Let's say you're in
charge of setting up a computer network for an office building. Every desk has
a computer on it, and there are also some printers and other peripheral devices
sitting around. What are you going to need in terms of hardware to set up the
network? You probably guessed that you're going to need some cables, but what
else? Time to sit down and make a shopping list before you head out to the
computer store.
Transmission Media
The first thing to
consider is how you plan to transmit data across the network. The transmission
media of a computer network describes the material substances that
carry energy waves, which include the data being transferred. The two main
categories are wired, or guided, which uses physical cables, and wireless, or
unguided, which uses electromagnetic waves that can travel through a vacuum or
a medium, such as air. Wireless signals do not require a physical medium, such
as cables.
The most commonly used
wired connections use twisted-pair cables, coaxial cables and fiber optic
cables. Twisted-pair cables consist of individual copper wires that are twisted
into pairs. The wires are wrapped in an insulation material. Twisted-pair
cables are widely used for telephone service.
A coaxial cable
consists of a copper or aluminum wire wrapped inside an insulating layer. Most
cable TV companies use coaxial cables. A fiber optic cable consists of a
central fiberglass core surrounded by several layers of protective material.
This type of cable transmits light rather than electronic signals. A light
emitting diode (LED) or laser is used to create the light pulses. The
transmission speed of a fiber optic cable is much faster compared to the other
cables. Most networks built today use a fiber optic cable because of its
superior speed, but coaxial cable is also very common.
The most commonly used
wireless connections use radio waves, microwaves and infrared waves. You
obviously don't need cables for a wireless connection, but you will need other
hardware for the transmission of wireless signals through the air.
Repeaters, Hubs,
Bridges and Switches
A repeater is
a device that receives electronic signals, cleans them and retransmits them at
a higher power level. Signals transmitted over cable tend to degrade over long
distances. Repeaters are needed so that the signal can travel longer distances.
A hub is
a networking device used to connect multiple devices directly to the network
using cables. Each connection is called a 'port.' The connections typically
consist of a fiber optic Ethernet cable. When the hub receives data at one of
its ports, it distributes the data to the other ports in the network.
Typically, a hub sends all the data it receives to all the other ports.
Switches contain many ports to connect different
network segments. They are similar to hubs, but offer greater performance. When
a network contains a large number of devices, switches are needed instead of
hubs to make sure the communications between devices does not slow down.
Contrary to hubs, switches send the data it receives only to specific ports.
Bridges are networking devices that divide up
the network into different segments to manage the amount of traffic. This
prevents unnecessary traffic from entering other parts of the network and
reduces congestion. As a network becomes more complex, bridges make sure your
network speed doesn't drop dramatically.
Consider for a moment
all the different communications that take place in an organization. Some
communications are face to face, but others use some type of technology. Think
of email, phone calls, text messaging, viewing pages on the Internet,
downloading files. All of these communications make use of a telecommunications
system. A telecommunications system is a collection of nodes and links to
enable telecommunication. Telecommunication is communication at a distance
using electrical signals or electromagnetic waves.
Examples of
telecommunications systems are the telephone network, the radio broadcasting
system, computer networks and the Internet. The nodes in the system are the
devices we use to communicate with, such as a telephone or a computer.
Components of a
Telecommunication System
In its most
fundamental form, a telecommunication system includes a transmitter to take
information and convert it to a signal, a transmission medium to carry the
signal and a receiver to take the signal and convert it back into usable
information. This applies to any communication system, whether it uses
computers or not.
Most modern day
telecommunications systems are best described in terms of a network. This
includes the basic elements listed above but also the infrastructure and
controls needed to support the system. There are six basic components to a
telecommunications network.
1. Input and output
devices, also referred to as 'terminals'
These provide the
starting and stopping points of all communication. A telephone is an example of
a terminal. In computer networks, these devices are commonly referred to as
'nodes' and consist of computer and peripheral devices.
2. Telecommunication
channels, which transmit and receive data
This includes various types
of cables and wireless radio frequencies.
3. Telecommunication
processors, which provide a number of control and support functions
For example, in many
systems, data needs to be converted from analog to digital and back.
4. Control software,
which is responsible for controlling the functionality and activities of the
network
5. Messages represent
the actual data that is being transmitted
In the case of a
telephone network, the messages would consist of audio as well as data.
6. Protocols specify
how each type of telecommunication systems handle the messages
For example, GSM and
3G are protocols for mobile phone communications, and TCP/IP is a protocol for
communications over the Internet.
While early
telecommunication systems were built without computers, almost all systems we
use today are computerized in some way.
Computer Network
A computer
network is a system of computers and peripheral devices that are
connected electronically. These connected computers can communicate with each
other, which means that they can share information. Each computer has its own
network address, so it can be uniquely identified among all the computers in a
network. Computer networks are able to carry different types of data and
support different applications.
Computers are
connected using a number of different types of communication channels. These
include both wired and wireless connections. Wired connections consist of an
actual physical cable, such as copper wire or fiber optics. Wireless connections
do not use a physical cable but transfer data using waves at a particular part
of the electromagnetic spectrum.
Today we’re taking a look at the home networking hardware: what
the individual pieces do, when you need them, and how best to deploy them. Read
on to get a clearer picture of what you need to optimize your home network.
When do you need a switch? A hub? What exactly does a router do?
Do you need a router if you have a single computer? Network technology can be
quite an arcane area of study but armed with the right terms and a general
overview of how devices function on your home network you can deploy your
network with confidence.
Why do we need a
computer network? Transferring files between individual computers can be
accomplished using physical media, such as DVDs or external hard drives, but a
computer network makes it possible to transfer data between computers without
having to use physical media. So if you are looking to buy computer networking
products visit Allindiayellowpage.com to find computer networking products available stores in your
city.