What is a Computer Network?

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Table of Contents
Abstract ......................................................................................................................3
Introduction ............................................................................................................... 4
Computer Network Classification ................................................................................4
Geographic Coverage: .............................................................................................4
Interconnection ....................................................................................................... 5
Administration ........................................................................................................5
Architecture ............................................................................................................5
Computer Network Types ........................................................................................... 5
A. Personal Area Network (PAN) .............................................................................5
B. Local Area Network (LAN) ..................................................................................6
C. Network of Metropolitan Area (MAN) .................................................................6
D. Wide Area Networking (WAN) ............................................................................6
Computer Network Models ......................................................................................... 7
A. OSI Model .......................................................................................................... 7
B. Internet Model ....................................................................................................7
Physical Layer ............................................................................................................ 8
A. Digital Transmission ........................................................................................... 8
B. Transmission Media ............................................................................................9
Magnetic Media ...................................................................................................9
Twisted Pair Cables ........................................................................................... 10
Coaxial Cable .................................................................................................... 10
Power Lines .......................................................................................................10
Fiber Optics .......................................................................................................11
Data Link Layer ....................................................................................................... 11
A. Error Detection and Correction .........................................................................12
Detecting Errors ................................................................................................ 12
REDUNDANCY CHECK ON A CYCLIC BASIS (CRC) .................................... 12
Data Link Control and Protocols ............................................................................... 13
A. Flow Control .....................................................................................................13
Stop and Wait ....................................................................................................13
ARQ Selective Repetition ................................................................................... 14

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Network Layer ..........................................................................................................14
A. Unicast Routing ................................................................................................ 14
B. Broadcasts Routing ........................................................................................... 15
C. Multicast Routing ............................................................................................. 15
D. Anycast Routing ................................................................................................15
Transport Layer ....................................................................................................... 16
Transmission Control Protocol............................................................................... 16
Application Layer ..................................................................................................... 16
A. Client Server Model .......................................................................................... 16
Socket ................................................................................................................... 17
Remote Procedure Call (RPC) ............................................................................... 17
Network Security Issues ............................................................................................ 17
A. Interruption ......................................................................................................18
B. Privacy Breach ..................................................................................................18
C. Integrity............................................................................................................ 18
D. Authenticity ...................................................................................................... 18
Applications ..............................................................................................................18
References ................................................................................................................ 19

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Abstract
Computer networks, also called data networks, are types of telecommunications
networks that allow computers to communicate with each other. Computer networks
use data links to carry data between networked devices. A network link is established
between nodes using either cable or wireless media. One of the world's most popular
networks is the Internet. A network node originates, transports, and terminates data on
a network. The node can be a computer, a phone, a server, or networking equipment.
Networking means sharing information between devices, regardless of whether they
are connected directly. Networks enable access to the World Wide Web, the use of
shared application and storage servers, printers, and fax machines, as well as the use
of email and instant messaging applications. Each computer network has its own
characteristics, from the physical media it uses to carry signals to its topology and
scale, as well as its organizational intent.
Keywords: Computer Networks, Network Classifications, Local Area Network,
Coaxial Cables, Network Security, Physical Layer

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Introduction
A computer network is a linked collection of computers and computerized
peripherals such as printers. This connectivity makes it easier for computers to
communicate information. Computers can connect with each other via either wired or
wireless media. Networking engineering involves the use of software, firmware, chip
level engineering, hardware, and electric pulses. To make network engineering easier,
the entire networking idea is separated into numerous levels. Each layer is in charge
of a distinct task and is independent of the others. However, practically all networking
operations rely in some manner on all of these levels.
The internet is a network that is made up of other networks. It is the biggest
network of any type in the world. The internet connects all WANs, which can also
link to LANs and residential networks. The Internet's protocol suite is TCP/IP, and IP
is its addressing protocol. IPv4 is widely utilized on the Internet in today's globe. Due
to a lack of address spaces, it is progressively moving from IPv4 to IPv6. The Internet
enables people to exchange and access vast amounts of information from across the
world. It involves use of the WebPages, FTP, email accounts, audio and video
streams, and other similar technologies. On a broad scale, the internet runs on Client-
Server architecture. Fiber optics offers an extremely fast backbone for networks.
Computer Network Classification
A computer network is a linked group of computers and computerized peripherals
such as printers. This connectivity makes it easier for computers to communicate
information. Computers can connect with each other via either wired or wireless
media. Computer networks are classified based on a variety of features. These are:
Geographic coverage, interconnection, administration, and architecture.
Geographic Coverage:
Based on its location, a network can be categorized into one of the following
categories. It can link Bluetooth-enabled devices across your desktop. There are
barely a few yards between them. It might be put throughout the structure, with

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intermediary devices linking all floors. It has the potential to blanket a whole city. It
might be dispersed throughout numerous cities or provinces. It might be a single
network that spans the globe.
Interconnection
The components of a network can be linked in a number of ways. Every device on the
network may communicate with every other device on the network, resulting in the
formation of a network mesh. All devices can be linked to a single medium, although
it is a geographically dispersed bus-like system. Because each gadget is only
connected to its peers on the left and right sides, the structure is linear. All of the
devices were linked together by a single device, making a star-like structure. All
devices were hastily linked using all prior approaches, resulting in a hybrid structure.
Administration
According to an administrator, a network can be a private network belonging to an
autonomous system and cannot be accessed outside the system's physical boundaries
or logical domain. Networks can also be accessible by the public.
Architecture
A computer network can be categorized as Client-Server, Peer-to-Peer, or Hybrid
based on its architecture. The server might be one or multiple systems. On the other
side, the User requests that the Server serve requests. The server accepts and
processes client requests.
Computer Network Types
A. Personal Area Network (PAN)
A Personal Area Network (PAN) is the most basic network that an individual may
connect to. Bluetooth-enabled or infrared-enabled devices will be included in this
category. PAN has a connection range of 10 meters. PAN can be found in wireless
computer keyboards and mouse, Bluetooth-enabled headphones, wireless printers, and
TV remotes. Pico net is a Bluetooth-enabled Personal Area Network that can link up
to eight devices in a master-slave configuration.

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B. Local Area Network (LAN)
A "local area network" is a computer network that covers a complete building and is
controlled by a single administration system (LAN). A company's LAN often
encompasses its offices, schools, colleges, and institutions. The number of systems
linked in a LAN might range from two to sixteen million. A local area network (LAN)
is a convenient way for end users to exchange resources. Printers, file servers,
scanners, and the internet may all be shared simply across machines.
Local area networks (LANs) are built with low-cost networking and routing devices.
There may be local servers that offer file storage and other locally shared applications.
It mostly use private IP addresses and does not make extensive use of routing. LANs
operate under their own local domains and are administered from a central location.
C. Network of Metropolitan Area (MAN)
The Metropolitan Area Network (MAN) is a sort of cable television network that
covers a large area. Some of the alternatives are Ethernet, Token-ring, ATM, and
Fiber Distributed Data Interface (FDDI). Metro Ethernet is a service that Internet
service providers provide (ISPs). This service allows users to expand their Local Area
Networks. MAN, for example, may let a corporation link all of its offices around a
city. The backbone of MAN is high-capacity, high-speed fiber optics. The MAN
connects the local area network to the wide area network. MAN links local area
networks (LANs) to wide area networks (WANs) or the internet.
D. Wide Area Networking (WAN)
As the name indicates, a Wide Area Network (WAN) covers a broad area that may
cover provinces or perhaps the whole country. Telecommunications networks are
frequently Wide Area Networks. These networks link together MANs and LANs.
Because they have a highly fast backbone, WANs require relatively costly network
equipment. Advanced WAN technologies include Asynchronous Transfer Mode
(ATM), Frame Relay, and Synchronous Optical Network (SONET). The WAN may
be overseen by many authorities.

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Computer Network Models
A. OSI Model
The OSI model was developed by the International Standard Organization (ISO) .
This model is made up of seven layers: The OSI Model Application Layer is in charge
of interacting with the application's user. This layer includes protocols that interact
with the user directly. This layer specifies how data in the remote host's native format
should be displayed in the host's native format. The Session Layer manages sessions
between distant hosts. For example, once user/password authentication is complete,
the remote host waits a certain amount of time before requesting authentication again.
The Transport Layer is in charge of delivering data from one host to another. The
Network Layer is in charge of allocating addresses and addressing hosts in a network
in a unique way. The Data Link Layer handles data reading and writing to and from
the line. Link errors are recognized at this layer. The physical layer, among other
things, defines the hardware, wiring, power output, and pulse rate.
B. Internet Model
On the Internet, the TCP/IP protocol suite, often known as the Internet suite, is
utilized. The Internet Model, which has a four-layered design, is defined in this way.
The OSI Model is a broad communication model, whereas the Internet Model is the
communication model employed by the internet. The internet, like the network
architecture that supports it, is self-contained. This model's layers are as follows: The

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Internet Model Application Layer defines the protocol that allows users to interact
with the network. Examples include FTP, HTTP, and other protocols. This layer
establishes the protocol for data transport between hosts. At this layer, the
Transmission Control Protocol is the most significant protocol (TCP). This layer is in
charge of end-to-end delivery and guarantees that data is sent in the right sequence
between hosts. The Internet Protocol (IP) is implemented at this layer. This layer
simplifies the process of addressing and recognizing hosts. The Link Layer is in
charge of transmitting and receiving data. Unlike its OSI Model counterpart, this layer
is not affected by the underlying network architecture or hardware.
Physical Layer
The physical layer interacts with actual hardware and signaling systems in the OSI
model. The OSI network model's physical layer is the only one that deals with the
physical connection between two stations. This layer, among other things, defines the
hardware, cabling, wiring, frequencies, and pulses required to represent binary
signals.
The Physical layer provides services to the Data-link layer. The data link layer sends
frames to the physical layer. The physical layer converts them to electrical pulses,
which represent binary data. The binary data is then transferred over wired or wireless
media.
The two approaches for storing data or information are analog and digital storage. For
a computer to use the data, it must be in a distinct digital format. Signals, like data,
can be analog or digital in nature. Before data can be delivered digitally, it must first
be converted to digital form.
A. Digital Transmission
Line coding and block coding are the two ways for converting digital data into digital
signals. All communications must use line coding, but block coding is optional.
The technique of converting digital data into digital signals is known as line coding.
The most frequent type of digital data is binary data. It's represented (stored)
internally as a series of 1s and 0s. A digital signal is defined as a discrete signal that
represents digital data. Line coding techniques are divided into three categories.

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Unipolar encoding techniques use a single voltage level to encode data. High voltage
is given to represent binary 1 in this case, whereas no voltage is sent to represent
binary 0. It's also known as Unipolar Non-return-to-zero since there's no rest
condition. It represent either 1 or 0.
Polar Encoding is a type of coding that is used to encode data. In the polar encoding
approach, binary information is represented by several voltage levels. Polar encodings
may be divided into four categories: Non-Return to Zero in the Polar Regions (Polar
NRZ) is a binary value representation that uses two voltage levels. Positive voltage
equals 1 in general, while negative voltage equals 0. Due to the lack of a rest period, it
is also NRZ. NRZ-L and NRZ-I are the two sections of the NRZ system.
NRZ-L changes voltage level when a different bit is detected, while NRZ-I changes
voltage when a 1 is discovered in NRZ Unipolar. The issue with NRZ is that if the
sender and receiver clocks aren't in sync, the receiver won't be able to tell when one
bit ended and the next one began. Return to the beginning (RZ) The term "return-to-
zero" refers to the process of going back to zero. Positive voltage denotes one,
negative voltage denotes zero, and zero voltage indicates none. Signals change in
between bits, not in the middle of them. When RZ and NRZ-L are coupled in this
encoding scheme, it is known as the Manchester case. A bit's duration is divided into
two parts. It changes phase and transits in the middle of the bit when a different bit
meets it.
B. Transmission Media
The transmission media in computer networks are the physical means via which
communication takes place.
Magnetic Media
Even before networking, one of the most practical methods of transferring data from
one computer to another was to store it on storage media and physically transfer it
from one station to another. Magnetic media, however it may appear outdated in
today's age of high-speed internet, comes into play when the volume of data is vast. In
these cases, data backup is recorded on magnetic tapes or magnetic discs and then
physically relocated to remote locations.

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Twisted Pair Cables
Twisted pair cables are made up of two plastic-insulated copper wires that are twisted
together to form a single medium. Only one of these two cables sends an actual
signal, while the other acts as a ground reference. Twisting wires together can
minimize noise (electromagnetic interference) and crosstalk. Twisted pair cables are
classified into two types: Cable STP (Shielded Twisted Pair) UTP (Unshielded
Twisted Pair) cable is a type of unprotected cable.
In STP cables, the twisted wire pair is coated in metal foil. As a result, it's less
sensitive to noise and crosstalk. UTP is separated into seven categories, each having a
unique range of uses. In computer networks, Cat-5, Cat-5e, and Cat-6 cables are often
used. UTP cables are connected using RJ45 connections.
Coaxial Cable
Coaxial cable is made of copper wires. The core wire, which is made of solid
conductor, is in the center. The core is surrounded by an insulating layer. The second
wire is wrapped around the sheath and then around the insulator sheath. A plastic
cover protects everything. Because of its structure, coax cable can transport higher
frequency signals than twisted pair cable. Because of the wrapped structure, it boasts
outstanding noise and cross talk prevention. Coaxial cables may give bandwidth of up
to 450 mbps. Coax cables are classified into three types: RG-59 (Cable TV), RG-58
(Thin Ethernet), and RG-11 (Thick Ethernet). The abbreviation for Radio Government
is RG. To connect the cables, the BNC connector and BNC-T are utilized. The wire is
terminated at both ends with a BNC terminator.
Power Lines
Power line communication is a Layer-1 (Physical Layer) technique that uses power
lines to transport data messages (PLC). Modulated data is transferred via a PLC's
cables. Because power lines are widely utilized, the data is de-modulated and
processed by the receiver on the other end. A PLC may manage and monitor any
powered devices. The PLC is set to operate in half-duplex mode. PLCs are classified
into two types: programmable logic controllers (PLCs) and programmable PLCs with
narrow band. PLC with a broad frequency range Narrow band PLCs provide reduced
data rates of up to 100s of kbps since they operate at lower frequencies (3-5000 kHz).

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They may be found over a wide range of distances. Broadband PLC runs at higher
frequencies (1.8–250 MHz) and provides data speeds of up to 100s of Mbps. They
cannot be expanded as far as Narrowband PLC.
Fiber Optics
Fiber Optics is a type of optical fiber that is used in communications. Fiber Optics is
based on the properties of light. A light beam refracts at a 90-degree angle when it
encounters a critical angle. This property has been exploited in fiber optics. The core
of a fiber optic cable is made of high-quality glass or plastic. Light is emitted from
one end, travels through it, and is detected and converted to electric data by a light
detector at the other end.
Fiber optics is the most efficient mode of transmission. It comes in two varieties:
single mode fiber and multimode fiber. A single mode fiber can only carry one light
ray, but a multimode fiber can carry several beams.
Data Link Layer
The second layer of the OSI Layered Model is the Data Link Layer. This layer is one
of the most difficult to perceive, since it has a variety of functions and threats.
The data connection layer hides the underlying hardware characteristics and presents
itself as a communication channel to the higher layer. The data connection layer joins
two hosts that are directly linked in some way. This direct connection can be either
point-to-point or broadcast. Systems on a broadcast network are said to be on the
same connection. The data connection layer's duty gets more difficult when dealing
with several hosts on a single collision domain.
The data connection layer is in responsible of converting data streams to signals bit by
bit and delivering them across the underlying hardware. The Data Link Layer takes
data from hardware as electrical impulses, assembles it into a recognized frame
format, and transfers it on to the higher layer. The data connection layer is divided
into two sub-layers: logical link control, which covers protocols, flow control, and
error control. The real management of media is handled by Media Access Control.

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A. Error Detection and Correction
Data can be corrupted during transmission due to a number of factors such as noise,
cross-talk, and so on. Upper layers are unaware of real hardware data processing and
rely on a fictitious representation of network architecture. As a result, higher levels
expect flawless system communication. The majority of programs will not function
properly if they get inaccurate data. Voice and video apps may not be as affected as
other programs, and even if they are, they may still function well. The data-link layer
includes several error control algorithms to ensure that frames (data bit streams) are
transmitted with a certain degree of correctness. However, in order to understand how
mistakes are controlled, it is vital to first understand the many types of errors that
might occur.
Detecting Errors
To detect errors in received frames, the Parity Check and Cyclic Redundancy Check
are utilized (CRC). In both cases, a few extra bits are sent in addition to the actual
data to guarantee that the bits received at the other end match the ones sent. If the
counter check at the receiver fails, the bits are considered corrupted.
When even parity is used, an additional bit is broadcast together with the original bits
to make the number of 1s even, and when odd parity is used, an additional bit is
transmitted along with the original bits to make the number of 1s odd. As a frame is
formed, the sender counts the number of 1s in it. When using even parity and the
number of ones is even, for example, one bit with the value 0 is added. In this way,
the number of 1s will remain constant. If the number of 1s is odd, a value of 1 is
added to even things out.
REDUNDANCY CHECK ON A CYCLIC BASIS (CRC)
CRC is another mechanism for detecting whether or not the data in the received frame
is genuine. This approach employs binary division of the data bits being transferred.
The divisor is created using polynomials. The transmitter divides the bits being
communicated and computes the remainder. Before transferring the remaining bits,
the sender adds them to the end of the genuine bits. A codeword is a group of data bits
plus the remainder. The transmitter sends data bits in code words.

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Data Link Control and Protocols
The data-link layer is in charge of point-to-point flow and error management.
A. Flow Control
When transmitting a data frame (Layer-2 data) from one host to another across a
single medium, the transmitter and receiver must both run at the same speed. In other
words, the transmitter sends data at a rate that the receiver can process and accept.
What if the sender's and receiver's (hardware/software) speeds differ? If the
transmitter transmits too fast, the receiver may get overloaded, resulting in data loss.
There are two techniques for regulating the flow:
Stop and Wait
After transmitting a data frame, this flow control method forces the sender to slow
down or stop and wait for the data frame to be acknowledged. Stop and Wait Sliding
Window In this flow control mechanism, both the sender and the receiver agree on the
number of data frames after which the acknowledgement should be given. Because
the stop and wait flow control approach wastes resources, this protocol tries to make
the most of the underlying resources.
ARQ Stop and Wait
The following transition may occur in Stop-and-Wait ARQ: The sender keeps a
timeout counter. When a frame is sent, the sender starts the timeout counter. If the
sender gets acknowledgement of the frame within a reasonable amount of time, the
sender transmits the next frame in the queue. If the sender does not get
acknowledgement within a reasonable period, the sender believes that the frame or its
acknowledgement has been lost in transit. The sender retransmits the frame, and the
timeout counter begins. The frame is resent if the sender receives a negative
acknowledgement.
ARQ-Back-N
The ARQ mechanism makes poor use of available resources. When the
acknowledgement is received, the sender does nothing. In the Go-Back-N ARQ
approach, both the transmitter and the receiver keep a window open. Back-n-ARQ is a

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command that allows you to return to a previous point in time. The sending-window
size enables the sender to send many frames without waiting for the previous ones to
be acknowledged. The receiving-window enables the receiver to receive and
acknowledge many frames at the same time. Each arriving frame's sequence number
is recorded by the receiver.
After transmitting all of the frames in the window, the sender checks to verify which
sequence number received affirmative acknowledgement. If all of the preceding
frames have been acknowledged positively, the sender transmits the next batch of
frames. If the sender receives NACK or no ACK for a specific frame, it retransmits all
of the frames until it receives a positive ACK.
ARQ Selective Repetition
In Go-back-N ARQ, the receiver is assumed to have no buffer space for its window
size, therefore each frame must be processed as it comes. Any frames that have not
been acknowledged are resent by the sender. The receiver buffers the frames in
memory while keeping track of the sequence numbers, and transmits NACK for just
the frames that are missing or damaged in Selective Repeat ARQ.
Network Layer
When a device has many paths to a goal, it always choose the one it favors over the
others. This procedure of selecting is referred to as routing. Routers, which are
particular network hardware, or software processes can do routing. Software-based
routers have a limited functionality and range. A router's default route is always
configured. A default route informs the router where to deliver the packet if no route
for that destination can be found. If there are several pathways leading to the same
goal. Routes can be established dynamically or put up statically. It's possible that one
path will be prioritized above others.
A. Unicast Routing
The most of internet and intranet traffic is transmitted to a single destination, often
known as Unicast data or Unicast traffic. The method of delivering Unicast data
across the internet is known as Unicast routing. It is the simplest sort of routing

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because the destination is already known. As a result, the router's only responsibility
is to verify the routing table and forward the packet to the next stage.
B. Broadcasts Routing
Broadcast packets are not routed and broadcast by routers by default on any network.
Routers generate broadcast domains. However, under specific conditions, it may be
configured to forward signals. At the same moment, a broadcast message is delivered
to all network devices. There are two ways to route transmissions (algorithms): A
router creates a data packet and sends it one at a time to each host. In this case, the
router creates several copies of the same data packet with different destination
addresses. Although all packets are Unicast, because they are sent to anyone , the
router seems to be broadcasting.
C. Multicast Routing
Multicast routing is a subset of broadcast routing with its own set of features and
challenges. Packets are sent to all nodes, even if they do not want them, using
broadcast routing. Data, on the other hand, is only provided to nodes that want to
receive packets when using Multicast routing. Only after determining that there are
nodes that desire to receive multicast packets (or streams) should the router forward
them. Multicast routing use the spanning tree protocol to avoid looping. Multicast
routing utilizes the reverse path forwarding approach to detect and reject duplicates
and loops.
D. Anycast Routing
Multiple hosts can share the same logical address due to anycast packet forwarding.
When a packet with this logical address is received, it is sent to the routing topology's
nearest host. Anycast routing is performed by the DNS server. When an Anycast
packet is received, the DNS server is considered to determine where it should be
delivered. DNS delivers the IP address of the system's closest to the configured IP
address.

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Transport Layer
Transmission Control Protocol
The Transmission Control Protocol is one of the most important protocols in the
Internet Protocols suite (TCP). It is the most widely used data transmission protocol in
communication networks like the internet. TCP is a reliable protocol. That is, the
receiver always provides the sender with either a positive or negative
acknowledgement of the data packet, so the sender always knows if the data packet
has reached at its destination or whether it has to be resent. TCP ensures that data
arrives at its destination in the same order in which it was transmitted.
TCP is a protocol that manages connections. TCP demands that a connection be
established between two distant places before transferring data. TCP includes an
error-checking and recovery mechanism. TCP is used for end-to-end communication.
TCP is responsible for flow control and service quality. TCP operates in a point-to-
point Client/Server mode. TCP is a full-duplex server, which implies that it may
function as both a receiver and a broadcaster.
Header
TCP headers must be at least 20 bytes in length and no longer than 60 bytes in length.
TCP Header Source Port (16 bits) shows the source port of the application process on
the transmitting device. The destination port (16 bits) of the receiving device's
application process is shown. Sequence Number (32 bits) - The number of data bytes
in a sequence segment of a session. When the ACK flag is set, this number comprises
the next sequence number of the expected data byte and acts as an acknowledgement
of the data received before. Data Offset (4 bits) - This field specifies both the size of
the TCP header (32-bit words) and the offset of data in the current packet across the
TCP segment.
Application Layer
A. Client Server Model
Two remote application processes may interact primarily in one of two ways: Peer-to-
peer: Both remote processes operate simultaneously and share data through a common
resource. Client-Server: One remote process acts as a Client, seeking resources from

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another remote application process that acts as the Server. In a client-server
architecture, any process can act as either a server or a client. The ability to satisfy
requests, rather than the type of computer, size, or processing capability, characterizes
a system as a server.
At the same time, a system can function as both a server and a client. In other words,
one process acts as a server, while another acts as a client. It's also possible that the
client and server processes are operating on the same system.
Socket
The Server process in this model establishes a socket on a well-known (or known by
the client) port and waits for a client request. The second process, which operates as a
Client, also opens a socket, but instead of waiting for an incoming request, it
processes' requests first. When the request reaches the server, it is delivered. It might
be a request for information or for resources.
Remote Procedure Call (RPC)
Procedure calls are a way for one process to communicate with another. One process
is responsible for the operation on the remote host (client). The name of the remote
host's process is Server. Both processes have stubs allocated to them. This discussion
takes place as follows: The client process refers to the client stub. It communicates to
it all of the program's local parameters. The arguments are then bundled and routed to
the other end of the network through a system call. The kernel sends data across the
network, which the other end receives. Data is transferred from the remote host to the
server stub. After the parameters are passed to the procedure, it is executed. Similarly,
the result is returned to the client.
Network Security Issues
During the early days of the internet, it was largely utilized for research and
development by the military and universities. Before all networks merged to form the
internet, data flowed through public transit networks. Ordinary people may send
incredibly sensitive data, such as bank credentials, usernames and passwords,
personal papers, online shopping information, or private documents. All security

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threats are intentional in the sense that they only appear when they are intentionally
engaged. The many sorts of security risks are as follows:
A. Interruption
Interruption is a security issue that affects resource availability. For example, a user
may be unable to connect to his or her web server, or the web server may have been
hacked.
B. Privacy Breach
Under this threat, the user's privacy is threatened. Data transmitted or received by the
original authenticated user is being accessed or intercepted by an unauthorized party.
C. Integrity
Any adjustment or change to the original context of communication is seen as a
threat. The attacker intercepts and acquires the sender's data, then modifies or
produces false data before delivering it to the receiver. The data is received by the
receiver as if it had been sent by the original Sender.
D. Authenticity
It is dangerous when an attacker or a security breach poses as a legitimate person and
obtains access to resources or communicates with other legitimate users.
Applications
A network is made up of computer systems and peripherals that are linked together.
They have a lot of benefits. Some of them include Shared resources include printers
and storage devices. E-mail and FTP are used to share information. Information
sharing through the web or the Internet Using dynamic web pages to communicate
with others Internet Protocol phones (IP). Meetings are held through videoconference.
Parallel processing Messages are sent immediately.

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