Class of network

 Network Types 

 C learly, different types of channels—wired or wireless—allow different kinds
of networks to be formed. Telephone lines, for instance, may connect communications equipment within the same building or within a home. Networks
also may be citywide and even international, using both cable and wireless
connections. Local area, metropolitan area, and wide area networks are distinguished by the geographical area they serve.

 Local Area Networks 

Networks with nodes that are in close physical proximity—within the same
building, for instance—are called local area networks (LANs). Typically,
LANs span distances less than a mile and are owned and operated by individual organizations. LANs are widely used by colleges, universities, and other
types of organizations to link microcomputers and to share printers and other
resources. For a simple LAN, see Figure 9-16 .
The LAN represented in Figure 9-16 is a typical arrangement and provides two
benefits: economy and flexibility. People can share costly equipment. For instance,
the four microcomputers share the laser printer and the file server, which are
expensive pieces of hardware. Other equipment or nodes also may be added to
the LAN—for instance, more microcomputers, a mainframe computer, or opticaldisc storage devices. Additionally, the network gateway is a device that allows
one LAN to be linked to other LANs or to larger networks. For example, the LAN
of one office group may be connected to the LAN of another office group.
There are a variety of different standards or ways in which nodes can be
connected to one another and ways in which their communications are controlled in a LAN. The most common standard is known as Ethernet. LANs
using this standard are sometimes referred to as Ethernet LANs

Home Networks 
While LANs have been widely used within organizations for years, they are now
being commonly used by individuals in their homes and apartments. These
LANs, called home networks, allow different computers to share resources,
including a common Internet connection. Computers can be connected in
a variety of ways, including electrical wiring, telephone wiring, and special
cables. One of the simplest ways, however, is without cables, or wireless.

 Wireless LAN 
A wireless local area network is typically referred to as a wireless LAN (WLAN). It
uses radio frequencies to connect computers and other devices. All communications
pass through the network’s centrally located wireless access point or base station.
This access point interprets incoming radio frequencies and routes communications
to the appropriate devices. To see how
home networks work, visit our Web site
at www.computing-2012.com and enter
the keyword network.
To learn more about how to set
up and use a wireless home network,
see Making IT Work for You: Home
Networking on pages 264 and 265.

 Personal Area Network 
A personal area network (PAN) is
a type of wireless network that works
within a very small area—your immediate surroundings. PANs connect cell
phones to headsets, PDAs to other
PDAs, keyboards to cell phones, and
so on. These tiny, self-configuring networks make it possible for all of our
gadgets to interact wirelessly with
each other. The most popular PAN technology is Bluetooth, with a maximum
range of around 30 feet. Virtually all wireless peripheral devices available today