Introduction to Computer Networks

The network can be defined as the set of groups or organizations where different ideas and information can be shared. In the context of computers, a computer network can be defined as the set of groups of multiple computers connect to share data, files, hardware, application, information, and many other purposes. To understand the network between computers, we must first understand networking principles. These fundamental principles enable users to share their ideas and experiences with others about computer networks. A network must adhere to some network protocols in addition to the principles.

Introduction
The network can be defined as the set of groups or organizations where different ideas and
information can be shared. In the context of computers, a computer network can be defined as
the set of groups of multiple computers connect to share data, files, hardware, application,
information, and many other purposes. For the communication or sharing of these data,
computers should be connected to a network. For the connection of the computer’s different
types of wire or wireless devices are used. To understand the network among the computers
we need to know networking principles. Those main principles help user to deliver their ideas
and experience about the computer network with others. Along with the principles, a network
must follow some network protocols. Therefore, Network protocols are the set of policies and
plans, which contains some formats and rules for making possible communication between
computers over a network. Similarly, Networking devices are also required, Networking devices
are those physical devices, which are required communication and interaction between
hardware on a computer network. These networking devices connect various networks using
different types of networking protocols. Similarly, the Network topology is the process of
arranging elements present in a communication network that can be depicted physically or
logically.
Fig no.1: computer network
Source: https://1.bp.blogspot.com/-FBc_Q-tj2oA/XoIBk69CkKI/AAAAAAAAAnk/5P7PVJHTc0MQSzhA-dQGNh9gXuROmk6pwCLcBGAsYHQ/w1200-h630-p-k-no-
nu/Pengertian-Komunikasi-Daring.jpg
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 Advantage of a computer network:
 It helps to share an internet connection. Using a home network or office, multiple devices
can be connected to access the internet without having to pay for an ISP for multiple
accounts.
 Devices like network printers, scanners, webcams, and CD burners can be shared.
 Files like audio, photos, videos, text can be shared.
 Multiple online and popular games can be played with different people from different
places at the same time.
 Storage capacity also can be increased.
Having the better advantage of computer networks there is some limitation of computer
networks.
 Limitations of computer network
 The major drawback of computer networks is security issues. If a computer is on a
network, computer hackers can get unauthorized access by using different tools.
 The rapid spread of computer viruses. Viruses get spread on a network easily because of
the interconnection of the workstation. Viruses make our computer slow, can also delete
important files.
 Network faults can cause loss of data.
 Purchasing the network cabling and file servers can be expensive.
 Managing a large network is complicated, requires training and a network manager
usually needs to be employed.
These are the advantages and disadvantages of computer networks. As we know there are
different types of computer networks. So, the different types of computer networks there use,
advantages, and disadvantages are now discussed below.
Types of computer networks are:
i. PAN (Personal Area Network)
ii. LAN (local area network)
iii. MAN (metropolitan area network)
iv. WAN (wide area network)
v. WLAN (wireless local area network)
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Fig no.2: Types of computer networks
PAN (Personal Area Network)
PAN stands for personal area network. A personal area network, or PAN, is a computer network
organized around a person within a single building. This could be inside a small office or
residence. A typical PAN would include one or more computers, telephones, peripheral devices,
video game consoles, and other personal entertainment devices.
If multiple individuals use the same network within a residence. In a very typical setup, a
residence will have a single wired Internet connection connected to a modem. This modem then
provides both wired and wireless connections for multiple devices. The network is typically
managed from a single computer but can be accessed from any device.
This type of network provides great flexibility. For example, it allows us to:
 Send a document to the printer in the office upstairs while we are sitting on the couch
with our laptop.
 Upload a photo from your cell phone to our desktop computer.
 Watch movies from an online streaming service to our TV.
A personal area network (PAN) is the interconnection of information technology devices
within the range of a person, typically within a range of 10 meters.
Fig no.3: PAN (personal area network)
Source: https://1.bp.blogspot.com/KPfhVqSWkAg/V6X0P5B1twI/AAAAAAAAARI/9qNGNlJ_FsEeSTL1U8GMyIeYW8Gsp7twQCLcB/s1600/pan.jpg
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The main characteristics of PAN:
 It is mostly personal devices network equipped within a limited area.
 Allows you to handle the interconnection of IT devices in the surrounding of a single
user.
 PAN includes mobile devices, tablets, and laptops.
 It can be wirelessly connected to the internet called WPAN.
 Appliances used for PAN: cordless mice, keyboards, and Bluetooth systems.
Benefits of PAN network:
 PAN networks are relatively secure and safe
 It offers only short-range solutions up to ten meters
 Strictly restricted to a small area
The drawback of using PAN network:
 It may establish a bad connection to other networks at the same radio bands.
 Distance limits.
LAN (Local Area Network):
• A local area network is a network, which is used in local areas means it is a small
network that covers small areas like an office, school, college, building, etc. In this
network, we can connect computers, printers, servers, and other network devices.
Local area network is a privately owned network that means anyone can create this
network easily we just need some cables like Ethernet cables or central devices like
hub or switch. Local area networks are capable to transfer data at very fast rates so
data transfer speed over a LAN network can reach up to 1000 Mbps. Using Ethernet
cables, data transfer speed can reach up to 10 Mbps and by using FDDI or Gigabit
Ethernet, data transfer speed can reach up to 1 Gbps. The Range of LAN is 1000
meters.
Uses of Local Area Network:
 LAN networks are mostly used in businesses where all business data is stored in servers.
 This network can be used in factories.
 This network can be used in Schools and Colleges where all the students, teachers, and
staff data are stored in servers.
 This network can also be used in our homes where all the computers, mobiles, printers
are connected to the switch/router, and these devices can exchange data.
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Now, here are the important characteristics of a LAN network:
 It is a private network, so an outside regulatory body never controls it.
 LAN operates at a relatively higher speed compared to other WAN systems.
 There are various kinds of media access control methods like token ring and ethernet.
Benefits of LAN:
 Computer resources like hard-disks, DVD-ROM, and printers can share local area
networks. This significantly reduces the cost of hardware purchases.
 You can use the same software over the network instead of purchasing the licensed
software for each client in the network.
 Data of all network users can be stored on a single hard disk of the server computer.
 You can easily transfer data and messages over networked computers.
 It will be easy to manage data in only one place, which makes data more secure.
 Local Area Network offers the facility to share a single internet connection among all the
LAN users.
Drawbacks of LAN:
 LAN will indeed save cost because of shared computer resources, but the initial cost of
installing Local Area Networks is quite high.
 The LAN admin can check the personal data files of every LAN user, so it does not offer
good privacy.
 Unauthorized users can access critical data of an organization in case LAN admin is not
able to secure a centralized data repository.
 Local Area Network requires a constant LAN administration as there are issues related to
software setup and hardware failures.
Fig no.4: Local Area Network (LAN)
Sources: http://4.bp.blogspot.com/-xZM7NSPBaBM/T_sO-DTRiAI/AAAAAAAAAAc/WhqTfq2c_Bk/s1600/Local-Area-Network.jpg
MAN (Metropolitan area network)
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MAN stands for metropolitan area network. It is a large computer network that usually spans a
vast geographical area and is used in large companies and university campuses. For example,
MAN is used to link the various buildings such as academic colleges or departments, libraries,
student residence halls, etc. located within a university campus. A Metropolitan Area Network
(MAN) is a large computer network on a large geographical area that includes several buildings
or even the entire city (metropolis). The geographical area of the MAN is larger than LAN but
smaller than WAN. MAN includes many communication devices and provides Internet
connectivity for the LANs in the metropolitan area.
MAN is used to combine into a networking group located in different buildings into a single
network. The diameter of such a network can range from 5 to 50 kilometers. MANs rarely extend
beyond 100 KM and frequently comprise a combination of different hardware and transmission
media.
Now, here are important characteristics of the MAN network:
 It mostly covers towns and cities in a maximum 50 km range
 Mostly used medium is optical fibers, cables
 Data rates adequate for distributed computing applications.
Benefits of MAN network:
 It offers fast communication using high-speed carriers,
like fiber optic cable.
 It provides excellent support for an extensive size network and
greater access to WANs.
 The dual bus in the MAN network provides support to transmit
data in both directions concurrently.
 A MAN network mostly includes some areas of a city or an
entire city.
Drawbacks using the MAN network:
 You need more cable to establish a MAN connection from one
place to another.
 In MAN network it is tough to make the system secure from
hackers.
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Fig no.5: MAN (Metropolitan Area Network)
Source: https://4.bp.blogspot.com/RrRe9jtXpw8/XMse7IpOyoI/AAAAAAAAAvU/g8zIba_ucMYJ1XNvWkkJjauEjiRv5sZrQCLcBGAs/s1600/metropolitan%2Barea%2Bnetwork.png
WAN (Wide Area Network):
WAN stands for Wide Area Network. A WAN is a network that spans more than one
geographical location often connecting separated LANs. WANs are slower than LANs and often
require additional and costly hardware such as routers, dedicated leased lines, and complicated
implementation procedures. Wide area networks are implemented to connect a large number of
LANs and MANs. Due to this reason, it is possible to see a large number of heterogeneous
components in a wide area network. Different communication media are used, and the network
spreads across several national boundaries. Computers connected to a WAN are often connected
to a public network. They can also be connected through leased lines or satellite links. The
government or large concerns mostly use WAN because of the considerable investment made to
implement them.
Now, here are the characteristics of WAN:
 The software files will be shared among all the users;
therefore, all can access the latest files.
 Any organization can form its global integrated network using
WAN.
The benefits of WAN:
 WAN helps you to cover a larger geographical area. Therefore,
business offices situated at longer distances can easily
communicate.
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 Contains devices like mobile phones, laptops, tablets,
computers, gaming consoles, etc.
 WLAN connections work using radio transmitters and receivers
built into client devices.
The drawbacks of the WAN network:
 The initial setup cost of investment is very high.
 It is difficult to maintain the WAN network. You need skilled
technicians and network administrators.
 There are more errors and issues because of the wide
coverage and the use of different technologies.
 It requires more time to resolve issues because of the
involvement of multiple wired and wireless technologies.
 Offers lower security compared to other types of networks in
computers.
Fig no.6: WAN (Wide Area Network)
Source: https://www.classmate4u.com/wp-content/uploads/2020/04/WAN.gif
WLAN (wireless local area network):
WLAN stands for wireless local area network. It is a wireless connection that connects two or
more devices in LAN. WLAN uses access points and routers to make a connection between
devices. Wi-Fi is an example of WLAN where devices are connected wirelessly within a limited
range. WLAN is made within home, office building, computer laboratory, school building, or
any college campus. For using Wi-Fi, users need to enter a password for making a connection to
the internet. Wi-Fi connection is made either by using mobile hotspots or by using a wireless
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modem or wireless router. WLAN includes an access point (AP) which is used to connect to the
internet. AP sends and receives radio frequency signals to the connected devices. In 1990 WLAN
installation was expensive and was only deployed where the wired connection was not possible.
In the late 1990s, cost decreases to implement WLAN because of using IEEE 802.11 standard. It
works with a bandwidth of 2.4 GHZ (802.11b) or 5 GHZ (802.11 a). The devices which WLAN
connects are also called clients.
Advantages of WLAN:
 It is a reliable type of communication.
 As WLAN reduces physical wires it is a flexible way of communication.
 WLAN also reduces the cost of ownership.
 It is easier to add remote workstations.
 It provides a high data rate due to small area coverage.
 You can also move the workstation while maintaining the connectivity.
 For propagation, light of sight is not required.
 The direction of connectivity can be anywhere i.e., you can connect devices in any
direction unless it is within the range of the access point.
 Easy installation and you need don’t need extra cables for installation.
 WLAN can be useful in disasters situation e.g., earthquakes and fires. People can still
communicate through the wireless network during a disaster.
 It is economical because of the small area access.
 If there are any buildings or trees then still wireless connection works.
Disadvantages of WLAN:
 WLAN requires a license
 It has a limited area to cover
 Government agencies can limit the signals of WLAN if required. This can affect data
transfer from connected devices to the internet
 If the number of connected devices increases then the data transfer rate decreases
 WLAN uses radio frequency which can interfere with other devices which use radio
frequency
 If there is rain or thunder then communication may interfere
 Attackers can get access to the transmitted data because wireless LAN has low data
security
 Signals may be affected by the environment as compared to using fiber optics
 The radiation of WLAN can be harmful to the environment
 As WLAN uses access points are more expensive than wires and hubs
 Access points can get signals of nearest access points
 It is required to change the network card and access point when standard changes
 LAN cable is still required which acts as the backbone of the WLAN
 Low data transfer rate than wired connection because WLAN uses radio frequency
 Chances of errors are high
 Communication is not secure and can be accessed by unauthorized users
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Fig no.7: WLAN (Wireless Local Area Network)
Source: http://accoladewireless.com/wp-content/uploads/2015/05/wlan41.jpg
These are the different types of networks, now we are going to discuss the different network
systems, their advantages, and disadvantages. So, the different types of the network system are:
I. Peer-To-Peer Network
II. Client-Server Network
III. Cloud Network
IV. Cluster Network
V. Virtualized Network
VI. Centralized Network
I. Peer-To-Peer Network:
A Peer-to-Peer network is defined as a network of computers, which does not consist server and
is mostly used by small organizations, which allows sharing of certain files and folders to every
user or selected user. Small organizations, having peer-to-peer networks uses a dedicated file
server. In such networks, files and folders can only be configured to allow the users for copying
them. Those files and folders cannot be placed/altered in their original location. This is done for
the safety of files and folders. Characteristics of a Peer-to-peer network are similar to small local
area networks (LAN). Computers involved in a peer-to-peer network use the same set of
networking rules and regulations and the same software. The router provides centralized Internet.
In these types of networks, computers are connected directly. This kind of network is mostly
used in small organizations like schools, colleges, and small government offices where there is
no need for security. It is mostly used for sharing data and information.
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Fig no.8: Peer-To-Peer Network
Source: https://th.bing.com/th/id/R.e5b30376cbdb01c1b8a9714050109b91?rik=ivjgFC6ATT8jbQ&riu=http%3a%2f%2f2.bp.blogspot.com%2f-5HkiC8bwPWU
%2fUal0MvjajyI%2fAAAAAAAAEpo%2fpT6-xz6ksRY%2fs1600%2fpeer_to_peer.jpg&ehk=8%2bUDxmP%2fYAE6QYr0FixCjD5HeUywFfbeXpUzeCGEp9w
%3d&risl=&pid=ImgRaw&r=0
 Benefits of peer-to-peer network:
I. Easy to set up and manage.
II. Less chance of hacking and cracking.
III. No requirement of skilled manpower.
The first benefit of a Peer-to-Peer Network is that the computers can be easily be configured in
their workgroups allowing the sharing of files, printers, and other resources across all the
devices. The data and information can be shared in both directions in such networks. Those data
and information can be downloaded to the computer and can be uploaded from the computer.
The Peer-to-Peer network is cheap compared to other networks. Configuration and
implementation of the peer-to-peer network can be easily done in less time. The next important
feature of such a network is that it is responsible to distribute load across many computers.
A peer-to-peer network helps to share the files having a high volume from one computer to
another. They are more resilient than client-server networks whenever a failure occurs. Peer-to-
Peer network is easier to set up and install. P2P has the advantage that if one peer does not work
properly or faces failure then also it does not affect the functioning of other peers. That is why it
is very reliable. The network does not get affected even though the server goes down. There is no
specific network administrator in such networks. Users can control the resources that they have
shared.
 Constraint of peer-to-peer network:
I. Not suitable for the large organization but can be best for small organizations.
II. Less security but chances of hacking and cracking is low.
III. Cannot be managed centrally.
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As a peer-to-peer network does not rely on a central server and it does not have a specific
administrator, the whole system is decentralized and it is difficult to control. In such networks, a
specific person cannot have the right to determine the whole accessibility setting of the network
to handle it properly. One of the main drawbacks is that it is not secure. Security is very poor
because of which viruses and malware can easily be transmitted over its architecture. Once the
data gets lost from this type of network, it cannot be recovered, or even if it is recovered, it takes
a lot of time and hard work. A computer in this network must have a backup system. A peer-to-
peer network is a technology, which is mostly used in torrents. In torrents, it is used to transfer a
lot of movies, music, and other copyrighted files. It slows down the performance of users
because others or anyone in this network can access each computer.
II. Client-Server Network:
Client-server Network is the complex type of network containing a server that is mostly used by
many large organizations such as banks, telecom, etc. In a client-server network, the client
computer must request a service with the server program of another computer before accessing
the data of that computer. If the server computer accepts the request, then only the client
computer can continue its further processes in the computer. It is an important idea in a network.
In a network, the client/server computer is responsible to provide a convenient way of
interconnecting the programs. A client-server network is one of the central ideas of computing. It
is very beneficial for business purposes so, most of the business applications are performed using
this type of network. Both client programs and server programs of this network are usually a part
of a larger application.
For example, on the internet, a web browser acts as a client computer that sends requests to a
Web server in another computer located somewhere on that internet. In this type of network, one
server supports many clients. Multiple servers can also be networked together in a pool to handle
the increasing number of clients if required. This type of network can differentiate between
devices and applications. Here, a device that acts as a server for one application simultaneously
acts as a client to other servers for different applications. In this network, all computers are
connected to a powerful computer for data sharing and data use. It is a centralized network that is
more secured and advanced than a peer-to-peer network.
Fig no.8: Client-Server Network
source: https://www.itrelease.com/wp-content/uploads/2021/05/Client-server-network-1.jpg
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 Benefits of client-server:
I. Centralized network.
II. High security comparatively to the peer-to-peer network.
III. More efficient access to network resources.
In this type of server, there is centralized control. Servers administer the whole setup of the
network. The server is responsible to give access and rights to the client’s computer. It also
allocates the resources of the computers. Servers play different roles for different clients. This
type of server consists of a proper management system because of which all the files are stored at
the same place. This makes the management of files easy and it is easier to find files as well. If
any data and information are removed then they can easily be stored in this network because the
data are stored in the server and it is very easy to get a backup of files and folders from the
server. There are many benefits of having a client-server network. Changes can be easily made
in this network. Only the thing that needs to be done is to upgrade the server. After upgrading it,
new resources and systems can also be added.
The client-server network is very accessible. The servers can be easily accessed from any
platform present in the network. There is not a necessity for each computer to increase its storage
at every workstation like in a Peer-to-peer network because the new ideas and information itself
are stored and uploaded in the server. The changes are made only on the centralized computer so
that it does not affect the files and folders of another computer. It is a very secure type of
network.
 Constraint of client-server:
i. Server failure leads to whole network failure.
ii. Complex type of network but it is centralized.
iii. Required skilled manpower and costly.
Although it is a very advanced, type of network and has great importance in the case of
networking, there are some of its demerits. As this network is very secure and beneficial, many
requests may come from the clients, which overloads the server by leading to congestion. This
may lead to a server breakdown. The server is the main component of the whole client-server
network so, if a server fails then there is a chance of breakdown of the whole network. The
whole network depends upon the server as it handles all the activities. After the server fails, it is
impossible to get any broken parts of the file also. There is a great risk of system overloading. If
the server breaks down then it is very costly to fix it. If the server breaks down then it requires
professional IT people to maintain it. Only an IT professional can also manage all the technical
details of the network.
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A regular staff also cannot provide service to even some of the customers because to meet the
work, at first, it requires specific software and hardware, which needs to be granted by the server
only. The client does not contain many of the resources that are present on the server. In case of
damage to the server, only a specialist can fix it. According to its development and various
advantages, it is worth the cost but from another side, it cannot be afforded by all the
ewrdsforganizations and only for the software and hardware, it costs a lot, which is a constraint.
This type of network is difficult to manage as well.
III. Cloud Network:
Cloud networking is defined as the computer network which describes the access of networking
resources from a centralized third-party provider by providing network interconnectivity between
cloud-enabled services using Wide Area Networking (WAN) or Internet-based access
technologies. It is responsible to share computing resources between the clients from the
centralized server. Both network and computing resources can be shared in cloud networking.
Most of the network management functions are sent into the cloud to be able in using only fewer
customer devices for managing the network. Cloud networks enable network communication
between virtual machines. To sum up, it is a widely practiced network as remote access is
possible because of it and anyone can access this network easily as the resources are centralized.
Cloud computing is a computing paradigm, where a large pool of systems is connected in private
or public networks, to provide dynamically scalable infrastructure for application, data, and file
storage. With the advent of this technology, the cost of computation, application hosting, content
storage, and delivery is reduced significantly. There are three types of cloud which are private,
public, and hybrid. It is a practical approach to experience direct cost benefits and it has the
potential to transform a data center from a capital-intensive set up to a variable priced
environment.
Fig no. 11: Cloud Network
Source: https://www.sys.com.tr/wp-content/uploads/2017/03/cloud-computing-annymo-soft-600x447.png
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 Benefits of cloud computing:
i. Reduced cost.
ii. Increased storage.
iii. Flexibility
Cloud computing enables the user to deploy the service just in fewer clicks. The resources
required for the system can also be gained quickly within fewer minutes. The data and
information stored in the cloud can be accessed anywhere and at any time. Therefore, it helps to
avoid delays in the work of the company. It is also easy to get them back- up and recover the
data from the cloud network. This helps in saving our time to perform and complete other
activities. Without cloud computing, it is not possible to run any business in a more reliable and
manageable way. Cloud computing also helps in focusing on keeping up or being updated about
the business competition by offering access to the most trending and in-demand applications.
Cloud network helps the users to perform all the manual work of installing and maintaining the
applications that they require. Cloud computing is an emerging technology in which almost
every company switches for better performance in the company. Cloud computing is a necessity
for every company to rise to the business competition. The biggest reason for a company to
switch their technology with cloud computing technology is that it is considerably cheap than on-
premise technology. Enabling cloud computing in the companies maintains enormous storage
space to store the resources, which directly helps to save the money of the company as the
company. Cloud computing is also responsible to manage the server by eliminating the need for
IT infrastructure updates and maintenance. It takes care of all the maintenance and management
of IT services.
 Constraint of cloud computing:
i. Data replication
ii. Vulnerability to attack
iii. Downtime problem. So, security should be made a core aspect of all IT operations.
The constraint that cloud computing holds is that it does not have a proper security system
because of which there is a chance of loss of data and information in such a network. The server
can crash easily and at any time, which may cause huge losses to the company. The clients
working with a server containing cloud computing may be stuck in many difficult situations. As
cloud infrastructure is entirely owned and managed by the service provider, the clients have only
limited control over the cloud services and the company cannot have the level of control as they
want over its back-end infrastructure. This does not let the clients be updated about all the data
and information of the company.
The data that gets stored in the cloud is all online-based which is a great risk for a company
because it can be easily hacked or theft by hackers. Thus, it is a serious challenge for a company
to share data through cloud networking. Thus, Cloud computing completely depends on the
internet so, the company must be able to maintain good connection speed and bandwidth for the
business to run it properly and it is also a quite risky decision for a company to store all the data
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through the internet. Therefore, though advanced security measures are deployed on the cloud,
storing confidential data in the cloud is quite risky. There is also the chance of loss of power, low
internet connectivity, etc. in such networks. The server of the company may face various
technical problems or issues because of the cloud networking.
IV. Cluster Network:
Cluster computing can be described as a fusion of the fields of parallel, high-performance,
distributed, and high-availability computing. Clustering involves establishing a connection
between two or more computers to make them appear as a single resource. There’s a complexity
in doing so that typically requires additional costs. Maintenance and monitoring can be
challenging as well. Cluster computing has become a hot topic of research among the academic
and industry community including system designers, network developers, language designers,
standardizing forums, algorithm developers, graduate students, and faculties.
A computer cluster consisting of a set of loosely or tightly connected computers that work
together to be viewed as a single system in different situations is called a cluster network. This
network enables the high availability of a group of servers and resources. A cluster network
integrates the resources of two or more computing devices to work for a certain common
purpose. A cluster computer network is linked through LAN, which makes it more powerful.
This single-core technology or network with multiple computers enables high performance,
larger storage, better data, and wider resources availability. Cluster network computer consists of
each node set to perform the same tasks, which are controlled and scheduled by software. Many
of the companies use cluster networks broadly in computer networking. It helps a user to be able
in referring to several different implementations of shared computing resources.
Fig no.12: Cluster Network
Source: https://th.bing.com/th/id/R.ba5d35560fbdacc650c018ae5fe193c7?rik=lMeQjokc78SIcg&riu=http%3a%2f%2fwww.techyv.com%2fsites%2fdefault%2fusers%2fImages-
Folder%2fcluster-computing-300x208.jpg&ehk=U1BU8TyBXkwoikuJQj%2btmhFyvvMLhUMUa9S2%2bq3HJiM%3d&risl=&pid=ImgRaw&r=0&sres=1&sresct=1
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 Benefits of cluster computing:
i. Clustering servers is completely a scalable alternative. You can add resources to the
cluster afterward.
ii. If a server in the cluster needs maintenance, you can do it by stopping it while handing
the load over to other servers.
iii. It is reliable and easy to configure.
Installing a cluster network is beneficial because the cluster techniques are much cheaper than
installing a mainframe on a server. In a cluster network, multiple computers having high-speed
work together so, it can provide higher processing speed to a server of the company. As,
multiple server computers work together, in case of default or error in one server, the other
server from the cluster takes over the server having an issue handling the situation or a load.
Therefore, a server from the cluster can stop working anytime whenever it requires maintenance.
This behavior of cluster networks ensures the high availability of web applications. It aims of
providing unified processing to the system. The cluster network is flexible because the users can
add an extra component to the system and upgrade itself easily. Resources are added to the
clusters accordingly. The server is designed under a cluster network is for the high availability of
solutions. The servers that are clustered can be configured and managed easily without any
trouble. To sum up, a cluster network is very reliable and easy to configure.
 Constraint of cluster computing:
i. Cost is expensive. Since the cluster needs good hardware and a design, it will be costly
compared to a non-clustered server management design. Being not cost-effective is the
main disadvantage of this particular design but it is a complete server solution.
ii. Since clustering needs more servers and hardware to establish one, monitoring and
maintenance are hard.
Apart from the benefits of this network, it also has some constraints. As multiple computers are
connected in such a network, it requires more servers and hardware to manage and monitor. This
directly increases the infrastructure in the system. This network design does not support many of
the applications. As it does not support most of the applications, it needs to be designed in a
proper way that may cost quite a lot. Since the cluster needs good hardware and a design, it is
costly compared to a non-clustered server management design. Usually, some web-hosting
providers can only afford it. The cluster network is flexible but not as much as it needs to be
because this network can cluster not every server type.
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V. Virtualized Network:
Network virtualization or virtualized network is defined as the method of combining the
available resources in a network to consolidate multiple physical networks. These are networks
are mostly used in large and rapid networks. It is responsible to divide a network into segments
or creating software networks between virtual machines. IT company manages network
virtualization to administrate their environment as a single software-based network and to
optimize network speed, reliability, flexibility, scalability, and security of the system. The
network that faces sudden and large defaults and errors can especially use this kind of network
because it can create a logical software-based view of the hardware and software networking
resources. The network resources are easy to manage and deploy by using the virtual servers,
therefore it is different from the physical networking devices, which simply forward the data
packets. Virtualized networks can align the network to better support virtualized environments.
Network virtualization improves network efficiency and satisfies the administrator with their job.
Virtualization occurs when a virtual version of something is created instead of an actual version.
With modern virtualization, this could contain storage devices, networks, operating systems, or
even servers. It has expanded into almost every form of digital life. From virtual machines that
act like real computers to console emulation, many people take advantage of what virtualization
can provide.
Fig no.13: Virtual Network
Source: https://cdn.b12.io/client_media/1Aiw8cc2/f9ddabfc-10e2-11ea-8115-0242ac110003-diagram.png
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 Benefits of virtualized computing:
i. Cheaper computing.
ii. Reduces the workload.
iii. Provides energy savings.
iv. Promotes digital entrepreneurship.
The first benefit of installing a virtualized network is that it reduces the physical devices in the
system because which network can be easily segmented. As it reduces the physical devices from
the system, no destruction will occur within the system; therefore, this network maintains proper
security in the system. Virtualized networks can immediately increase network efficiency. Thus,
it is relatively easy to organize compared to other network types. Moreover, Virtualization can
recover the files and folders in a much swifter and more accurate way, and for this; it does not
even require more manpower. Using a virtualization server does not require actual hardware
components to be used or installed which makes it very cheaper to use. The activities can be
carried out without worrying about the need for large areas of space and huge monetary
investments to create an on-site resource. The only thing that this network requires is a license
that the user can either purchase or access from a third-party provider and can start working.
This network is the best way to determine or predict the costs required for the information
technology needs of a company. It reduces the workload by automatically updating the hardware
and software using the third-party provider. Thus, this helps the user to focus on other important
tasks of the company by saving their time from installing hardware and software. The network
even saves them money for individuals or corporations. A virtualization network can be called an
energy-efficient system because there are no local hardware or software options that need to be
utilized by the network, which directly lowers the energy consumption rates.
 Constraint of virtualized computing
i. Creates a security risk.
ii. Implementation can have a high cost but it includes storage devices and operating
systems.
Installing a virtualized network can turn into a demerit along with the transition in the
technology. The network can either be purchased or accessed from a third-party provider. As it
cost a high amount to purchase, most of the users access it from the third-party provider but
accessing it from the party provider does not last for a very long time. The license expires and it
needs to be reactivated which is quite a difficult and time taking process for all the management.
When virtualization is being considered, the cost for the average individual or business is quite
low but for the providers of a virtualization environment, the implementation costs can be quite
high. Similarly, it has some limitations because of which only some server works within its
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environment.
Therefore, an individual or company requires a hybrid system to function properly.
The system can still save time and money in the long run, but because some vendor stops
supporting the network after initially starting it, there is always a level of uncertainty while fully
implementing this type of network system. This network also has some security problems. As the
information of a company is very important for it to reach success, it is quite risky to share data
and information using this type of network because hackers can mostly target it. There may also
occur the availability issue of resources or assets in the network. There is a chance that a
company can face the problem of not being able to connect to their data for an extended period.
Therefore, this causes the company to struggle in competing with other companies in the
business industry. In addition, as all the availability chances are controlled by third-party
providers, there is no control over anyone to stay connected.
VI. Centralized Network:
A type of network where all users connect to a central server, which is the acting agent for all
communications. This server would store both the communications and the user account
information. Most public instant messaging platforms use a centralized network. Also
called centralized server structure. “A type of network where all users connect to a central server,
which is the acting agent for all communications. This server would store both the
communications and the user’s account information. Most public instant messaging platforms
use a centralized network” (webopedia, n.d.). The focus of this network is to control, for
example, managing effectively the speed of the network, setting a policy for customers,
flexibility, and reorganization of the network. A centralized network implies a central focus of
control. In other words, the focus of a centralized network is control. For example, through
effective management, a centralized network can control speed, customer service, flexibility, and
reorganization within the network. While centralization does have benefits, this type of network
also poses several significant disadvantages. Centralized computing is a type of computing
architecture where all or most of the processing/computing is performed on a central server.
Centralized computing enables the deployment of all of a central server's computing resources,
administration, and management. The central server, in turn, is responsible for delivering
application logic, processing, and providing computing resources (both basic and complex) to the
attached client machines.
Centralized computing is a kind of computing architecture where all or most of the processing is
performed on a central server. It enables the deployment of all of a central server's computing
resources, administration, and management. It is used for data integrity maximization and has
many more features, advantages, and disadvantages.
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Fig no. 14: Centralized Network
Source: https://th.bing.com/th/id/OIP.l3cPXziUjxd4XK-TU4fiDwHaE8?pid=ImgDet&rs=1
 Benefits of centralized computing:
i. Data integrity is maximized data redundancy is minimized and every information can be
supplied to every place at the same time
ii. Better data preservation than other types of databases due to the often-included fault-
tolerant setup.
iii. easier data portability and data administration.
Installing centralized networks is an instant messaging platform. It can easily provide
information, ideas, and concepts to the computers or clients connected within its boundary. The
central server hosts the resources so that any user within its boundary can access the data easily.
It is advantageous to maintain centralized management of the server or network because it is the
key to the consistency, efficiency, and affordability of the system. The centralized network can
minimize the cost and expenses that are required for a system to run. The network is responsible
to maintain all the responsibilities and duties of the system.
The central server can handle all the defaults and errors occurring in the system. It can make a
decision make direct and clear decisions regarding any matter of the system. The users who work
under the centralized management system can train themselves for performing very specific
and dedicated tasks. As the central server governs all the tasks, the clients do not have to worry
about handling the activities, which saves their time and energy to invest in some other
activities of the company. A company can be operated as a unified company by management of
this network that centralizes knowledge and decisions of the system.
 Constraint of centralized computing:
i. It is highly dependent on an internet connection, if the nets go slow data access will take
more time, so data speed must be high.
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ii. There is minimal to no data redundancy, if a set of data is unexpectedly lost it is very
hard to retrieve it back, in most cases, it would have to be done manually.
The demerit that a company faces by installing or executing a centralized network is that there is
a chance of loss of data stored in this network if any disaster like water damage or electric
blackout occurs. A single Operating system is used for the entire network. It is difficult for
multiple users to maintain flexibility by using a centralized network because the users accessing
this network may have different needs but the centralized systems only allow the user to access
information on the network uniformly using the same processes. As all the data and information
are directly sent to the central server by every source of information, in case of damage to this
network, the whole data packets and information of the company will be lost. In such a case,
there will be no chance of any data being preserved or saved and the company will surely face a
huge loss. Similarly, the cost of installation or repairing the network is also quite high. There is
also a risk of hacking in this network. Being the main server, this network has to face many
errors and defaults. However, with the maintenance of security level in the network, the hackers
can attack it often. Furthermore, the network may also limit the diversity within the network and
can prevent some users from accessing the network.
Networking hardware:
Devices that are used to connect a computer to a network are known as
networking hardware. Networking hardware is required to connect multiple computers at a time
to share data and information.
Some of the following list of hardware required to set up a computer network.
 Network cables
 Routers
 Hub
 Switch
 Bridges
 Modem
 Network interface card
 Firewall
Network cables:
Network cable is one way of transmission media that can transmit
communication signals. The wired network topology uses a special type of cable to connect
computers to a network. Some of the networking cables are, unshielded twisted pair (UTP),
shielded twisted pair (STP), coaxial cable, fiber optical cable, etc.
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Routers:
The router is a communication device or networking device which is used to connect
two logically and physically different networks. The router is used to distribute the data packets
to their destination based on their IP addresses.
Hub:
Hub is a networking device that connects computers or other network devices through its
connecting points and transmits the data packet to all computers on the network when it receives
a data packet at one of its ports. Hub usually comes with 4, 8, 16, and 24. There are two types of
hubs i.e., active hub and inactive hub. Active hub checks and regenerates signal where passive
hub serves only as a physical connection point for computer devices.
Switch:
A switch is a networking device that connects computers, network devices, and network
segments through its ports. It forwards the data packet directly to the destination node when it
receives a data packet at one of its ports. A switch has many ports that can be used to connect
different network segments. A switch conserves the bandwidth and offers greater performance
than a hub. It can be sued in LAN, MAN, and WAN.
Bridges:
Bridges are similar to repeaters and network hubs. A bridge is a device that filters data
traffic at a network boundary. Bridge also reduces the amount of traffic on LAN by dividing it
into two segments. Bridges have memory buffers to queue packets. It is intelligent, only
forwards packets to the correct output
Modem (modulator and demodulator) :
A modem is a device that modulates an analog
carrier signal to encode digital information and also demodulates such a carrier signal to decode
the transmitted information. The modem is more useful in connecting LAN with the internet.
The main function of the modem is data correction, compressing data, flow control. Modern
modem work at 56 thousand bits per second or higher data transfer speeds perform automatic
error correction and allow voice and fax communications.
Network interface card (NIC):
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Network interface cards are the devices that enable computers
to connect to the network. It provides a low-level addressing system through the use of MAC
addresses. A network interface card is used to connect a computer to an Ethernet network. The
card provides an interface to the media. There are two types of networking cards i.e. External
network and internal network cards.
Firewall:
A firewall is a hardware-based network security system that controls the incoming and
outgoing network traffic based on the applied rule set. Firewalls protect internal networks from
forming public networks; they are also used to control access between specific network
segments within a network. Firewalls are essential since they can provide a single block point
where security and auditing can be imposed.
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