Analysis of Data Communications, TCP/IP and Network Security Protocols

This report provides a comprehensive overview of data communications, focusing on TCP/IP and network security protocols. It begins with an introduction to digital communication, explaining the flow of information and the importance of accurate and accessible data transfer. The report then delves into the types of digital communication, including analog and digital transmission, and explores various signal encoding methods such as NRZ, NRZI, Manchester, and bipolar encoding. It also examines different modulation techniques, including amplitude modulation (AM), frequency modulation (FM), phase modulation (PM), and shift keying methods (ASK, FSK, PSK). The report further discusses the TCP/IP protocol, explaining its role in connecting network devices and ensuring reliable data transmission, along with a breakdown of the OSI and TCP/IP model layers. Finally, it highlights the advantages of digital communication and the differences between TCP and UDP communication, offering insights into wired and wireless data transfer methods.

DATA COMMUNICATIONS, TCP/IP AND NETWORK
SECURITY PROTOCOLS

ABSTRACT
The study focuses on digital communication,
TCP/IP communication protocol, and
network security protocols. It also clearly
states about the modulation techniques,
protocols used in the TCP or IP and the
different types of protocols used in each
layer of the OSI model. Moreover, the
importance of each method is described.
INTRODUCTION TO DIGITAL
COMMUNICATIONS
Data communication is one of the sources of
the information that flows through the
internet .information can be shared from
place to place within a fraction of a second.
Data communication is one of the resources
that people need day by day and all the
routine that is performed in the day are
processed using Data. Due to the rapid
increase in the technology the people can
track the data and get information from the
data in real time. This information gathering
is possible through Data communication.
We expect the information should be
accurate and accessible 24x7 this kind of
service is achieved by the physical
components and the speed of the
communication that happens between the
hardware.
The information that is to be passed from
one people to other people through a mode
of communication can be analog or digital
communication. Both communication modes
are used in nowadays due to the fact the
Analog communication is old technology is
also used in communication method is some
applications because of the improvement of
technology all the analog interface is turned
into digital information
TYPES OF DIGITAL
COMMUNICATION
There are two types of digital
communication. They are analog
transmission and digital transmission.
ANALOG TRANSMISSION
Analog transmission is the process of
converting the voice information, image,
data in the form of continuous signal that
can be varied using such parameters as
phase, amplitude or some properties. The
signal could be transferred using some
mechanisms like analog modulation and
frequency modulation.
DIGITAL TRANSMISSION
Digital transmission is the process of
converting the information using some
physical medium that can be delivered in the
form of digital signals. The information
could not be transmitted in the form of 0’s
and 1’s. it must be transmitted in the form of
signals.
The signals can be encoded using the
following encoding methods.
Signal encoding
This method is used for encoding the digital
signal and transmitting in the form of
physical medium. It can be of two types they
are two level encoding methods and three
level encoding methods.

Two level encoding method
In this method of encoding, the signals with
the positive value or negative value are
considered for converting the signal through
the physical medium.
Three level encoding method
In this method, three values are considered
for encoding the signals. The values are a
positive value, zero and negative values.
With these values, the signals are encoded
and transmitted through the physical
medium.
NRZ encoding method
NRZ means No return to Zero. It is the
simplest encoding method which is used for
transforming the input signals from 0 to
negative values and 1 to positive values.
This method of encoding methods is used
for delivering the output to know the
presence of a signal.
NRZI encoding method
NRZI is an entirely different form of NRZ
encoding method. During the transmission
bit if the value of the bit is 1, the clock state
will change. If the value of the bit is 0, the
clock state will not be changed.
Manchester encoding method:
This encoding method is performed using
the XOR method and translating the zeros
and ones with the XOR operation.
Delay encoding method:
It is similar to Manchester encoding method
where the data bit changed during the
middle of the transmission methods.
Bipolar encoding method:
In this encoding method, there are three
methods of transmission. If the bit is 0 then
the value of the bit will also be 0. If the bit
value is positive or negative value the value
will be 1.
TYPES OF MODULATION
TECHNIQUES
Modulation is divided into two types
namely, Analog and digital modulation.
Types of analog modulation are AM, PM,
FM, PWM and types of Digital modulation
are IO, PSK, FSK, and ASK.
AMPLITUDE MODULATION (AM)
Amplitude modulation is a former most used
modulation technique that used to transmit
voice via radios. This is used as a
modulation technique in electronic
communication as one of the parts. In
amplitude modulation, the carrier signal of
amplitude oscillates due to the message
signal and produce difference variables in
phase and consistent frequency. There will
be a modulation shortage due to the power
fluctuation, bandwidth increasing capacity,
and filtering. Used in PC modems, VHF
radios, portable radios.
FREQUENCY MODULATION (FM)
In frequency modulation, the carrier signal
on which the frequency transfers differs as
per message signal and amplitudes may
differ, but the phase remains constant.
Applications like radar, radio telemetry,
protecting monitoring seizures. This is
mostly used in broadcasting voice or music,
a recording system that uses magnetic tapes,

2-way radio system and system that transfer
videos. It will cancel the noise during radio
systems.
PHASE MODULATION (PM)
In phase modulation, the carrier signal on
which the phase transfers changes according
to the message signal. If the phase of the
signal changed it affects the frequency.
Phase modulation is used in applications that
use transmitting waves like GSM, Wi-Fi,
and Satellite TV.
AMPLITUDE SHIFT KEY (ASK)
The carrier amplitude can vary with the
proportion to message signal in amplitude
shift key. A modulated carrier signal in
amplitude signal is called carrier signal. The
input data is in on and off signal so the
output is also like one and off signal and 1
indicates the available signal and 0 indicates
the missing signal. Fibre optical transmitter
and receivers, IR remote, uses amplitude
shift keys.
FREQUENCY SHIFT KEY (FSK)
Whenever the changes on data transmitted
on frequency signal there will be a
frequency shift key. The frequency of this
modulation is wc1 and wc2. Wc1 will
transmit when the data bit is 1. Modems use
frequency shift keys.
PHASE SHIFT KEYS
Modulation that is changed due to phase and
uses on and off shift methods is phase shift
key. The baseband signal is 1 when a carrier
is transmitted. Same as amplitude and
frequency it uses on and off method to
change the phase when on offside it
indicates as 0 i.e. carrier is not transmitted.
During the off set they can send 2bits of data
at a particular time as during this they were
4 quadrants that help to increase the speed of
the phase shift.
ADVANTAGES OF DIGITAL
COMMUNICATION
 It consumes high power
 It requires more bandwidth for
transmission when compared to the
analog systems.
 The sampling error of analog
transmission is high

INTRODUCTION TO TCP/IP
TCP/IP –Transmission Control
protocols / Internet protocols are the
communication protocols on the internet that
are used to connect network devices. TCP/IP
has a set of rule that explains how a data are
travelled and exchange data on a network
channel, which provides an end-to-end
communication. During transmission of
data, it should tell how a data are split into
packets, provide a smart and less time-
consuming route to deliver packets, Provide
an address to the receiver send, finally how
data's are received at the receiver place.
TCP/IP is used mostly for reliable
communication over the internet and allows
one to recover the loss of connection
automatically on the network.
This TCP/IP has a main role in an
Application layer on OSI layer. Each has its
own responsibilities where TCP explains
about the communication channel on how a
data has to transmit and before data
transmission; it explains how data has
assembled into small packets and at receiver
end how it should rearrange the data
packets. Whereas IP explains about the
application, address and route on packets
that helps to reach the destination correctly.
On each entry to the system, an IP address is
checked so that it directs them to right target
with the correct order.
Working with TCP/IP protocol
Client/server communication model uses a
TCP/IP protocol where an end user needs a
service from another system that acts as a
server. TCP/IP is a stateless protocol where
every client connection is considered as a
new connection that helps to provide a
traffic-free connection.
Figure 1: OSI and TCP/IP model
TCP/IP Protocol Suite
TCP/IP protocol has four Layer
model namely, Application layer, Transport
layer, Internet layer and Network interface
layer or physical layer.
Figure 2. TCP protocol suite
NETWORK INTERFACE LAYER
This layer is called network access
layer where a data are sent through a
physical medium. During this
communication, TCP/IP use to communicate
with the different system using LAN
technology like Ethernet, wireless medium
802.11 and WAN technology. Frame relay
and Asynchronous transfer mode are some
WAN technology used for communication.

TCP/IP on network interface layer can adopt
new versions and technologies. This is to
provide the reliable service between one
system to another system.
NETWORK LAYER
Network Layer or Internet Layer has
responsibilities to provide addressing,
splitting the data into packets, find the exact
route. Network layer has IPv4 and IPv6
address.
IPv4 Internet layer
Address resolution protocol provides a
hardware address that change to network
interface layer to transfer on a network
channel.
Internet protocol helps to show the route and
a routable protocol that show the address,
the route to reach the destination.
ICMP Internet control message protocol
helps to report if an error occurs and
contains information about unsuccessful
delivery. This helps to recover if packet
losses during delivery.
Internet group management protocol uses to
accomplish IP multicast group.
IPv6
IPv6 is similar to IPv4 it also a routable
protocol to address and provide a route to
packets.
Internet control message protocol for IPv6
(ICMPv6) reports the occurrence of error
and information to help them to recover the
loss of packets during unsuccessful delivers.
Neighbour Discovery (ND) maintains the
collaboration between the near nodes.
Multicast Listener Discovery (MLD) this
protocol helps to maintain and listen to
multicast of the Ipv6 groups.
TRANSPORT LAYER
This layer of TCP/IP allows the session and
datagrams for communication. This has a
responsibility to transfer the data in either
TCP or UDP.
Types of communication
The people who are using the technology
will use may end up two medium wired
types of communication and wireless
communication, people need the information
quickly and accurately so people use TCP
and UDP communication.
The communication is done with wired
communication and wireless communication
the people in the
TCP communication is used for wired
communication in the older technology
people used the wire communication with
this technology they send the information
with packets and they wait for the
acknowledgment to be sent. The packets
which are sent to the user should wait for the
remaining packet to be received in the same
order that they received.
Analog communication is where sending the
frequency though electric signals this signal
consists of sin waves and cosine waves. The
digital signals are got through sampling the
electric signals.

UDP communication
This type of communication is used for
transferring data through wireless
communication because transferring the
packet through the internet the packets are
sent in random order the order need not be
arranged to receive the data from the
receiver.
This facility allows multiple users to accept
the receive the packets in parallel Real-time
applications.
Because we can’t relay on the network the
network will not give the efficient transfer
rate and there will be always latency in the
network. Due to this many application uses
UDP for getting the information from the
remote areas where the particular
infrastructure cannot be implemented.
For example, we are to consider a company
where the company headquarters in one
place and the company want to establish a
remote place where all the data have to be
transferred .the admin of the company can
establish the wireless access point so that
information can be sent through the internet
which is secured transfer the information.
TCP is a transmission control protocol that
is reliable, end-to-end communications.
Every TCP connection has a report about
successful connection, their sequence and
acknowledges about the packets sent to
destination. If packet loses then it helps to
recover the packets that lost in
communication. This is connection-oriented
protocols.
UDP is a user datagram protocols that
provides one-to-one and one-to-many
communication, connectionless and
unreliable communication that carries data
as datagrams.
Both use IPv4 and IPv6 address layer.
APPLICATION LAYER
This allows accessing the application and
providing services that help to exchange the
data between the applications. There are
many protocols in the application layer that
helps to communicate between different
applications on the different system.
HTTP – Hypertext Transfer Protocol: Files
that are in World Wide Web as a page.
FTP – File Transfer Protocol: Helps to
transfer files over the application.
SMTP – Simple mail Transfer Protocol:
Helps to transfer messages and attachments
in mail.
DNS – Domain Network System: This
converts the hostname into IP address so
that it will be easy for the system to identify.
These make copies a name from one DNS to
another DNS server.
RIP – Routing Information Protocol: Helps
to provide the smart route to exchange the
route information to routers in the IP
network.
SNMP – Simple Network Management
Protocol: This helps to collect and manage
the networks information about their
management console and device that present
on network. Device like routers, bridge,
switch and servers are present on the
network.

IPv6 Internet Layer: Protocols present in the
IPv4 internet layer is ARP, IPv4, ICMP and
IGMP.
ARP
Address resolution protocols help to convert
the address for easy transmission over
network channels. Whenever an Internet
protocol receives a packet from another
system on physical channels like wired or
wireless, it converts the MAC address to its
IPv4 address format. This will address the
nodes to reach its destination.
This is called next-hop IPv4 address that
converts the MAC address to Ipv4 address.
IPv4 address destination says the route and
determines the next-hop i.e. next step to
reach the router.
At the receiver end, it preforms ARP to
convert the IPv4 back to the MAC address.
ARP uses a broadcasting service on the
medium or shared resource to request frame.
The sender will receive back the reply ARP
frame that has a MAC address with its IPv4
address.
IPv4 Internet protocol version 4
Figure 3. IPv4
A datagram protocol needs transmission as
addressing and routing packets from
different. This is a connectionless and
unreliable protocol, which means that does
not begin a connection before exchanging
and no guaranteed delivery during the
transaction.
IPv4 header has an address of the source or
destination IP address and Payload are the
messages that carried during transmission.
OSPF
Open Shortest Path First (OSPF) is used
in interior gateway protocol, for the use of
the independent system with the remote
location on the mind where the LAN will
play the major role in the communication it
uses the famous Dijkstra algorithm.
The main goal of the algorithm finds the
shortest path of the network from one node
to another node. The information gathered is
sent to the RIP routing information protocols
and calculation is done by counting the
number of hops that are taken to reach the
designation . This is why the dynamic
routing take please because the IP to a
particular system is not fixed it may change
any time.
OSPF was designed to give the cost-efficient
solution to the user.
OSPF checks for any changes in the
designation of the node and quickly it will
adapt to it .it has to check for the bandwidth
and amount resources is using should not be
more than expected cost because the
network should not contain the latency as
well it should be cost-effective.
ICMP (Internet Control Message
Protocol)
This helps to report the occurrence of errors
and recover from unsuccessful deliveries. If
IPv4 does not deliver a packet during
transmission of data’s to destination system
or host then ICMP that present on the router

sends the message that “message is
unsuccessful” to the sender.
Echo, Echo Reply, Redirect, Quench from
source and unreachable to the destination are
the some of the error messages that sends to
the sender whenever an error or loses of
packets occurs.
Destination Unreachable has different error
message according to where the packets lost
during transmission. Host unreachable,
Protocol unreachable, port unreachable, and
segment need to set are the destination
unreachable error message. Whenever a
system has an error in finding the
destination then these messages are
broadcast to the sender.
IGMP – Internet Group Management
Protocol
For the multicast groups on the network,
IGMP protocol is used to manage the
protocols on routers and the host system.
This listens to the IPv4 traffic for single
MAC address and processed to IPv4 hosts.
To communicate with host group it uses
IPv4 casting to span the routers among the
internet protocol.
Internet Protocol IPv6
This is similar to IPv4 protocol but it works
for both IPv6 and IPv4. IPv6, ICMPv6, ND,
MLD are the protocols present in the IPv6.
IPv6
This is connectionless protocol like IPv4,
Unreliable datagram protocol responsible for
addressing and routing of packets between
the host.
The header has an address for source and
destination address that helps to find the
route during packet transmission.
ND – Neighbor Discovery
A set of an ICMPv6 protocol messages
helps to determine what the relationship
between the neighbour nodes during
communication.
This helps to discover the neighbour router
and discover the route address to reach the
destination.
ND on routers helps to show their presence
among the routing nodes, host address and
inform the next-hop to reach next router.
MLD – Multicast Listen Discovery
This is a message control protocol in IPv6
that helps to exchange the message between
nodes and routers. To enable the router by
discovering multicast address members on
IPv6 were the listing nodes are to perform
next-hop.
Three message on Multicast listen to
discovery to report messages. They are a
query, report and done message.
Example for application programming
interface
Consider the socket program in windows
with BIOS API.

Figure 4: netBIOS
Windows application uses windows socket
and an API for networking applications.
Client-server communication program is an
example of TCP/IP service where windows
socket is used. During connection phase,
sockets help to connect using IP address and
a port number, creating connection and ping
connections to targeted destination host
using its IP address and its port number.
BIOS API
It provides some name management, session
service and datagram to BIOS application.
NetBIOS application uses NetBIOS API and
this interface API for communication over a
network. Even if it works with windows
then any service on these protocols,
implement with the support of NetBIOS
API.

INTRODUCTION TO NETWORK
SECURITY PROTOCOLS
Network security protocols are used for
providing the security of data during the
communication over the internet. These
protocols help to define some methods and
steps for securing the data from any illegal
access. They are mainly designed for
preventing the data from the unauthorized
person. The key concepts used by the
network security protocols are cryptography
algorithms and encryption mechanism.
Special algorithms are used for decrypting
the encrypted data with the private key or
logical key. Examples of network security
protocols include Secure Socket Layer
(SSL), File Transfer Protocol (FTP),
Transport Layer Security (TLS), Pretty
Good Privacy (PGP) and Hyper Text
Transfer Protocol (HTTPs).
Since the growth of growth internet is
rapidly increased the need for security
protocols is increased to secure the data. The
demand for security protocols is increased.
Each layer in the OSI model has separate
protocols to secure the data communication.
They are listed as follows
DATA LINK LAYER
The following protocols are used in the data
link layer.
 Point to point protocol (PPP)
 Remote Authentication Dial-in User
Service (RADIUS)
 Terminal Access Controller Access
Control System (TACACS+)
Point-to-Point Protocol (PPP)
Point to point protocol is used for providing
the constant way of transferring the data
over point to point connection. To perform
this transformation there are three
components are available in point to point
protocol. They are datagram, link control
protocol and data link connection. The
datagram is used to combine the multi data
packets. Link control protocol is used for
establishing and configuring the connection
between the network protocols.
In early days of communication, people use
the modem for the internet connection so
there is a need of a point to point protocol.
This protocol is needed when there is a need
for single data link communication. For
establishing the connection Remote access
Server (RAS) is responsible. It will direct
access to the user and provide authentication
for the further communication.
The communication of point to point
protocol starts with the handshake process
so that it provides the message to start the
communication with authentication or not. If
the user wants to communicate then the
authentication is provided to start the
communication. If the user should not
communicate then authentication is not
provided to start the communication. This
process can be performed using Link
Control Protocol (LPC).
Remote Authentication Dial-in User
Service (RADIUS)
Remote authentication dial-in user server
acts as a server for providing the remoter
authentication and dial-in security services.

It involves two protocols namely Challenge-
Handshake authentication protocol (CHAP)
and Password Authentication Protocol
(PAP). This protocol is used by the Internet
Service Providers (ISPs) for providing the
authentication for the remote users.
Terminal Access Controller Access
Control System (TACACS+ )
This protocol is widely used for providing
the authenticated service. It is used for dial-
up connection for providing authorization,
authentication and auditing.
Authentication: it uses different
authentication mechanisms
Auditing: it holds the record of users
process where it contains the services and
security used by the user.
Network layer:
The following protocols are used in the
network layer they are
 IPSec
 VPN
Internet Protocol Security (IPSec)
IPSec is used for providing the
authentication and encryption of data which
is transferred on the internet. The design of
the internet has less security. It provides
Access control, confidentiality,
authentication and replay protection for the
network layer. In Internet Protocol Security
two mode of communication is followed.
They are transported mode and tunnel mode.
Transport mode:
In transport mode, the communication is
provided from the host to host method
where this operates in IPV4 and IPV6.
Tunnel mode
In tunnel mode, the communication happens
with the datagram with two gateways.
VIRTUAL PRIVATE NETWORKS
(VPN)
VPN is a virtual private network where the
communication happens through a private
network. The communication happens with
an internet connection. The communication
protocols are established using the tunneling
protocol.
VPN is of two types. They are remote access
and site to site access. In remote access, the
users can get the connection from their
location for adding the protection to the
company. In site to site, the connection is
established between networks of two
companies.
VPN uses two components for the
communication. They are terminators and
tunnel. Terminators are used for performing
the encryption and decryption services. It
can be a software or hardware for encrypting
and decrypting the data. The tunnel is used
for connecting the endpoint link
In general, VPN has three types. They are
Trusted VPN, Secure VPN and Hybrid VPN
Trusted VPN
This VPN is used for providing the security
and privacy of circuits based on the trust.
Secure VPN