In today's world of (ever increasing) high-speed internet access a router is an essential part of your PC equipment, whether it be at home or in a small office environment. This is a brief summary of as to what a router is and how it performs its tasks.
So what is a router?
A router is a piece of electronic equipment that moves data through computer networks; it controls the direction of of flow of data (or 'traffic') on the internet and also on local area networks (LAN). For a router to work it needs to be connected to at least two machines that are transferring data, eg. two PCs. As data is being shared between the two devices, the router reads the 'address' information in each data packet. This is then used by the router to determine the data's destination.
As a simple example, a data packet is typically passed from router to router through the various networks of the internet until it gets to its final destination computer.
The more familiar type of router are those that are classed as home routers and/or small office routers. These simply pass data, for example email or web pages, between the DSL or cable modem and the home/office computer. Routers can either be a wired router ie. physically connect to the user's computer via an Ethernet cable, or they can be a wireless router.
Since the decline of dial-up internet access and the massive growth of broadband internet connections, coupled with the fact that many homes and small offices have more than one PC, broadband routers have become a necessity.
Routers and security.
With exponential growth of the internet, security is a major factor with routers. Before the advent of modern day routers a firewall tended to be software based on the user's computer (external firewalls did and still do exist). Many routers now have their own built-in firewalls, sometimes along with various other security functionalities, offering an increased level of security.
Unless defined by the user as otherwise, a wireless router can only be accessed via the use of a password. Earlier wireless routers used a security protocol known as WEP (Wired Equivalent Privacy). It was later discovered that WEP had serious security weaknesses allowing (relatively) easy access to even a password protected router using the WEP protocol, thus allowing hackers within the vicinity of the router's signal to be able to 'steal' someone else's internet connection. WEP was later superseded by the far superior WPA (Wi-Fi Protected Access) and, later still, by WPA2 (Wi-Fi Protected Access II).