Comprehensive Network Security Report: Layers, Protocols, and Analysis

This report provides an overview of network security, focusing on the application, internet, and physical layers. The application layer is discussed in terms of user interaction with internet services, client-server and peer-to-peer architectures, and protocols. The internet layer introduces the Address Resolution Protocol (ARP), including its commands and functionality. The physical layer covers data flow (simplex, half-duplex, full-duplex), Manchester encoding, and multiplexing techniques (TDM, FDM, WDM), as well as various transmission media such as coaxial cables, optical cables, and wireless technologies. The report aims to explain the interconnection of computers and devices in a network, and how data is transmitted and secured across different layers.

NETWORK AND SECURITY
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Introduction
Network security comprises of any activity, practices and policy which is done or
adopted for the main purpose of managing and controlling unauthorized modification, misuse,
access, and prohibition of the network and the resources which can be accessed through the
network. The accessibility to the network of the computer and the access of the resources is
controlled and managed by the network administrator. The user of the network therefore is given
a user Identification and password or rather, any other authentication method to access the
resources of the network.
The topic network security have several subtopics but to this case, we are only discussing
on the 3 topic which includes the application layer, the internet layer and the physical layer of the
network security.
Application Layer
Under this topic, we are introduced to layer 5 which is application layer. Here the
application layer is said to have given the users the opportunity to interact with many devices and
services over the internet using the local network. Some of the services which are accessed
through the internet services includes the following: Google maps. Facebook, Google search
engines and many more.
User applications give us the ability to interact with thousands of services and devices on
the Internet and on our local network. These applications are enabled though their ability to use
networks.
By the use of the local network, the access to file sharing services is possible, this
includes access to printers and other devices.
There are a number of the application layer architecture categories. This includes the
following;
The client – server architecture; here the client requests services from the server. The user
of the application is the client. Server is taken as the provider of services and the client as the
consumer of the services provided by the server.

The peer to peer architecture; here the client and the server have the same
interchangeable functions since they can both provide the client server functionality. The both
machines can be used for sharing information.
Other categories of architecture includes the host based architecture and the cloud
architecture.
The description of how the network application layer works was also discussed taking
some common example of application layers such as the web browser and the FTP client into
consideration. Then the network protocols and their roles was also discussed.
The Internet layer
Under this topic, ARP which is Address Resolution Protocol is introduced. This is the
Address which defines the machine MAC address while on the LAN. Some of the ARP
commands are also discussed. Taking some of the examples of the commands are;
The command to observe the contents of the ARP cache is arp – a
In order to delete an entry, the command arp –d ip address is used, where you replace the
name ip address with the real address.
In order to make deletion to all the entries, use command arp – d*.
A demonstration of the ARP in linux was also done, then the previous week discussion
on data link layer was also reviewed.
The main role of the network layer is to deliver the network from the host to another host.
For the addressing to take place, the IP address must be addressed, ipv4 and ipv6 are the two
types of the IP address.
Physical layer
Physical layer can be explained as the interconnection between the computers and other
devices in a network. The most crucial components under discussion here includes; data flow,
transmission media, Manchester encoding, analog to digital data and the multiplexing.

There are two major types of data under consideration. This includes the digital data and
analog data.
Digital computers and devices always stores data in digital formats in programs, text files
and other digital forms. Analog data such as the voice takes an endless number of level, though
for this to be transmitted, it can be converted into digital and transmitted digitally.
The data flow includes the half duplex, full duplex and the simplex. The simplex data
flow system onlt sends information on one path. The half duplex data flow system data to flow in
both the paths, but now only one direction data can flow, each at a time. Full duplex is free and
permits flow of data in both directions and this is permitted concurrently.
The topic also demonstrated how the Manchester encoding work where the
representation od the binary values are done by the transition of the bits in periods.
Multiplexing is utilized in the process of division of the channels of communication in
order for the channels to sent multiple data each at a time. The methods of multiplexing includes
the following; Time division multiplexing also abbreviated as TDM, The frequency division
multiplexing , FDM and the Wavelength division multiplexing named WDM
Transmission media: these are the physical components with can transfer data from one
place to another. In networking and communication frameworks, the transmission media
includes the following; The coaxial cable, the satellite microwave, the optical cable, Shielded
twisted pair, the infrared, the unshielded twisted pair, and the terrestrials microwave.