D-Link DI-713P - Manual (Page 6)

6
Introduction to Broadband Router Technology
A router is a device that forwards data packets from a source to a
destination. Routers work on OSI layer 3, which forwards data packets
using an IP addresses and not a MAC address. A router will forward data
from the Internet to a particular computer on your LAN.
The information that makes up the Internet gets moved around using
routers. When you click on a link on a web page, you send a request to a
server to show you the next page. The information that is sent and received
from your computer is moved from your computer to the server using
routers. A router also determines the best route that your information
should follow to ensure that the information is delivered properly.
A router controls the amount of data that is sent through your network
by eliminating information that shouldn’t be there. This provides security
for the computers behind your router because computers from the outside
can’t access or send information directly to any computer on your network.
The router determines which computer the information should be
forwarded to and sends it. If the information isn’t intended for any
computer on your network, the data is discarded. This keeps any unwanted
or harmful information from accessing or damaging your network.