2.3 Internet Principles of Operation

Question 1

Cookies

Answer 1

A small data packet sent from a website and…

• …STORED in a user’s WEB BROWSER while the user is browsing that website.
• Every time the user loads the website, the browser sends the cookie back to the server to notify the website of the user’s previous activity.
• can store passwords, credit card details, address so that they no need to be re-entered in the future
• to track what the user has viewed on the website, so that the owner of the website can send them adverts that match their preferences

Question 2

TCP/IP

Answer 2

• TCP (Transmission Control Protocol) controls how data packets are transmitted along Internet connections
• IP (Internet Protocol) makes sure data packets are sent to the right IP address

Question 3

Internet Protocol (IP) address

Answer 3

• A unique address used to identify each device connected to the internet
• 32-bit number (4 bytes)
• allocated by the network/ISP
• can be used in place of URL
• can be IPv4 or IPv6
• can be static, meaning it doesn’t change each time a device is connected to the Internet
• can be dynamic, meaning it can change each time a device is connected to the Internet

Question 4

Media Access Control (MAC) address

Answer 4

A unique number that identifies a device connected to the Internet
- 48-bit number (6 bytes)

Question 5

Difference between IP address and MAC address

Answer 5

A device’s IP address is used to route data across the Internet to its LAN, then its MAC address is used to switch data across the LAN to the device itself

Question 6

Computer network

Answer 6

A group of computers linked together to allow them to share resources (hardware, software, data etc.)

Question 7

The Internet

Answer 7

A network of networks that covers the whole world

Question 8

10 roles of an Internet Service Provider (ISP)

Answer 8

• Provide access to the internet
• Usually charge a monthly fee
• Monitor usage
• Give users an IP address
• Determine bandwidth
• Supports domain names
• Provide security services
• Provide web hosting facilities
• Provide access to Email
• Provides online data storage

Question 9

4 things a computer must have to be connected to the Internet

Answer 9

1. An ISP
2. A modem or router (wired/wireless)
3. Internet software, ie. web browser or app
4. Shared protocols, eg. TCP/IP

Question 10

Web page

Answer 10

A multimedia document that you can read over the Internet; it is created in a format called HTML

Question 11

Website

Answer 11

A collection of web pages, stored on a web server

Question 12

Web server

Answer 12

A web server hosts web page (holds the content of the web page in its storage). It will send the contents of the web page along an Internet connection to another computer.

Question 13

Web browser

Answer 13

1. Software that allows a user to display a web page on their computer screen
2. Interprets/translates the HTML document
3. Provides functions, such as bookmarks and history

Question 14

How does a web browser work?

Answer 14

1. Gets the web server’s name from the URL to connect to the web server
2. Web server transfers a copy of the web page onto your computer
3. Inteprets the HTML code and displays the web page so that you can interact with the content

Question 15

Hyperlink

Answer 15

A piece of text or image (eg. button) that opens a new page in your browser when you click on it

Question 16

HTTP

Answer 16

Hypertext Transfer Protocol is the protocol that makes hyperlinks work

Question 17

HTTPS

Answer 17

HTTP secure. It has extra features, compared to HTTP:

1. Authentication (checking that websites are not fake)
2. Encryption (so nobody can see what you send to a website)

Question 18

Protocol

Answer 18

A protocol is a shared standard/set of rules for communication

Question 19

Domain Name System (DNS)

Answer 19

A directory of all the domain names in the world; the DNS matches domain names to their IP addresses

Question 20

Hypertext Markup Language (HTML)

Answer 20

• a mark-up language used to create web pages
• translated by a web browser to display web pages
• uses (opening and closing) tags to format content

Question 21

What is a markup language?

Answer 21

A markup language is used to add descriptions (tags) to pieces of text in a document

Question 22

How does the web browser use the URL to access the web page?

Answer 22

1. The web browser sends URL to DNS
2. DNS stores an index of URL and matching IP address
3. DNS searches for URL to obtain the IP address
4. IP address sent to web browser, (if found)
5. Web browser sends request to IP of web server
6. Web server sends web page to web browser
7. Web browser interprets HTML to display web page
8. If URL not found DNS returns error

Question 23

HTML structure + example

Answer 23

Instructs how the LAYOUT of the content of the web page is displayed
Example: placing an image alongside some text

Question 24

HTML presentation + example

Answer 24

Instructs how the content of the web page will be FORMATTED, eg. colour (applied to some text)/style/CSS

Question 25

Describe the use of structure and presentation in a HTML document.

Answer 25

• Presentation is used to format colour/style
• Structure is used to create layout
• In a HTML document structure and presentation are often kept separate
• By keeping the presentation separate it is easier to update colour/font
• Presentation is often stored in a file called a CSS …
• … the CSS in then linked to the HTML document to implement the presentation requirements
• (Mark-up) tags are used to define the structure of the document …
• … presentation and formatting can also be included within the tags

Question 26

State what is meant by a URL.

Answer 26

• Uniform Resource Locator
• the website’s address
• user friendly version of the IP address