able to talk to each other at once. Most LANs allow hosts to communicate through broadcast, whereby a host sends traffic to every other host on its network. This is fine for small networks, but can create congestion as more hosts are added. Using routers as gateways to break networks up into smaller parts restricts the number of hosts a given host can broadcast to at any one time.
Many routers now feature the capabilities of a wireless access point, allowing them to broadcast a Wi-Fi signal to surrounding devices. Wireless routers work in the same way as their wired counterparts, but communicate over a wireless LAN rather than a wired one. This allows for a convenient networking setup in homes and small offices, as the same device is used to communicate with external networks (usually through a DSL or cable connection) and manage wireless traffic.
The router's place on the edge of a network makes it an ideal location for additional network services. Many routers offer firewall functions, checking traffic as it enters and leaves a network. A router may also act as a network switch, using Ethernet ports to direct intra-network traffic. Combined modem-routers are also common. These devices do not need an external modem to communicate over a DSL or cable line, meaning that the router may be the only piece of additional hardware needed to set up a small network.
Andy Walton has been a technology writer since 2009, specializing in networking and mobile communications. He was previously an IT technician and product manager. Walton is based in Leicester, England, and holds a bachelor's degree in information systems from the University of Leeds.