Information Technology Reference
In-Depth Information
Understanding and Connecting
to.the.Internet
The Internet began as a way of enabling research institutions and the
military to share information. Today, however, it is the largest and
most-used network in the world, and it is used not only by schools and
governments but by businesses, non-profit organizations, and individu-
als in every country and of every profession. You can use the Internet
to look up information on the web, send and receive email, exchange
instant messages, upload and download files, and much more. You
will learn more about the uses of the Internet in
Chapter 9, “Online
Communication,”
and
Chapter 10, “Web Basics.”
Internet Structure
Structurally, the Internet is a mesh of routers and servers connected to
one another at multiple points, as illustrated in Figure 8.9. This makes
the Internet very fault-tolerant. If any single router or server goes down,
network traffic is simply routed around the point of failure.
© iStockphoto.com/iSergey
Figure.8 9
A mesh network does not rely on any one point being active; traffic
can easily route around any blockages.
Internet Speed
The Internet itself does not have a fixed speed. Data travels through the
Internet as fast as it can go on whatever cable it travels through, and a
single data packet may travel at different speeds during different parts
of its journey. At the heart of the Internet are high-capacity, high-speed
data pathways that are like superhighways for data. These pathways form
the Internet's
backbone
. The backbone is made up mainly of fiber optic
cables that can carry data very fast—literally at the speed of light! Large
ISPs have entire buildings full of servers that are connected directly to
the Internet off of this main backbone. From the ISP's servers to the
individual neighborhoods and individual homes and businesses, the con-
nection speeds are lower because the cheaper copper-based cables used in
those areas carry data at a lower rate. Some ISPs charge different prices
backbone
The central connection pathways of
a network, where connection speeds are high and
the data pathway is wide.
