Communication

Question 1

Is it conventional telephone using pstn or internet based system
1)connection only in use whilst sound is being transmitted
2)dedicated channel used between two points for the duration of the call
3)connection maintained throughout the telephone call
4)encoding schemes and compression technology used
5)lines remain active even during power outage

Answer 1

1)interent based
2)con
3)con
4)i
5)con

Question 2

Distinguish between the internet and the world wide web

Answer 2

Internet
-interconnected network of computer devices
Internst stands for interconnected network
- it uses tcp/ip protocol

World wide web (www)
-is a collection of web pages / documents
-stored on websites
-it uses http/protocols and are used to transmit data
-web pages are written in html
-web documents are accessed using the browser

Question 3

A device that transfers data from one network to another in an intelligent way tash of forwarding data packets to their destination by the most efficient route

Answer 3

Router

Question 4

A device used between two dissimilar Lans. The device is required to convert data packets from one protocol to another

Answer 4

Gateway

Question 5

A device or software that provides a specific function for computers using a network. The most common examples handle printing. File storage and the delivery of web pages

Answer 5

Server

Question 6

Describe what is meant by a client server model of networked computers

Answer 6

-At least one computer is used to serve
-other computers are reffered to as “clients”.
- server provides services or applications etc
-which may be requested by the clients

Question 7

Give two benefits of client server model

Answer 7

Files and resources are centralized
Creation of security
USER needs a username and password to access the network
Centralized back up
Internet monitoring

Question 8

How a web page offers a link for users to request another web page. The requesting contains html code and have script code

Answer 8

1)the user clicks on the hyperlink and the web page is requested from the web server
2) the web server locates the request web page
3)the requested web page content is transmitted to the client computer
4) the client computer processes the have script code using the web browse software
5)the requested web page is displayed on the client computer

Question 9

Explain the difference between the world wife web and the internet

Answer 9

www is a collection of interlinked, hypertext documents/web pages/multimedia resources (accessed via the internet)
Internet is the global connection of interconnected computer networks
The internet uses tcp /ip protocol

Question 10

What type of cable is
1) wireless medium
2)twisted pair is an example
3)uses light waves
4)wifi
5)fastest transmission medium

Answer 10

1)radio waves
2)copper cables
3)fiber optic
4)radio
5)fiber optic

Question 11

Describe one difference between real time and on demand but steaming.

Answer 11

Real time - a live stream of an event that is currently taking place
On-demand-streaming of an event/programme that had taken place in the past

Real time-the event is captured love with a video camera connected to a computer
On demand - existing media are encoded to bit streaming format and uploaded to a server

Real - cannot be paused rewound
On demand - cannot be paused or rewinded

Question 12

Describe, using an example, the format of an ipv4

Answer 12

Four numbers separated with ‘.’
Each number is between 0 and 255
32 bits long

Question 13

Describe how the browser uses the domain name server(dns) to display the web

Answer 13

Url is a reference address to a resource on the internet
The Url is passed to the near domain name server (by browser software)
Dns server stores a data base which has list of Url and matching ip addreses
Dns (name resolver) like for the url in its database
Finds the matching ip address and returns it to the originator
Or if they can find it they forward it to another domain server at a higher level

Question 14

Describe how it is possible to watch the video without it continually pausing

Answer 14

User needs high-speed broadband(connection)
Data is streamed to a buffer(in the computer)
Buffering stops video pausing as bits streamed
AS buffer is emptied it filles up again so that viewing is continuous
Actual playback is (a few seconds) behind the time the data is received by computer

Question 15

Downloading a file from a website is an example of a client server application
Describe what is meant by the term client server for this application

Answer 15

The file is made available from a web
The users browser is the client software
The client (software browser) requests the file from the server
The desired file Is returned to the client computer

Question 16

State how a computer could access the web page without using a domain name (Dns)

Answer 16

Use the ip address instead of the url

Question 17

Public or private
1) 192.168.2.1 is an example of this type of address
2)assigned by the internet service provider (isp)
3)ip address cannot be duplicated in different networks
4)network address translation (nat) is necessary to access the internet directly

Answer 17

1)priavte
2)public
3)publjc
4)private

Question 18

Give two types of transmission medium

Answer 18

Copper cable
Fiber optic
Radio waves
Microwaves
Infrared

Question 19

Describe the purpose of an ip address

Answer 19

-gives each device on a network an identifier
Each address is unique within the network
Allows a device, gateway, or node to send data to the correct destination

Question 20

Benefits of Fibre optic cable over copper cable

Answer 20

Less interference in signal
Signal does not degrade as fast
More difficult to hack
Greater bandwidth

Question 21

Drawbacks of Fibre optic cable over copper cable

Answer 21

Intial installation cost is higher
Specialists or a trained personnel needed to install
Difficult to terminate, electronics at both ends are more complex
Fibre optic cables can break when bent
Only transmit Data in one direction
If a Fibre optic cable connection fails, many more services can be affected

Question 22

Describe how a url is converted into its matching ip address

Answer 22

Url is parsed to obtain the domain name.
Domain name is sent to the nearest domain name server (dns)
Dns holds a list of domain names and matching ip address
Dns name resolver searches it’s databases for the domain server
If Dns does not find the domain name the request s forwarded to a higher level.
If the domain name is found. The ip address is returned
ID the domain is finally not found.

Question 23

Why this file needs to be compressed

Answer 23

Data files are very large
It would take a long time to send the uncompressed file
A higher bandwidth would be needed to transmit the uncompressed file

Question 24

Define the term lossy compression

Answer 24

Data is lost
The decompressed file is not the same as the original

Question 25

Explain why lossy compression is lore appropriate compression technique than lossless for this file

Answer 25

Lossy creates a smaller file than lossless
The recording of the concert is large file size and needs significant reduction in size
Lossy removes detail which can be lost without people noticing
By example eg. Reduction in sound quality will not be noticed

Question 26

Describe the transmission of data using pstn

Answer 26

Tye pstn consists of many different types of communication lines
Data is transmitted in both directions at the same time
The communication passes through different switching centers

Question 27

Explain why the web application uses server side scripting

Answer 27

All data is held on the server
The server only sends the results of the query to the client
The client does not have access to all the data
Which keeps the data more secure
Customers can be identified when they log in from a database of user names and password