A router is a device that connects a ‘Wide Area Network’ (WAN) to a ‘Local Area Network’ (LAN).
In English: It connects and external network (The internet, your ISP, your company’s giant network) to an internal network (several PC’s in your home, your small business network, a few isolated computers at your work).
A router will have a port (or connection plug-in) labelled ‘WAN’ and several labeled ‘LAN’.
You can think of a router as a ‘star’ that distributes network traffic from a central connection to a bunch of other connectons.
In the process a router can also provide several other services such as:
* DHCP: assigning IP addresses (the numeric network address of each computer or device).
* DNS: looking up the names of other computers in the internet and converting to a numeric address.
* Gateway: The path through which your network traffic must go to get to get to the rest of the network (it almost has to do this).
* Firewall: Keeping other computers from getting to your computers.