Communication and Networking
Introduction
Communication and networking are changing our life day by
day. The exchange of information between sender and receiver with the help of
electronic means is called Communication. It play important role in our life.
Electronic means may be wire, radio or satellite.
Components of
Communication.
There are five important components of communication of
Communication, which are given below.
1 Message: - Message is the data and information. It may be
text, audio, video, photo etc.
3 Receiver: - The receiver device receive the data or
information from the sender and it can be computer, mobile and any electronic
device.
4 Transmission Medium: - The Transmission is those medium
which is help to transfer the data or information from sender to receiver. It
can be wired or wireless
5:- Protocal: - Protocal is a set or collection of rules
that manage the data communication. It is help to communicated to devices.
Without protocal devices can be connect but not be communication
Networking
Networking is the process of interconnecting of two or more
object. The object may be people, computer, mobile, animal etc. In this world,
there are found various type of networking such as: computer network, human
network, radio network, telephone network etc. Computer network is the
interconnection of two or more network devices with the help of transmission
media and set of rules.
Advantage of
Networking
1:- Resources Share: We can share hardware resources such as
processor, storage devices, printers, scanner etc using computer network.
Similar, software can be shared among us within a network. It is possible to
share data or information among multiple users at the same time.
2:- Faster and Cheaper Communication: we can easily share
data to user from one place to place in low price. It is become very faster and
cheaper to send information to a long distance through network.
Disadvantage of
Networking
1 Expensive: In
the case of installing computer network, we required some more money to
purchase networking devices such as hubs, switch, cables etc. Networking equipment’s and networking
software are too expensive.
2 Security
Problem: - Network security is the most challenging job for network
administrator in order to protect network resources from unauthorized user and
physical destructions. Similarly, the hacker and viruses are the great threat
to the computer in the network.
Signal
In wave technology, there are two signal are mostly use for
data transmission which are analog signal and digital signal.
Analog Signal
Analog
signal is a simple periodic signal that is represented by sine wave. It is used
to represent analog data. The example of analog signal are human voice, radio
signals, television signal, etc.
Advantage
we can
transfer large size of data
It is
suitable for the long range data transmission.
It is cost
effective for the installation and operation of analog data transmission.
Disadvantage
Service
quantity is very poor.
It may
have noise that degrades the quality of signals.
Digital Signal
Digital signal is discrete signal that is represented by
limited number of values such as zero and one. In simple way those type of
signal that has limited number of defined values.
Advantage
It is
effective for short distance data transmission.
It
consists of less amount of noise compare to analog signal.
It is
easy to recover data during transmission.
Disadvantage
It is
more expensive than analog signal.
It is not suitable for long
distance data transmission.
It has
limited capacity for data transmission.
Direction
of communication flow.
There are mainly three type of data communication which are
given below:
Simple
Half Duplex
The flow of data signal in half duplex mode of communication
is bidirectional. Both device can not send and receive at a time. Only one
device can send or receive at a time. Example: walkie-Talkie.
Full Duplex
The flow of data signal in full duplex mode of communication
is bidirectional. Both device can send and receive at a time. Example:
walkie-Talkie. Example: Communication between Telephones, Mobile Phone etc.
Type of Network
The computer network can be classified on the basis of size
and architecture.
On the basis of Architecture
Network architecture refers to services provided by the
network for example, how data transmitted from one to another device, how to
implement and how they are interconnect using protocal. On the basis of architecture
there are two categories: peer to peer network and client server network.
Peer to Peer Network architecture
In peer to peer architecture, every workstation have equal
capabilities and responsibility in network. There are no any server. Message is
send from one computer to another in one to one basis by making peer. For
example: there are three computer in an office. Computer A, B and C. If
Computer A wan to send data to Computer C. The data will send to computer B and
computer B send to computer C.
Figure No.(fig of peer to peer
network)
Advantage
It
is easy to install
It’s
does not need any server
It
is suitable for small area
Disadvantage
It
has maximum 10 nudes
Its
performance become poor for large area.
There
is no central backup and recovery
Client Server Network
In peer to peer architecture, every workstation have not
equal capabilities and responsibility in network. There are two type of
computer one is server and another is client. Server is the main computer in a
network and that control all client computer. Server computer is very high
performance and powerful computer in the network and client computer is normal
computer.
Figure No.(fig of Client Server
Network)
Advantage
It
is suitable for large area
There
is central backup and recovery
It
is easier for controlling and monitoring other computer from server computer
Disadvantage
It is more expensive compare to
peer to peer network.
It
is more complex rather than peer to peer network to install.
If
any problem occurs in the server computer, the entire network will down.
On the basis of
Geographical Area.
On the basis of Geographical Area mean how much area is
covers. This computer network classified into three categories which are given
below
Local Area Network
Local Area Network (LAN) is the private network. It spans
small area such as within a room, building and up to two or Three Kilometers. It
connect the network resources like computer, printer, faxes and other
networking device. User also can share the resources like Data, file software
etc. The most common topology for LAN are bus, ring and star.
Figure No.(fig of LAN)
Metropolitan Area
Network (MAN)
Metropolitan Area Network (MAN) can be public or private
network. The size of MAN is bigger than LAN. It spans within one metropolitan city
(up to 100 kilometer). It can connect large number of computer or multiple LAN.
The most common topology for MAN are mesh and hybrid. It uses different type of
media such as optical fiber cable, coaxial cable, microwave etc.
Figure No.(fig of MAN)
Wide Area Network (WAN)
Wide Area Network (WAN) is a public type of network. It is
the largest size network. It can connect millions of computer, thousands of LAN
and Hundreds of MAN. It used mesh and hybrid topology. It is less secured
network and it has highest error rate. It has low speed of data transfer.
Figure No.(fig of WAN)
LAN Topologies
Network topology refers to the computers in the network and
how they are interconnected to each other. In simple word, network topology
refers to the physical layout of the network. It shows the geometrical
description of all the links and linking devices. The most common LAN
topologies are Bus, Star, Ring, Tree, Mesh and Hybrid.
Bus Topology
Bus Topology is the network setup where computers are
connected to a single continuous cable. A bus runs throughout the office to
which all the computers are connected. It is based on client server network
architecture.
Figure of Bus Topology
Advantages
It is simple and easy to setup.
It does not requires additional network devices.
If any computer in the network downs, then it does not
affect other computers.
It is more flexible than other topology.
Disadvantages
There may be chances of data collision due to data traffic.
If there is a problem in the bus then the entire network goes
down.
It is very difficult to find out the fault.
Star Topology
Star topology is the network setup where computers in the
network are connected to each other with the help of central connecting device
hub, switch, or server. It is based on client server architecture. It is the
most popular and widely used topology for Local Area Network (LAN).
Figure 3.15: Star Topology
Advantages
It is simple, reliable and easy to set up.
It is flexible to connect new computer and remove existing computer
in the network.
It is very easy to find out fault because of the use of a hub
or switch.
Disadvantage
It requires a very large amount of cables.
It is an expensive topology because of cables and networking
device hub or switch.
If there are any issues in the central device hub or switch then
the entire network will be down.
Ring Topology
Ring topology is the network setup where computers are
interconnected to each other by making a closed circular structure. It means
each computer is connected to other two adjacent computers in either side. It
is based on peer-to-peer network architecture.
Figure of Ring
Topology
Advantages
It is a simple and inexpensive topology.
There is less chance of data collision because of unidirectional
data transmission.
There is no server so each computer has equal access
facilities to the resources.
Disadvantages
It is difficult for adding and removing new nodes.
It is not able for large size network.
If there is issues in any computer or connection then the
entire network goes down.
It is very difficult to find out the bug in the network.
Mesh Topology
Mesh topology is the network setup where every computer has
point to connection to all other computer by using multi-port connecter. There
are multiple connections between two computers which provide the alternate
paths for data transfer. It is also based on peer to peer architecture.
Figure 3. 17: Mesh
Topology
Advantages
It is the fastest and robust type of topology.
It is considered as the most reliable topology because of
multiple connections between any two nodes.
Failure in any computer or transmission media does not
affect the rest of the network.
Disadvantages
It is very much complex and costly topology.
It is difficult to find an error in the network.
It requires maximum amount of cables and multiport connecters.
It is difficult to add and remove nodes in the network so it
is not flexible.
Tree Topology
Tree topology is the extension of bus or star topology. So
it extends the branches of bus or star topology allowing more stations to
access the bus. As shown in the figure, the computers are arranged in a
distinct hierarchical structure. Data can flow from top to bottom vice versa. A
break in the bus is very difficult to locate.
Figure 3.18: Tree
Topology
Advantages
It is easy to manage network as per our needs because of
many sub networks or units.
It is very flexible so we can add and remove any number of
nodes.
It is easier to find the fault nodes or hubs in the network.
It makes easier to isolate and assign priorities into
different level of units.
Disadvantages
The failure of root node will cause the failure of entire
network.
It is expensive because of large amount of cables and
network devices- hubs or switch.
The data traffic is high at root node so there may be
chances of data collision.
Hybrid Topology
If two or more topologies are combined together then it is called
hybrid topology. So it is very difficult to design and to implement the hybrid topology.
It is expensive too. Because we need to install additional the network devices such
as router or gateway.
Figure 3.19: Tree
Topology
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