Networking and Internet Basics - Computing Fundamentals - page 215

Summary
Our Connected World: Communication Systems
Networking is everywhere. A computer network is a packet-switched network , which sends and
receives data in packets that may take different routes to the destination.
The Internet is the world's largest network. It uses various standard protocols , so that services
like the web and email work the same everywhere. Most companies don't connect directly to the
Internet; instead they connect to an Internet service provider (ISP) .
The Internet is based on a protocol stack (a set of protocols) called Transmission Control
Protocol / Internet Protocol (TCP/IP) . TCP/IP provides a common set of standards by which
data can be sent and received. It is used not only on the Internet, but in most private networks
today as well.
To tighten security when using the Internet as a conduit, many companies use a software technol-
ogy called virtual private networking (VPN) . VPN technology creates a secure, tamper-resistant
data tunnel between two points on the Internet.
A satellite is a transmitter/receiver unit that orbits the Earth, thousands of miles up. Satellite
networks are used to deliver services such as TV and video broadcasts, satellite radio, and
satellite Internet service. Cellular telephone companies have their own data networks, using a
combination of satellites, cables, and on-ground towers with transmitters and receivers on them.
Some cell phone networks can also be used to access the Internet. You can access the Internet on
a smartphone (a cell phone that includes computer functionality), and you can tether (connect) a
smartphone to a computer and use the phone as a modem to allow the computer Internet access.
Ways of.Classifying Networks
There are several ways to classify computer networks. One way is according to the geographical
range that they cover: personal area network (PAN) , local area network (LAN), metropolitan
area network (MAN), or wide area network (WAN) . Another way is to look at whether or not
a server is involved. In a peer-to-peer network , there is no server; in a client/server network ,
there is at least one server.
An intranet is a network accessible only from inside a company. An extranet is a network that is
for the use of those outside the organization.
Ethernet is the most popular Internet technology, having outlived many competitors. Ethernet
can be wired or wireless; the wireless version is also called Wi-Fi . Ethernet devices have a certain
maximum speed.
A wired connection runs a cable between the points, whereas wireless connects the two points via
radio frequency (RF) or infrared. Wi-Fi is short for wireless fidelity. It's the common name for
the wireless networking technology that's used for almost all home and business networks today,
often referred to by its standard number: IEEE 802.11. Bluetooth is a wireless technology used
to connect individual devices to one another in close proximity. It is most commonly used to con-
nect a computer to an input or output device. When the devices are within range, they are paired .
Infrared technology uses light waves to “beam” information from device to device. Infrared was
the method of choice for connecting wireless peripherals a decade or so ago, but Bluetooth has
mainly superseded it today. A microwave communication system allows two locations to be wire-
lessly connected by using a high-frequency communication band, much higher than that used for
Wi-Fi or Bluetooth.