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UNIT 2: Networks

OTHM LEVEL 3 FOUNDATION DIPLOMA IN INFORMATION TECHNOLOGY

Index

Questions Page No.

1. Understand networking principles. 2-6

1.1 Explain a computer network.

1.2 Differentiate between ‘client computers’

and ‘peer computers’ from network services

perspective.

1.3 Describe local area network (LAN) and

wide area network (WAN).

1.4 Describe the benefits and constraints of

different network topologies.

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2-3

3-5

5-6

2. Understand how network hardware and

software components are connected.

2.1 Explain how hardware, software and

addressing combine to support network

communications.

2.2 Describe potential issues with computer

networks.

2.3 Explain the steps required to set up and

test a simple local area network.

3. Understand the usage and security concerns

related to networking.

3.1 Evaluate the features and services

provided by a local and a wide area network.

3.2 Identify security issues related to

networking and how those security issues can

be minimized.

3.3 Explain steps to configure security on a

local area network.

7-12

7-8

8-9

9-12

12-16

12-13

13-14

14-16

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1.1 Explain a computer network?

The foundation of IT connectivity is computer networks. They are widely used and may contain

several various network forms. A computer network is a group of machines linked such that

knowledge is shared. Computer networks were the first manifestations from the 1960s, but they

have been a great success since half a century.

Computer networks are utilized for the knowledge exchange to perform a wide range of

activities.

Any of the topics utilized by the networks are:

• Text, recording, instant messaging and other communications.

• Share machines like printers, scanners and copiers.

• File sharing.

• Remote systems share information and running programmes

• Allocate easy access and maintenance by network users.

1.2 Differentiate between ‘client computers’ and ‘peer computers’ from network services

perspective?

The most significant differences are:

CLIENT COMPUTERS PEER COMPUTERS

1. Differentiated clients and servers are

available in the Client-Server

Network.

Clients and servers are not distinguished in

the Peer-to-Peer network.

The network Peer-to-Peer relies on

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2. The Network Client Servers concentrate on

the exchange of knowledge.

3. Centralized servers are used to store the

data in the Client-Server Network.

4. The Server can answer resources requested

by the Client on the Client Server Network.

5. The network of client-servers is costlier

than the network of peer-to-peer.

6. The network of the client-server is more

robust than the peer-to-peer network.

7. On both small and big networks, client-

server networks are utilized.

networking.

Each pair has its own data when in the Peer-

to-Peer Network.

Each node will both request and answer the

service when in the Peer-to-Peer network.

The Peer-to-Peer Network is less expensive

than the Client-Server Network.

Whether peer-to-peer network increases, the

number of peers is less constant.

Since the Peer-to-Peer Network is usually

suitable for smaller networks of less than 10

devices.

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1.3 Describe local area network and wide area network?

Local Area Networks (LAN)

The LAN is a computing network confined to one office, a single house, several buildings within

a campus, and so on. It is typically a single organization's privately managed and operated

network.

The picture below displays a tiny Local Area Network (LAN) network connecting to the

network.

One or more subnets may also be used in the Local Area Network.

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Wide Area Networks (WAN)

A WAN is made of several LANs and covers many regional areas. It is not possible for small

and medium-sized enterprisesto pull network cables from two offices situated 1000 kilometers

apart from each location in 2 separate nations. The networking options for wide area networks

are available by network service providers also known as Internet Service Providers.

The picture below displays the 2 LANs at two geographical locations linked to a large area

network through the Internet (WAN). LAN 1 in Chennai, India and LAN 2 in the Philippines is

based in Manila. Chennai-Manila is about 4,400 kilometers away. It is not possible for a SME to

draw cables between Chennai and Manila. It is almost unlikely for a SME. In order to link these

two offices, we usually use the facilities of an internet service provider.

1.4 Describe the benefits and constraints of different network topologies?

A topology of a network refers to the way nodes are linked in a network. The connectedness

determines how they interact. The advantages and drawbacks of each kind of network node

organisation. The advantages and limitations of various network topologies

Topology of buses

Advantages:

1. The handling and implementation is simple.

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2. Small networks are better adapted.

Drawbacks:

1. The duration of the cable is small. This reduces the number of linked stations.

2. Only for a small number of nodes will this network topology function effectively.

Topology of the ring

Benefits:

1. Both intermediate nodes proceed through the data exchanged between two nodes.

2. For the management of this topology, a central server is not needed.

Drawbacks:

1. The failure of a single network node will lead to a failure of the whole network.

2. Movement or modification to network nodes has an impact on the network's efficiency.

Topology of Mesh:

Benefits:

1. Data may be transferred from one node to several other nodes simultaneously in the

organisation of network nodes.

Drawbacks:

1. Many links do not serve a significant function, since each network node is linked to every

other node of the network. This results in certain network links becoming redundant.

Topology of stars:

Benefits:

1. The topology provides simple functioning because of its unified structure.

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2. It also ensures that all devices in the network are isolated.

Drawback:

The activity of the network relies on how the central hub works. Thus the central hub breakdown

contributes to the whole network failure.

2.1 Explain how hardware, software and addressing combine to support network

communications?

The way hardware, software and addressing combine to support network communications is

explained below:

• For the connection of computers and other peripheral devices to the network, either through

wireless or by a cable, a network adaptor known as a network interface card is needed.

• For direct connection of the computers and peripherals or through a switch or hub cable is

required in a non-wireless network.

• A hub is used for the connection of computers and peripherals to a cabled network using

topology for a star network.

• Switch used as a hub but the switch does not transmit to all linked ports. It uses the IP address

of the data packet to steer the information to the right computer.

• The Wireless Access Point means that printers, computers, etc., can be connected via radio

wave to a wired network and cannot be cabled unless they have a wireless NIC.

Software is a computer programme that allows you on your computer to do those basic tasks. It

guides the work of all computer peripherals that includes keyboard, mouse, hard disc, and

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display. The hardware could not be controlled without software. A software consists of two

maintypes: software framework and software implementation.

System software Types:

• Operating System (OS): A system software kernel that is first mounted on your machine for

the purpose of identifying and functioning apps and computers. As the first software layer, each

time a device is started up it will be loaded into the memory.

• System drivers: they provide life to computers and peripherals. Device drivers attach external

modules and add-ons to execute their planned tasks. The OS does not delegate tasks without the

pilot. A few examples of devices which require driving to work are the mouse, keyboard,

speakers and printer.

• Firmware: it is the running software that can be identified by the operating device in a ROM,

flash or EPROM memory chip. It directly handles and monitors all the work of one hardware.

Without switching semiconductor chips, firmware can be quickly updated.

• Translators of programming languages: Intermediate programming for high level source-

language translation into machine-language code. Language translators are very common among

compilers, assemblers, and interpreters. These are used to convert software codes completely or

to translate them one by one.

• Utilities: It is designed for machine diagnosis and repair. They may vary from the key data

protection to defragmentation of the disc drive.

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2.2Describe potential issues with computer networks?

Performance of network is the response time that is

how easily you can send a message or how soon you can get a document.

Different factors may influence the efficiency of a computer network:

Number of network units.

Number of failures in transmission.

Network transport category.

Network latency.

Transmission media bandwidth.

One or a combination of these factors may impact any network.

Bandwidth:Bandwidth is a quantity of data which can be transferred over a specified period by t

he medium. There is a separate bandwidth for each transmitting medium.

Different forms of bandwidth characteristics of network traffic typically vary.

Latency:

Latency in the network is a metric of how long a message is needed to move through a network f

rom one system to another. A low latency network has few communication delays, while a high l

atency network has more delays. The time it takes to relay data over a network, the more delays a

re.The number of network devices and the form of communication system are influenced by the l

atency.

A hub-based network normally has more latency than a switch-

based network, so all messages are sent from hubs to all networks. Switch-

based networks send messages to the desired beneficiary only.The more computers attached to a

network, the more relevant the option of the media. Wi-

Fi is inherently less trafficable than the fiber-optical network, which carries less traffic.

Transmission errors:

There would inevitably be moments where machines are simultaneously trying to connect. Their

signals clash and the transmission is not effective. It's as how two persons talk together at the sa

me time — no one will understand what the other person said clearly.

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A conflict happens when two systems in a network want to connect on the same channel concurr

ently.The more computers in the network the more likely a crash is, the greater the time it takes f

or a message to be sent.

2.3 Explain the steps required to set up and test a simple local area network?

A LAN, or a regional network, is only a little, far smaller than the internet. In other words, it

comprises of just a few devices linked. You may like a LAN, so that you can exchange data,

transfer images and music to other machines, link easily to a printer and play games with some

customers with a good old-fashioned LAN band.

1. Gather the equipment

First, to set up your LAN, you need the right tools. Including

Path router.

For each system to be linked, Ethernet cables are required.

Devices

Computer.

Broadband, router and modem connectivity.

Start by connecting to and enabling the network router. Whether it is completely fresh, obey

the instructions in the package and it's ready to be plugged in.

First connect the Computer

You would have the machine to link to the router if the router is new. This can be done with the

help of the Ethernet cable. You should be prompted immediately by a Windows Personal

Computer with a first link installation wizard, but it can be found in the Network and Sharing

Center in the control panel's settings section. On a Mac, the preferences of the system may

include this configuration.

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Wireless Internet access Set Up

The automated settings wizard can carry you through the procedure step by step so that you can

get the internet up and running. After you have the Wi-Fi feature, you should still be able to link

your computers to Ethernet cables on the internet.

Web Connection

The notion of a LAN is to link various devices together - but it is now when you need to set up,

whether you want to provide internet connectivity, too. You should be able to link and go if you

already have a functioning router and high band connectivity.

In the other side, if you setup a new router and / or web link, your broadband company or router

vendor would have to obey the directions provided to you. In this case, the router and modem

must be plugged into the main telephone line of your home utilizing the WAN-port router.

Attach your other equipment

If it is Wi-Fi or an Ethernet cable that you attach your devices to the LAN, it is now time to hook

up everything. It involves other computers, notebooks, smartphones, tablets, TV screen, game

machines, sticks, all of which will require online access.

Get sharing

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One of the beauty of a LAN is that services, such as laptops, files and media can be shared

through it. With Windows PCs, setup of a 'Home group' is super simple.

Go to the check box, then click on network and the Internet, then click on Home group,

then choose 'Build a home group.' Windows will lead through the home group

configuration wizard and a password is sent for connecting to it that other devices require.

You may also set up different user profiles on your current LAN.

3.1 Evaluate the features and services provided by a local and a wide area network?

The main features of LAN are:

Network size is restricted to just a few kilometers in a particular metropolitan region at

the moment. It can be between 100 Mbps and 1000 Mbps.

In general, only uses one kind of medium is used by LAN, typically coaxial cables of

Category 5.

The Local Area Network is characterized by its topologies by other networks. Thevarious

topologies are Bus, loop, star and mesh.

The Local Area Network is normally limited in number of computers. LANs are

constrained in other words, scalable.

The most frequent LAN is IEEE 802.3 or Ethernet. In conjunction with a click, you use a

wired medium. Coaxial cables were first used to communicate.

The characteristics of WAN are WAN

• WANs have a high capability, are intrinsically flexible and link several computers over a wide

region.

• Allow regional capital to be shared.

• Uplinks to the Internet for LANs and MAN connections are given.

• National carriers such as cellular networks, network operators, television services, satellites,

etc. have communication connections.

• In general, the transmission rate and the latency of dissemination are poor, meaning the pace of

contact is low.

• In addition, the bit error rate is higher.

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Examples of WAN are:

• World Internet

• 4G Broadband Services Active

• A currency transport network.

3.2Identify security issues related to networking and how those security issues can be

minimized?

The below are the five most important security concerns relating to networking and how to

mitigate security problems.

1. Code Injection.

Often hackers may use bugs for embedding malicious code in applications. Many times a user's

text input area, as with a username where SQL is entered in what's called a SQL injection attack,

is a weakness. The vulnerability can be contained in a text input field. This method of attack may

be responsible for compromised keys, destruction of files, or lack of server power.

There are two methods to stop injecting code: to avoid insecure code and to process content.

2. Data Breech.

Software infringement costs are well known. Sometimes due to vulnerability credentials, neverth

eless, device misconfiguration, missing hardware or malware are commonly caused.

Prevention of data breaches calls for a variety of common measures. Transactions and site

transport should be Secure Socket Layer encrypted, permissions for each user community be

carefully fixed and servers are screened. Employees ought to be qualified to prevent phishing

threats and ensure proper security for passwords.

3. Infection of Malware

Many companies know that e-mail spam is still the key vector of malware attacks at any stage,

however, many people do not realize that it poses a risk to defense.

Since malware comes from a number of sites, a number of tools to avoid infection are required.

A robust email infrastructure and malware and vulnerability scans are required for filtering. As

infringements sometimes caused by malware, staff education is essential to safeguard companies

against malware.

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A malware-infected computer or machine must be completely scrubbed, so that secret parts of

the code are identified and all the contaminated data are deleted until they reproduce. This is

virtually not possible, so an efficient automated tool is needed.

4. Distributed Denial of Service Attack

An assault by Distributed Denial of service usually entails the use of a hacker to overwhelm the

traffictarget on a group of computers.

A research by NETSCAPE Arbor indicated that in 2017 7.5 million DDoS attacks have occurred,

and so many IT services providers are far more common than many people know. One of the

worse consequences of a corporate DDoS assault is that the corporation is hit only by the same

service provider, server, or even network infrastructure without being attacked.

If the company is involved in a DDoS assault, implement a disaster response strategy and explain

the damage to staff and consumers. A detection technique such as a WAF is used to shut the

saturated protocol, which is probably reused when attackers adapt their tactics.

5. Insiders without Malice

It is not comfortable, but normal to take careful account of this last challenge, as the 2017 CERT

study from the U.S. State of Cybercrime indicates that insiders conduct one of five assaults.

The prevention of insider assaults involves mostly restricting access by a hostile insider. This

ensures that the logical access control policies are set to follow the least privilege standard and

the network is monitored by audit and transaction records. A solution like the custom malicious

activity detector from Liquid Web prevents threats both internally and externally.

If a disruptive insider assault is found, access rights for the insider should be removed

automatically. In order to avoid the conduct of further activity that could damage the company,

such as the sale of stolen records, the police should be called.

3.3Explain steps to configure security on a local area network?

Any of the information collected in the University electronically is economical, personal and

medical sensitive information, as well as private information. Unauthorized distribution or data

access is immoral and potentially unconstitutional in connection with the University network. If

it is deliberately or unintentionally violated, personal responsibility can occur.

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Protection on a local zone network is configured through several steps:

Step 1: Simplify and never share a strong password

Your password is the secret to network entry. You can pick a good one to minimize the

likelihood that a programme or other deviates your password.

Step 2: Nobody is allowed to use your user account.

The account used by you represents all the computer tools to be used by you directly. By

allowing someone use services with which they might not be able to utilize their user account,

you help them to access theresources. Ultimately, everything they can do is the duty.

Step 3: Use Important Files network drives

The files containing or vital to the job sensitive details should be saved on a network disc, but

only as long as they are necessary. These drives are normally higher in the above "F:\" alphabet.

The drives of the network are used because of following:

Security: Someone with physical access to a device will access the data saved on their local

computer drives — A:\ via E:\ in one way or another.

• Protection of files: If a device fails, all data on local discs will be destroyed. The overnight

backup of files saved on the network drives. In the case that data is destroyed owing to disasters,

the chances of data being recovered in a comparatively new state are much higher.

Step 4: Locate your computer on the day you leave your desk

If you abandon your desktop for many minutes, leave your screen on and activated, the world's

stronger password would not apply. You can plan your work area when you are at your desk, so

that casual guests cannot see desktop. This will mitigate a great deal of inadvertent access to

sensitive or private data.

Step 5: Shut your computer off on the day

Switch off the machine at night before you reach the workplace. A machine not affected by

threats by other machines will not be affected or hacked.

Step 6: Use Sensitive Data Exchange and View Encryption

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To see websites with personal data you can still use cryptography. If the domain address starts

with "https," you will determine if the website uses encryption.

Step 7: Do not install unauthorized softwares

For installation on university computers only programmes in Start, then USM Apps and Install

have been accepted. Do not install Internet free applications.

Step 8: Thinkwisely Before Opening Email Attachments

Be wary of emails that you didn't intend to get, even though it seems like anyone you trust. If

somebody you meet happens to have it, email him before opening it to ensure that he intends to

give you the attachment.

Step 9: Plan your computer's antivirus scan

Your machine normally sits idle in your office at this stage. Now is a great moment to run the

machine for an anti-virus check. This will operate during the locking of your screen. Please

report them to the Helpdesk if any viruses are found.

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References

https://www.fieldengineer.com/blogs/what-is-a-computer-network

https://www.jigsawacademy.com/blogs/cyber-security/difference-between-peer-to-peer-and-

client-server/

https://www.omnisecu.com/basic-networking/lan-and-wan-local-area-network-and-wide-area-

network.php

http://nafi.yolasite.com/resources/Advantages%20and%20Disadvantages%20of%20Different%2

0Network%20Topologies.pdf

https://teachcomputerscience.com/computer-networks/

https://fcit.usf.edu/network/chap4/chap4.htm

https://www.bbc.co.uk/bitesize/guides/zvspfcw/revision/8

https://www.fingent.com/blog/a-detailed-guide-to-types-of-software-applications/

https://www.fieldengineer.com/blogs/5-steps-to-a-successful-lan-implementation

https://www.tutorialspoint.com/Wide-Area-Network-WAN

https://www.liquidweb.com/blog/five-common-web-security-problems/

https://usm.maine.edu/computing/10-steps-data-and-network-security