Router
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Contents |
Introduction
Routers are networking devices used to tie two or more networks together. Devices that need to transmit information to outside networks pass that data to a router, which in turn forwards it through an appropriate route to its final destination. As such, routers are critical components of any interconnected network, forming the backbone of such systems.
Optional Features
In addition to the basic function described above, routers can also perform a number of more advanced tasks. Some of the more common functions are listed below.
Network Address Translation
Most residential routers perform a process called network address translation that allows all of the devices behind the router to appear as a single device to outside networks. This allows users of basic Cable and DSL broadband services to transparently share their connection between all computers in the household. In addition, it also provides a basic layer of security as unsolicited incomming network traffic is inherently rejected by this function. Please see the dedicated NAT article for more information on this topic.
Firewall
To help protect and isolate the networks behind them, many routers contain firewalls that help to filter the traffic flowing through them. Residential routers typically have basic firewall capabilities, however higher-end units may contain sophisticated systems that inspect the data travelling over the network and prevent malicious traffic from traversing them.
DHCP Server
Many routers contain a built-in DHCP server that can automatically assign network settings to devices connecting to them. This can vastly simplify the process of building a network, especially for users not experienced with the intricacies of TCP/IP networking.
Wireless Access Point
Many modern residential routers offer a built-in wireless access point that allows WiFi devices to connect to the network serviced by the router. These combonation devices are commonly referred to as 'wireless routers'. Please see the access point article for more information on this function.
Ethernet Switch
Most routers contain a small built-in Ethernet switch that allows a small network to be set up without any additional equipment. A number of devices can connect to the ports on the back of the router, and communicate with one another and the router itself. The capabilities of these switches varies from model to model, however most are simple 5-port fast ethernet switches.
DSL/Cable Tunnelling Support
Many residential routers contain the ability to communicate with encapsulation protocols used by many DSL and Cable providers. This allows these routers to connect and log into these subscription networks without additional software.
Setup
Most residential routers can be configured by entering their IP Address into a web browser. Once there, the primary features of the device can be configured as desired, although many of the default settings will generally be suitable. Each router does this in a slightly different manner, so users must consult their user manual for more information.
