3.1 The Internet

Question 1

What is the internet?

Answer 1

The internet is a collection of inter-connected networks

Question 2

What is the world wide web?

Answer 2

• One service that makes use of the internet. It is accessed from a browser and HTTP to send or receive data
• It is accessed from a web browser such as Chrome, Safari, Edge or Firefox
• It makes use of HTTP to send and receive data

Question 3

What is a wide area network?

Answer 3

• Using recourses supplied from a ‘third party carrier’ and have a number of geographical locations
• A WAN uses cables, telephone lines, satellites or radio waves to connect two or more remote locations
• The internet is the largest WAN in the world

Question 4

Give some examples of organisations which could have WANS

Answer 4

• Universities
• Schools
• Large companies
• Governments
• Research organisations

Question 5

What is the Internet of Things (IoT)?

Answer 5

Devices such as mobiles, parking metres etc. In 2020, over 31 billion IoT items connected to the interenet

Question 6

What is an IPv4 address?

Answer 6

An internet protocol which is represented by 4 8-bit numbers (0-255) separated by dots, for example 72.129.214.16

Question 7

What is an IPv6 address?

Answer 7

128-bit numbers represented in hex

Question 8

What is circuit switching?

Answer 8

A dedicated connection between 2 clients

Question 9

How does packet switching solve circuit switching in a large network?

Answer 9

It uses multiple connections and routers to send it to the right destination

Question 10

What is packet switching?

Answer 10

Each file is broken up into data ‘packets’ of 512 bytes, and each file is given headers

Question 11

What “meta data” is in each packet?

Answer 11

• The IP address it is going to
• The IP address it has come from
• The sequence number of the packet
• The number of packets in the whole communication
• Error checking data

Question 12

Why may packets go and take different routes?

Answer 12

A router may decide which path is better, faster and safer to go through

Question 13

How do packets come back in the same order and still have the same data?

Answer 13

• The client re-orders the packets into the correct order

- Corrupt packets are requested to be resent etc.

Question 14

Nodes

Answer 14

Points on a network digram

Question 15

What do routers do?

Answer 15

Routers are nodes that can routes packets from one place to another

Question 16

What is a Domain Name System (DNS)?

Answer 16

A domain name is a name used to refer to an IP address. A DNS server translates a web address (URL) into an IP address.

Question 17

What are DNS root servers?

Answer 17

13 database servers which contain a complete database of all domain names and IP addresses.

Question 18

What happens if a DNS server receives a request and data is not in its database?

Answer 18

It will pass the request on to another server until it reaches one with the matching name and IP address. ISP’s are owned by lower level DNS servers

Question 19

Why might your IP address change?

Answer 19

The IP address is the one that belongs to your router that you are connected to.

Question 20

What is dynamic IP address?

Answer 20

When a router retries to connect to the internet, it may receive a new IP address

Question 21

What is a Network Interface Card (NIC)?

Answer 21

A card that connects to a modem (router)

Question 22

What is MAC (Media Access Control) addressing?

Answer 22

A unique MAC address assigned to a device (2 ^ 48 possible mac adresses)

Question 23

What is the role of a MAC address?

Answer 23

A router uses a MAC address of the next router to send the data packet on the next leg of it’s journey

Question 24

WAN

Answer 24

Wide Area Network

Question 25

Packet

Answer 25

One unit of data sent through an IP address

Question 26

Routing

Answer 26

Directing IP packets to their destinations

Question 27

DNS

Answer 27

Domain Name System

Question 28

IP address

Answer 28

Internet Protocol Address. Where packets of data are sent to or received from

Question 29

MAC address

Answer 29

Media Access Control address. The unique identifier of each device