bryan ye, year 9 ipt, mr simmonds, 2011 communications assessment task

8/2/2019 Bryan Ye, Year 9 IPT, Mr Simmonds, 2011 Communications Assessment Task

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Bryan Ye, Mr Simmonds, Year 9 IPT 1

2011 Communications Assessment Task

1. Describe in detail the operation of a web server and mail server.

A server is an electronic computer used to serve requests of other entities which are clients.

They are dedicated to running services for their clients which are other users in the same

network. They are designed to have a decent amount of storage and require other hardware

such as a router, network card etc. Software that includes an operating system, application

software and device drivers are also needed in ability to connect to their clients and carry

out their services. There are many types of servers that are used for many different

purposes which include web servers and mail servers which are both very common in theinformation age.

A mail server is a storage device which acts as a rendezvous for the user to send data to the

recipient. It is generally dedicated to help the user send electronic emails to the recipient. It

is also used to store e-mails and help the recipient receive emails. To be able to do this, a

mail server requires internet connection and a storage device. As stated before, the storage

device acts as a rendezvous for the user to send data to the recipient. This happens by the

user sending an e-mail to the mail server which then sends the data to the recipient. This is

the reason the user does not need to be connected to the recipient in order to receive data;

both parties are connected to the mail server via internet connection.

Mail servers also use SMTP (Simple Mail Transfer Protocol) which does various things to

help the e-mail reach the recipient. When an e-mail is being sent, all e-mails contain two

broad components, an envelope and a contents component. The envelope, which contains

the address and other information required to get to the recipient is read and thoroughly

checked by SMTP. The contents component contains the actual message with other header

fields that are needed to tell SMTP the sender, receiver, date/time, subject and the

relationship of the message to other related messages. When an e-mail is sent, it is

transmitted to an SMTP server where SMTP checks the envelope and the contents

components of the e-mail. After examining thoroughly and finding the destination, it is then

sent to the recipient’s SMTP server.




Along with SMTP, another application level protocol is also needed to be used. This will

either be POP (Post Office Protocol) or IMAP (Internet Message Access Protocol). The POP or

IMAP server only does the delivery and organisation part of the transmission. After the

message is sent to an SMTP server, the message is then given to a POP or IMAP server which

places the mail into the recipient’s inbox, much like the delivery guy placing a mail inside

your mailbox after the post office has given you the mail. POP or IMAP also asks for

authentication details when the user attempts to view his/her e-mails. This is where the e-

mails are sent from the POP or IMAP server to the recipient.

Transmission of data between a user and the recipient of a mail server

A web server is a server that helps transmit data that can be accessed through the internet

such as web pages. The most common use of web servers is to host websites although they

are also used by businesses for other purposes such as enterprise software. Web servers

require a decent amount of storage space to store web pages, data, information and other

important hardware required to carry out its purpose such as a router. This means that the

web server requires internet connection. One of the main reasons for this is that a web

server needs to upload data or else nobody else can view it. Software is also required for the

server to run and process data.

For a client to view a web page, they require a web browser or web crawler which begins




the operation of requesting HTML documents. The HTML documents are then retrieved

using the HTTP GET command and URL (Universal Resource Locater) to retrieve entire

documents. The URL is simply an address which tells HTTP GET where to retrieve data from.

Inside the HTML documents there may be images, videos or any other types of files that can

be retrieved. Users may also use HTTP HEAD to simply retrieve the header of the HTTP

documents or HTTP POST to send data to the web server.

2. Outline the operation of a home wireless network (include all Information

Technology and protocols used). Discuss the advantages and disadvantages, giving

examples of each to justify your answer.

A home wireless network is a LAN (Local Area Network) which is enclosed in a way that you

require to be in vicinity of the network to use. Most home wireless networks have a physical

star network topology where there is one central node and other nodes that connect to the

central node. Other details are also needed to use a home wireless network such as

authentication and an electronic device which can detect the digital signals from the

network. They all come in different data rates, frequencies and bandwidths depending on

your Internet Service Provider, internet plan, location, router and other factors. Home

wireless networks are used for communication between electronic devices such as

computers, iPods, scanners etc.

The most common use for home wireless networks is connecting personal computers to the

internet although they are not limited to this. Having a home wireless network means that

the devices on the same network can communicate quickly without any problems. Having a

home wireless network means that you can have protected internet which does not require

wires and as a result of this new level of technology, they are expensive, fragile and you may

offer some of your internet speed. They are also easily played around with especially by

professional hackers who can easily bypass the authentication details. It is easy to find out

who is usually your internet though, because people are only allowed to use your network if

they are in vicinity. They typically connect electronic devices using point to point links.

A home wireless network requires a lot of mandatory hardware unlike computers where

you can throw away an SSD and replace it with a hard drive, or throw away a few USB ports




and it will still be fine. A home wireless network is not like this. It requires electricity and

stable internet connection such as ADSL. Dial up will not work very well with a wireless

network. Another piece of mandatory hardware is a WAP (Wireless access point) and

wireless adapter or NIC (Network interface card). These two pieces of hardware are used to

connect your personal device to the internet.

The WAP is typically located on the router. It is used as the central node of a wireless

network to broadcast to other wireless nodes in vicinity (located on the wireless adapter or

NIC). Because the WAP is a central access point for anything within vicinity, it is quite easy to

tamper with it. This is why the protocols WEP (Wired Equivalent Privacy), WPA (Wi-Fi

Protected Access) and WPA2 (Wi-Fi Protected Access 2) were created. WEP was a protocol

that only offered password protection. These protocols can easily counter unpolished

strategies to gain unauthorised access. WEP was the first protocol introduced to defend

wireless network but only introduced password protection. WPA and WPA2 were then later

created. These showed much stronger protection because they encrypted as well as used

password protection.

The wireless adapter or NIC act as modems to constantly modulate and demodulate data

when needed. When connecting to other wireless devices within the network, the analogue

that the wireless adapter or NIC has transmitted is detected by the router and redirected to

the other wireless device. Because of the fast communication between the central node and

other nodes, full duplex communication is achieved.




Transmission of data from central node to other wireless nodes showing devices which

contain the nodes

Home wireless networks operate within the Ethernet protocol which is at the IPT

transmission level including OSI data link layer 2 and OSI physical layer 1. A MAC (Media

Access Controller) address of both the sender and recipient is required for the nodes to

understand the destination. The wireless adapter, NIC and WAP all have a unique 6 byte

MAC address. MAC addresses act as envelopes which tell the nodes where the Ethernet

packets are going. A typical MAC address would look like this 00-00-E2-66-E3-CC. A final 4-

byte CRC (Cyclic Redundancy Check) is also used at the end of transmission to check for any

errors in transmission. It is possible for two nodes to transmit a frame at the same time but

only if they are on different physical transmission line. If they share the physical

transmission line then a data collision will definitely occur and both frames will be

corrupted. A system called CSMA/CD (Carrier Sense Multiple Access with Collision

Detection) is used to deal with these collisions. This is only the case for hubs though as

modern day Ethernet networks use switches where two nodes exist on each physical line.

There are many advantages to home wireless networks and also many disadvantages.




Ultimately, the advantages easily outweigh the disadvantages.

Advantages

Ease of access

No wires that cause tripping hazards

Allows devices such as iPods who cannot connect to the internet using an Ethernet

cable to access the internet

Multiple connections to the internet can be achieved at the same time without

spending time setting it up

Implementation is cheaper

Unreachable areas (across a river, mountains, rural areas) may still access internet

Easier to set up (ideal for temporary networks)

Disadvantages

Changing nature of work

Speed is lowered by a tiny bit

Networks can be interrupted [walls (blocking), microwave oven (interference), far

distance (attenuation)]

Less secure

More complex to configure

As you can see, it is a good trade-off between the advantages and disadvantages as you will

almost never encounter any of the disadvantages in the modern day.

3. With reference to Question 2, describe in detail the communication between your

Wireless laptop at home and the STHS intranet.

While using the STHS intranet with your wireless laptop within the school vicinity, the STHS

intranet will be acting as an intranet. However, if you are using the intranet from home,

which is outside the vicinity of the school, it will be acting an extranet. An intranet is

basically a private network that is maintained by an organisation and in this case, Sydney

Technical High School. An extranet is basically using an intranet outside the organisation.




The Sydney Technical High School intranet has dedicated leased lines for traffic which

means that there will be high-speed

For a user to enter the STHS intranet, they will need to enter authentication details. These

details are given by the school to students, teachers and parents. Of course each of these

classes will have different authorities to the school network. If the credentials are incorrect

or invalid, an error message will pop up and say 401 – Unauthorized: Access is denied due to

invalid credentials. This means that you are forbidden to access the school network and that

you will either need to either reset your password because it has expired or ask the TSO

(Technical Support Officer) to help reset your password.

Error message if credentials are incorrect multiple times

Once you are inside the school intranet, you will be entering a VPN (Virtual Private

Network). A VPN is a network that requires a public telecommunication infrastructure andin STHS’ case, it’s the internet. The internet is used to communicate from the central

organizational network to clients that are connected to it. This network has a physical star

topology and a logical ring topology while using the intranet via the school vicinity but if you

are using the STHS intranet as an extranet, it will simply be a physical star topology. The

advantage of this is that people are able to connect to the STHS intranet and disconnect

without disturbing any of the other users.




Relationship between clients and servers in a Virtual Private Network

TCP/IP (Transmission Control Protocol and Internet Protocol) is also extremely important to

using the extranet. If a user wants to receive files from the STHS intranet, these 2 protocols

are vital and they are automatically installed into the routing software of every router. TCP

(Transmission Control Protocol) is the main delivery system of transmission. A user would

first request a file such as a textbook from the school intranet. The school intranet would

use TCP as a delivery system to send the stream of bytes to the user. IP (Internet Protocol) is

then used to direct the stream of bytes that TCP are sending to the user using the IP Address

which is the address that every computer has. An IP address is typically a numerical label

applied to each computer and is a 32-bit number. They would typically look like this

172.16.254.1. In a physical form, TCP would be the delivery guy, IP would be a map and the

IP address would be the address located on the mail.

4. Communications have greatly changed the nature of the work place. In relation to

the following headings, briefly describe using examples on each as to how the

nature of work has changed.

a) Power and control

As technology is being introduced, power and control in the workplace has changed and will

continue to change. The way a worker communicates with his employer is one vast change




in the working community. In the past, to contact your employer you could not directly

contact the employer because that would mean physically walking into his/her room.

Having every employee physically walking into his/her room would hinder his work. The way

communication worked was the worker would give his message to someone who had more

privileges then him/her and then they would pass the message on so someone who had

more privileges than them and so on. This means if there was something personal, there

would be no privacy. In the current day, you can contact your employer by sending a private

message that they will respond to after an appropriate amount of time. The most common

way for this to occur is e-mailing.

b) Ethics

Ethics is a big issue as technology is advancing especially with the internet. The internet

gives us a wide choice of information and how you can obtain that information. Different

people will have different levels of access. It is common for humans to get greedy and want

to obtain that information when they don’t have access to it.

The internet is full of scams used to obtain money and details. Internet fraud comes in many

different forms. It is common for bots to send e-mails in attempt for an uninformed person’s

credit card or banking details. This is an extremely serious crime much like stealing except

that internet fraud is extremely common. This is one of the ways people can get

unauthorised access, by preying on people who are beginning to use the internet and

manipulating them.

Another ethical issue is piracy. This is also extremely common and serious. People can gain

software or media which costs money by simply downloading a crack or key generator.

Many people also commit piracy without knowing what they are doing. For example,

downloading a simple song is committing piracy.

While on the internet, people are inconsiderate and because it is almost untraceable and

that there are so many people abusing the loopholes in the internet, it cannot be dealt with

as of now. If someone was to physically steal a movie from a shop, they can be easily caught

but if there were hundreds of thousands of people stealing movies, it won’t be possible to




stop them. This is the case because of the high bandwidth.

c) Interpersonal relationships

When you hear relationships, you will typically think about face to face communication. This

may have been the only way of communication a few hundred years ago. This has been

changing through fax, telephones and finally we are at the information age where we have

instant messaging, e-mailing, calling, etc. In the past people would attempt to keep close by

face to face communication where they can interact freely.

The nature of this has changed as people have learnt that there is no need to preserve a

relationship by face to face communication and that you can easily keep a relationship from

a long distance. As technology has advanced, it has made it easier and easier for us to keep

up to date, communicate with relatives across the globe and ultimately has made face to

face communication more and more unneeded.

Instead of physically giving invitations for a party, you would text, e-mail, call or make a

status on a social networking website such as Facebook. Although for your everyday needs

these forms communications can satisfy your needs, it definitely is not a healthy way of

communication if it is repeated. Face to face communication and physical contact with

other humans is still needed because of how our minds work. It is also much harder to

interpret information online especially sarcasm or puns. This is because body language and

facial expressions are not included.

Businesses have also set themselves to other communication systems such as

teleconferencing. This brings in many advantages such as cost reduction with travel and

accommodation and the fact that it is easy to setup and schedule. It is also much easier to

communicate regularly with everybody. However, there are also disadvantages to this

information system as it is much harder to develop interpersonal relationships since you are

not physically present. Maintaining concentration during extended phone calls is also

extremely difficult and as listed before, body language and facial expressions are not

present.




d) Work and employment issues

Communications has affected employment in many ways. In the past you would have to

physically show up to work and do your job as the cycle repeats. If you were sick, you could

skip work. In the modern day, it is easy to communicate and work from home meaning that

even if you were sick, you would still have to work. Because being able to work from home

is so easy, people who aren’t able to physically attend the workplace can work from home.

It is also much easier to monitor your employees to make sure that they are doing their

work. There is so much you can record and check for example, telephone calls, e-mails,

internet history. This may sound like a good idea at first where the employer can completely

see what the employer is doing so that he is doing the right but that is not the case. This can

easily lead to a violation of privacy and can also create bad relationships between the

worker and employer. The worker will also be under a lot of stress knowing that the

employer will know exactly what he is doing.

There is also a variety of different types of data in the information age. In the past you

would have to send a paper resume and physically go to an interview. IN the modern day

world you don’t have to. There is more data than just words; you could easily make a video

resume which contains a high amount of propaganda using special effects etc. to get

yourself a job without even having an interview.

e) Current and Emerging Trends in Communication

In the past everything was done by paper and recorded on paper. This is definitely not the

case in the modern day world. The trend of doing everything digitally is emerging. This is

evidently happening in Sydney Technical High School as books are being scrapped and

laptops are being introduced. Textbooks are even being scrapped and placed inside laptops.

This current trend can affect us in different ways. It is much easier to type than write every

letter on a paper and using OneNote to organise your work is much easier than using a

book. However, laptops definitely result in distraction and can also lead to poor eyesight.

Communication has lead us to go from writing, to pressing keys and finally to touching a

screen. Devices which have touch screens are becoming more and trendier as we speak.




People of all ages are starting to use touch screens, especially teenagers. It is easy to say

that 80% of all teenagers have some sort of device with a multi touch system. These touch

screen devices also include other special features which are also emerging trends. iPhones

for example include a camera, wireless technology, music player and a phone system. It is

also a small device that can fit inside your pockets, which is also an emerging trend. Big old

telephones becoming small mobile phones are one example of this.

The way people acquire information has also changed. In the past libraries were much more

common than today. They were the resource to all information. Today all we need to do is

type something in a search engine and we would have what we need. Google, the most

popular search engine is the 3rd

most popular website in the World Wide Web.

Social networking is also an extremely popular hobby for teenagers as communications

using the internet has been introduced. There are hundreds of social networking websites

that people regularly use such as Facebook, twitter, blogger and formspring. The most

popular website in the world is Facebook which evidently shows that it is a current trend

although it is extremely recent. Facebook has climbed its popularity extremely quickly

5. Australians have the reputation of taking up new technology very quickly; the use

of Smartphones is one such example. Explain the technology behind that allows

Smartphones to carry out a multitude of functions.

Smartphones are a current and emerging trend in the information age. They are a high-end

mobile phone which has a high amount of features. It is also built on a mobile computing

platform which means that it includes features that mobiles and computers have. These

features include high resolution screen, internet browsing, portable media playing, digital

camera and a GPS navigation unit and other applications such as mail, weather, calendar

etc. One of the most significant features that a smartphone has and other phones don’t

have is a multi-touch system. They are also very popular because of their neat design and

their portability. Smartphones use more advanced mobile operating systems than regular

mobiles. Some common ones are Apple’s iOS, Google’s Android and Microsoft’s Windows

Mobile.

The high resolution of smartphones compared to other phones is one of the several




significant advantages that they have. One of the main reasons that a smartphone has high

resolution is because they have an LCD screen. LCD screens have a number of advantages

including reduced radiation, cost effective, energy efficient, lighter weight, fewer harmful

chemicals and most important of all, higher resolution. Because of their high resolution,

smartphones are allowed to have increased detail in videos and photos which is a huge

advantage for phones. Imagine watching a YouTube video on a regular old phone. It would

not be very pleasing. There is also a reduction in video noise when you watch a video. The

noise of a video can increase the file size and at the same time decreasing the quality which

is definitely something that you want. This also allows for the user to play games that

require good graphics without losing any of the quality. However, there are disadvantages

of having high resolution. The smartphone would need higher processing requirements and

larger disk requirements to hold all of the files that the phone can record or take.

Internet browsing is another feature that smartphones have. The technology behind

internet browsing is simply having a wireless adapter. A wireless adapter allows

smartphones to connect to a WAP (Wireless Access Point) of a router and access the

internet. Internet browsing is an extremely efficient feature especially in this current age

where social networking is the most popular hobby among young people. Internet browsingalso opens up many other advantages such as RSS feeds which allows you to keep up with

news or specifically, interesting news. You can also use the internet for researching which is

one of the most significant advantages of internet browsing. There is no need to physically

go to a library and borrow a book when you can simply touch the screen.

Portable media playing is another feature that all smartphones are capable of. There are

several technologies behind being able to carry this out for example, storage devices. A

smartphone would need a decent amount of storage to be able to hold all the songs as they

are around 5 megabytes each. Also, along with songs they must also be able to play videos,

store pictures and be able to include applications. Most smartphones will have around 20-

40 gigabytes to be able to hold the files. For example, Apple iPhones come in 16 gigabytes,

32 gigabytes and 64 gigabytes. A 40 gigabyte hard disk will generally allow you to play up to

160 hours of video, up to 10,000 songs and hundreds of thousands of pictures. The

operating system of a smartphone is also a significant factor for playing and viewing these




files. There are many different file types that can be played on smartphones. The main types

of files that are viewed and played on smartphones are typically wmv, jpeg, mpeg, mp3, avi

and dvr-ms. The operating system is the key to being able to play these files. It organises

and controls the hardware and software so that it is able to behave in a certain way which is

able to decode these files.

There is also a digital camera installed into each smartphone. It is a remarkable feature that

was not installed into compact devices until recently. Digital cameras, like CDs, DVDs, MP3s

and other electronics are built around changing analogue data into digital data. Digital

cameras focus the light from what is in front of it onto a semiconductor and creates a digital

image. The digital image is then saved onto the hard disk that is inside the digital camera.

Digital cameras are much better and work differently than their predecessor, conventional

cameras. Conventional cameras depend entirely on mechanical and chemical processes and

have no connection with digital data, not even electricity. They also store data differently

from digital data. There is also a great improvement in megapixels from conventional

cameras into digital cameras.

A GPS (Global Position System) navigational device is a useful tool that is installed into

smartphones. It is able to pinpoint the location of where you are on the Earth from

anywhere on the Earth. The main technology that a GPS uses is the 27 satellites that orbit

the Earth. These satellites are extremely significant to the GPS and without them there

would be no that they could operate. 24 satellites are always operating and there are 3

extra satellites in case of a failure. These satellites were made by the military but were soon

opened up for everybody else. The GPS is a simple device that acts using a mathematical

technique used in geometry called trilateration. It basically locates four or more of the

satellites and then measures the distance from you to each of the satellites. However, it is

common for up to 8 satellites to be within range of the GPS at any time. It calculates the

distance by measuring the time it takes for each signal to reach the device. This is only able

to be calculated because the satellites send signals at constant speed.




Smartphones are also able to install third party software called applications. These

applications can be used for many different reasons such as entertainment, business or

personal benefits. There are many applications that can be downloaded and installed by

the user in each of these categories. Such as for entertainment there would be games,

for business there would be stocks and for personal benefit there could be a converter.

6. Other than E-mail and Social networking applications, discuss how other

applications/appliances have changed the way we communicate socially and

conduct business?

E-mails have been a great new trend in the 21st

century ever since they were introduced along with

other social networking applications such as Windows Live Messenger. However, these are not the

only communications technologies that have affected our lives greatly. There has been a great deal

of different communications ranging from Fax all the way to E-commerce that has made our life

easier and faster. Not only have these communications affected our personal social lives but it has

also affected the way businesses are conducted.

Fax (short for facsimile) is an extremely old way of communication that was invented in 1843 and is

still used in the modern day although not as much. Fax is a quick and efficient way to send scanned

text and images via PSTN. Fax works by scanning a printed document, converting it into a bitmap file

and sends it via PSTN using a telephone number which is connected to an output device as electrical




signals. The recipient’s fax machine then prints a paper copy. Fax has changed businesses in many

ways. Imagine running a business but being unable to send any documents to your client. Fax saves

enormous amounts of times in the business and allows them to be more flexible with their time and

costs. As an addition to Fax’s utilities, the recipient also is not required to do any work except. This

saves a lot of time as you can imagine walking to a collection box or being physically handed the

paperwork instead of having the paper come out of a machine. Fax has also gained more utilities

when internet fax was invented. These advantages include unneeded hardware and software, no

extra telephone line, paperless communication, simultaneous sending and receiving, reduction in

phone costs and the ability to send faxes from anywhere with internet connection. As you can see,

these advantages show a clear advantage in cutting costs and a decent advantage in utilities.

Telephones have changed our lives socially and in the business. Keeping in touch with friends and

colleagues have been much easier ever since telephone has been introduced. The requirement of

physical contact to keep in touch was discarded ever since telephones came out. It is not easy to

keep in touch with your friends simply by calling them over the phone. This full duplex

communication system has also affected business in many ways. New ways of business are opened

such as advertising via telemarketing and calling up clients for work (such as architects). Telephones

also bring in a half-duplex form of communication that is used around the workplace called voice

mail. This is used because full duplex communication while in the work place is very distracting. Fax

would be used for this purpose in the past but tone could not be provided via fax. This is why voice

mail has a clear advantage over fax. Telephones then introduced mobile phones, a smaller version of

a telephone that you could fit in your pocket. This is an extremely versatile that can be used for

many different purposes in the modern day. They include many utilities such as camera, multi-touch,

voice-mail, text, wireless internet and calling.

E-commerce has also been opened up as technology has progressed where we are moving to the

stage where everywhere you go to shop you will be paying electronically. Internet shopping has also

been created by E-commerce. There are various applications used for Internet shopping such as

EFTPOS (Electronic funds transfer at point of sales) and PayPal. Other utilities that are not for

internet shopping include credit cards and debit cards. These applications and utilities have made

shopping much easier as there is no need to carry out high amounts of cash when you can simply

keep it in a virtual account or a card. Transactions are also much faster because there is no need to

count cash and transferring money is also much easier as you can transfer billions of dollars in a few

seconds. Although this makes business much easier, it has also made people more wary of security

and how important it is. This is because these electronic appliances have created hackers who greed




from people who are uninformed and attempt to get their banking details. There are also

disadvantages to internet shopping such as vegetables and clothes not being in their physical form

for you to see. This can be a problem if you get a bag of tomatoes that have a few rotten or clothes

that do not fit you. Internet shopping has also opened up new ways for businesses to run. For

example, a game company can create virtual cash that you can buy via PayPal using real cash and a

more common phenomenon, companies selling their products online.

As you can see, communications has changed the way we communicate socially and the way we

conduct business in many different ways. It has become much easier to socialize as time has

progressed going from physical communication to fax, to telephones, to e-mails and so on. Multi-

touch devices that have been introduced are also quite popular with people of all ages because they

are easy to use and have many great utilities. Businesses are also are more relief because

communicating with each other during work could never be easier and when it couldn’t have been

better, more business options have been opened.

7. Encryption is often used when transferring data to keep it secure, explain how the

encryption process is carried out.

The internet has opened up many communication channels in a new era with a new world.

These communication channels let us communicate with people who we do not know all

and also open up transmission channels where we can send and receive data to anyone and

from anyone. Because people can easily tamper what happens before, during and after

transmission, security systems must be introduced. Hiding your information is definitely not

enough in this world and nor was passwords. This is why encryption was introduced, a new

way to protect data and information. Encryption is the physical version of coding all your

work and giving the code to the receiver so that he can decode it. It can benefit you in many

ways such as if confidential files are stolen during transmission, the information cannot be

decoded and will be completely useless. Only the receiver, who is able to decode the files is

able to make use of the encrypted file. There are typically two types of encryption:

Symmetric key encryption (private)

Asymmetric key encryption (public)




Symmetric key encryption, as stated above is a private way of encryption where only the

sender and receiver know the code and are able to decode it. It generally means that the

same key is used for encrypting and decrypting the data. The first symmetric key encryption

was DES (Data Encryption Standard) which featured a 56-bit key. This was eventually

scrapped as it is much too weak for modern day standards when the Electronic Frontier

Foundation publicly broke the key in 22 hours and 15 minutes. This was then succeeded by

AES (Advanced Encryption Standard) which is able to feature a 256-bit key. This is the

current encryption method used worldwide as of 2011.

Private key encryption

Unlike symmetric key encryption which uses the same key for both encrypting and

decrypting, asymmetric key encryption has 2 keys that are used for encryption and

decryption, a public key and a private key. A public key is published to everyone who has a

secure connection with the transmission of the file and a private key is only known by the

receiver.




Public key encryption

8. Outline the roles of a Network Administrator of a company for a computer

Network consisting of a file server, a proxy server, 120 workstations and 900

users, and is part of WAN of 100 similar companies.

Network administrators are extremely important within a network. They are the physical

equivalent of a government within a network. Without one, everything would be jumbled

up and all over the place. They are responsible for many things such as maintenance of the

hardware and software which would mean that they must have knowledge on how to install

and fix all types of hardware and software including routers, switches and hubs. Along with

this, they are also responsible for monitoring and providing help to users and clients by

controlling privileges and taking care of the network in general. Because they have to take

care of the network, it is compulsory to be able to keep up with technology.

A network administrator has the highest access rights in a network. They have complete

control of everything which means that the job of a network administrator is very tough.

They must be trustworthy enough to be able to gain these privileges and have a high

amount of work to do. One of the main tasks of a network administrator is to manage the

users. In this case, there are 900 users in this network. They must add and remove users

from the network and give different privileges to the users depending on the type of group

that they belong in. In every network there will be different classes of people with different

privileges such as in the Sydney Technical High School network, students, parents and




teachers are all assigned different privileges. People will be placed into different groups and

will be assigned these privileges by the operating system’s ACL (Access Control List). These

privileges will include such authorisations such as:

Read – Users are able to read the content of files and be able to see the directory

contents

Write – Users are able to change the content of files in 4 ways; adding, creating,

deleting or renaming.

Execute – Users are able to run programs and access them

Authentication details will then need to be assigned to the users where they will be able to

change their passwords at their will. These accounts have a personal profile that is saved

onto the server. There must also be other small things to consider for example, if a user is

removed from the network, their account must be terminated. Also, if a user’s account has

reached a certain time of inactivity their password will either need to be reset or their

account will be terminated.

The 120 workstations must also be managed by the network administrator. The network

administrator must be able to ensure that each of the 120 workstations are ready to use.This may sound like an easy task but in reality it is difficult. Each of the workstations must

have a specific operating system so that if there is a problem with one of them, the problem

can be recorded and fixed. Each of the workstations must also have a security system which

will most likely include a virus scanner and a firewall which is reliable. If the security is

unreliable, the workstations could be hacked and personal information can be taken from

the users. Internet must also be ensured to all of the workstations if necessary which means

connecting each of them to a router and setting up switches. The network administrator

must also license appropriate software for each of the workstations which is taking in a high

amount of responsibility as well as considering finance.

This brings the network administrators to be able to manage the WAN (Wide Area

Network). The network administrator must ensure that their network is connected to the

WAN of the other 100 networks and the internet. The only way to communicate with the

100 other networks is via the internet. The internet is also required for the users to be able




to use the workstations more efficiently and productively. To be able to do this, a suitable

router that is able to connect 120 workstations and is able to connect to 100 other routers

in the same WAN must be installed. This means that he must choose a suitable price and

capability of a router and connect to the 120 workstations. The network administrator must

also set up switches to enable the internet usually via Ethernet. As stated before, security is

an important issue for workstations. It is also an important issue for the router. The router

will need to be able to fend of malicious content and stop unwanted clients from accessing

the router. There are 3 protocols that can be used for this, WEP, WPA or WPA2 as stated in

question 2. The WPA2 will be used in the modern day world because it is more efficient with

encryption. Filters and censors should also be placed onto the router so that the users are

unable to access websites that are not suitable for work or contain malicious content

(Blocked sites in STHS).

The file server must also be managed by the network administrator. This means that he

must keep it safe and working at all times which means protecting it from malicious content,

preventing data collisions etc. The file server must have security on it at all times as it has

lots of confidential information which the users may need in the present or future. This also

means that the file server must be scanned regularly so ensure that nothing malicious hasentered. Data collisions must also be managed. Typically CSMA/CD (Carrier Sense Multiple

Access with Collision Detection) should be managed and checked regularly. A regular backup

with the file server should also be done in preparation of the worst.

Keeping up with technology is another thing that the network administrator must do. If

there is a virus outbreak then he must be there to ensure that the file server is not affected.

The 120 workstations should be upgraded every few years so that the system performance

does not drop drastically and that they are kept up to date. He must also ensure that the

operating systems of these workstations are being updated regularly by monitoring them.

9. The Client-server architecture is used on most networks. With the aid of two

examples explain why this type of architecture is so important.

Client-server architecture is exactly what it literally says. It is the relationship between a




client and a server. The server is usually a large network and the client is usually a personal

computer but not limited to this. A computer can easily act as a server although it is not as

reliable to a large network. The server provides processing resources and services to the

clients. For example, a web server retrieves and transmits web pages and clients receive it

(browsing the internet).

There are many types of types of servers, web servers, file servers, mail servers which each

carry out a specific role on the internet but there are only 2 types of clients; fat clients and

thin clients. Fat clients are clients that are able to process data, request information, run

applications etc. by themselves as thin clients rely heavily on the server to fulfil what a fat

client can do independently.

A client-server relationship is extremely common in the modern day and is the most used

type of network currently used. As said before, a computer can be either a client or a server.

On the internet, a personal computer will most likely be a client. The reason for this is

because a server needs to be extremely strong and expensive for it to be able to receive

information and transmit information simultaneously to many different clients. The

relationship on the internet between personal computers and servers (web servers and file

servers particularly) are where personal computers can upload onto a server. A server hosts

and stores the files and processes requests by other clients and transmits data to them. An

example of this is where a client wants to share data with other clients whom they are only

connected to via the internet. Because of a personal computer’s slow speeds, it is much

faster to upload the data to a server and let the recipient download it then send it directly. A

client would upload their data onto a file server and the recipient (other client) will then

visit the server using a URL (Universal Resource Locater) and download the file.

Client-server architecture is extremely important for speed and security. Although a server

costs much more than a personal computer, it has many more benefits as a central node of

transmission. A server has much more security of the files and will prevent unauthorised

access but a personal computer has a high risk of unauthorised access, lower speeds and

lack of security. If a client-server relationship did not exist, files would be transferred from a

fat-client to another fat-client which would result in extremely slow speeds. Backing up and

error checking is also much easier because all the files are stored in one place. If a personal




computer was to be the server, the files would be very messy and unorganised.

The relationship between a server to a client

10. Explain the operation of a packet switching network? Give an example where

packet switching is used.

A packet switching network is a network that is able to split data upon transmission into

more suitable sized blocks called “packets”. These packets are generally small and easy to

manage as they are around 1000 bytes. The purpose of packet switching is to make

transmission more efficient by allowing simultaneous and fast transmission as well as

reducing the amount of errors occurring. It was also made to utilize the channel capacity of

a network more efficiently to reduce the latency.

The software for packet switching first divides the data into a reasonable amount of blocks

and assigns an envelope which includes the destination and the instructions of how the file

will be put back together at the end of the transmission. The file then goes off to

transmission as the network places the little packets into different paths which all reach the

same destination. These paths are decided on depending on the channel capacity of each

path. At the end of the path, the envelope will be read by the routing software and put back

together into the large file that was intended to be received regardless of the order they

were sent in. This is an extremely useful technique because if an error had occurred, one

single packet would simply need to be resent but if you were downloading a large file and

an error had occurred, the whole file would have been needed to be resent which is an




extreme disadvantage especially if you have slow internet.

An example of where packet switching is used is when a student is attempting to download

a textbook from the Sydney Technical High School website. The student would first request

the HTML webpage and will be asked for authentication details. After authentication details

are entered, the student locates the resource where the textbook is found and attempt to

download it. The textbook will go through Sydney Technical High School’s routing software

and be divided into a reasonable amount of packets upon transmission. The routing

software will then place an envelope on each of the packets in order for the student’s

routing software to understand how to put it back together. The file will then be

transmitted to the student via the internet with a little help from the TCP (Transmission

Control Protocol) protocol acting as a delivery system. The packets will then go through an

error checking system of either parity, checksum or CRC (Cyclic Redundancy Check). If they

contain no errors the packets will then move on to the next step. If there are errors then

one of the packets will be resent. The routing software from the student will then put the

packets into one big file in advance to sending it to the student. The IP (Internet Protocol)

protocol then directs the file to the student.

Packet switching is an extremely useful technology that has changed the way files are

transmitted by making it faster and more efficient. It is the modern way that files are

transmitted and current provides satisfaction to users.

11. Evaluate the different forms of broadband Internet connection (ISDN, ADSL,




ADSL2 and Cable) for use in a small online business of eight employees.

A small business online of eight employees, as for any business online will require stable

broadband connection will instantly rules out dial-up. The internet must be able to upload

and download significant amounts of data but do not need to be too intensive to download

100s of gigabytes. The four different types of broadband connection which can be used for a

small online business are ISDN (Integrated Services Digital Network), ADSL (Asymmetric

Digital Subscriber Line), ADSL 2 (Asymmetric Digital Subscriber Line 2) and Cable. They are

all unique and have their ups and downs.

ISDN is one of the first types of broadband made. It was defined in 1988 and is now

currently out-dated. ISDN is a type of broadband that connects to the internet via PSTN and

sends digital transmission signals of various types of data over PSTN. It is a symmetrical type

of network which means that download speeds and upload speeds are very similar. This is

particularly useful for businesses that need to transmit data to their clients. When it was

created, the world was currently using analogue modems (dial-up) instead of digital

modems which were much slower. ISDN would be permanently connected to the network

while other analogue modems would need to dial up to connect to the internet. This made

ISDN the more efficient network by far. However, it was also must more expensive. At the

time, your everyday home would not have ISDN because it would be too much to afford and

the internet did not have many users or data at the time because of the unreliable speeds of

analogue modems. Along with speed and utility, ISDN would also offer extra features such

as being able to be on the phone and on the internet at the same time which analogue

modems could just not. As you can see, with all the efficiency of ISDN, the features would

have definitely been needed during the 1980s to the 2000s but in the modern day, there are

much better choices than ISDN.

ADSL is an asymmetric network which means that the upload speeds and download speeds

differ greatly. The download speeds of ADSL can go up to 256kb/s but the upload speeds of

ADSL can only go up to 64kb/s. As you can see, this is a huge difference which makes it

optimal for personal use but for businesses it is extremely situational. ADSL uses a copper

wire to transmit their data which is digital and do not convert them into analogue signals.




The hardware and software for ADSL is very vital. An ADSL modem and an ADSL filter would

be needed and there would be device drivers and routing software to make ADSL work. It is

also recommended to have software that will protect you (Firewall, virus scanner) from

malicious files.

ADSL’s speeds are the extremely fast compared to ISDN. This is probably one of the main

advantages that ADSL have over ISDN. ADSL also shares many of the features that ISDN

already have such as being able to use the phone and internet at the same time which is an

extremely vital part of a business. Imagine running a business and not being able to use the

phone and internet at the same time. It would be very on and off and will ultimately fail.

ADSL is also always on meaning that you will not have to dial up every time you want to use

the internet which could take a lot of time. As stated before, ADSL is situational for

businesses because of the difference in upload and download speeds. Another reason for

this is because of location. The business would need to be very close to an ADSL exchange to

maximize their potential especially if there are 8 employees all using the same internet.

ADSL also provides a high amount of utility to the users. The reason for this is because you

can simultaneously access the net as long as you are connected to the same copper

telephone line. It is also generally easy to set up and fix if there are any problems. This may

not sound like a big deal but having the internet fixed as soon as there are problems is

surprisingly vital. If a business must shut down for a week or two, it would affect the

businesses income and reputation greatly especially because they are only a small business,

people may forget about them and never visit them again. ADSL is recommended for

businesses that are close to ADSL exchanges and do not require a high amount of upload

speed, optimal for a small business because if there are 8 employees, there would most

likely be a low amount of items that are needed to be uploaded.

After ADSL, another type of broadband was introduced which succeeded ADSL with its extra

features and boosts, ADSL2. ADSL2 has all of ADSL’s features but more. There are many

different improvements such as a higher range of capability over long distances. This is a

huge disadvantage to DSL if they are not close to the ADSL exchange but luckily ADSL2 has

almost fixed this problem. Some of the other features that it provides are improvements in

data rate, dynamic data rate adaption, stronger resistance to noise, diagnostics (very useful




to users who are new) and a stand-by mode to save power. It has also reduced the start-up

time from ADSL’s 10 seconds to less than 3 seconds. It also adds support for new

applications and services.

Unlike the other types of broadband, Cable is a broadband internet connection which does

not use a copper telephone line but uses a coaxial cable. These cables deliver data to the

user the same way it delivers data to a TV. The peak speeds of cable are unrealistically fast

and go up to 50 megabits/s (not to be confused with megabytes) for downloading and 20

megabits/s for uploading. These speeds will definitely benefit a large business but for a

small business of 8 people, they will not need high speeds like this. However, cable

networks have extreme disadvantage. The more people that are using the network, the

slower the internet will be.

Cable network will most likely never be at its maximum performance during work hours

because it is a shared network and is shared with other users among the same network. This

will definitely happen during work hours or as they say, peak hours where people will all be

using the internet at once meaning that it will be a great disadvantage for the business.

Another big disadvantage for this network is the high installation cost which of the small

business of 8 people will most likely be unwilling to pay for the small amount of features

that they will be receiving.

In conclusion, I recommend ADSL2 for this small business for a number of reasons. First of

all, in terms of speed ADSL2 will satisfy their needs pretty well as well as giving them some

extra space. The extra speed from a Cable network which is ultimately unreliable is not

needed because they are only just beginning and they will not be transmitting or receiving a

high amount of data. Features are also another reason. ADSL2 contains all the features that

ISDN and ADSL has as well as more features such as power saving. The only vital features

that this business needs are pretty much being able to use the phone and internet at the

same time. The third and final reasons are because it is extremely cost efficient. It is cheap

to install and manage as well as easy and cheap to fix. Additionally, using the extra money to

buy a Cable network for nothing more that they need is irrelevant. ADSL2 is a reliable, fast

and efficient network for a small online business of 8 employees and will satisfy them.



Bibliography

Books

Samuel Davis, 2007, Information Process and Technology, Parramatta Education Centre Pty.

Ltd PO Box 26, Douglas Park NSW 2569

Websites

http://www.google.com/

http://www.google.com/imghp?hl=en&tab=wi

http://www.wikipedia.org/

http://www.howstuffworks.com/

http://www.wisegeek.com

http://www.webdevelopersnotes.com

http://www.tcpipguide.com

http://reviews.cnet.com

http://compnetworking.about.com

http://broadband.gov

bryan ye, year 9 ipt, mr simmonds, 2011 communications assessment task

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