Unit 3 - Networks and Protocols

Question 1

What is the internet?

Answer 1

A worldwide collection of interconnected computer networks.

Question 2

What is a WAN?

Answer 2

A Wide Area Network covers a large geographical area that connects LANs.
Infrastructure between the LANs is hired from telecommunication companies who own and manage it.

Question 3

What is the biggest example of a WAN?

Answer 3

The Internet

Question 4

What is a LAN?

Answer 4

A Local Area Network covers a small geographical area on a single site.
All the hardware for the LAN is owned by the organisation using it.

Question 5

What are LANs wired with?

Answer 5

LANs are wired with transmission medias such as:
. UTP ( Unprotected Twisted Pair) cable
. Fibre Optic cables.
. Wireless using routers and Wi-Fi access points.

Question 6

How are WANs connected?

Answer 6

WANs are connected with transmission medias such as:
. Telephone lines
. Fibre Optic cables
. Satellite links

Question 7

What is an IP adress?

Answer 7

An Internet Protocol address is a unique string of numbers separated by full stops and is used to identify each computer using IP to communicate via a network.
It also also used to identify where data packets need to be sent and where they have come from.

Question 8

What are the 2 different versions of IP addressing?

Answer 8

IPv4 (4.3 billion addresses only) and IPv6 (a lot)

Question 9

What is a circuit switching network?

Answer 9

. Circuit switching lets you send digital messages across a network by setting up a physical path between the sender and receiver.
. This is done using wires or fibre optic cable and is set up prior to transmission of the message.

Question 10

What is packet switching?

Answer 10

Packet switching is breaking data into packets (Each data packet would contain the same number of bytes.), sending them across the Internet to another computer, and then reassembling the data and error-checking it.

Question 11

What happens if there are any lost or corrupt packets?

Answer 11

The recipient’s computer would acknowledge what had happened and packets would automatically be resent after a set time interval.

Question 12

What is a router?

Answer 12

A router sends data between networks along the path that is least busy at that moment. It is required to connect a LAN to a WAN.

Question 13

What is a DNS?

Answer 13

A Domain Name System or server takes a domain name from the user such as ‘www.bbc.co.uk’ and translates it to an IP address and then directs it into the requested website

Question 14

What is a URL?

Answer 14

. A Uniform Resource locator is used to specify the means of accessing a resource across a network and its location.
. The protocol and the domain name of the resource together form the URL.

Question 15

Why do IP Addresses sometimes change?

Answer 15

An IP address can be static or dynamic
. When a device is assigned a static IP address, the address does not change every time it connects to a network.
. Most devices use dynamic IP addresses, which are assigned by the network when they connect and change over time.

Question 16

What is a NIC?

Answer 16

A Network interface card is hardware that connects a computer to a
network.
It can be wired or wireless

Question 17

What is a MAC address?

Answer 17

. A MAC (Media Access Control) address is a unique identifier given to devices which communicate over a local area network (LAN)
. MAC addresses are static, they can never change
. It is assigned to an NIC
. Made up of hexadecimal.

Question 18

How many bytes are there in a MAC address?

Answer 18

6 Bytes (48 bits)

Question 19

What is a router?

Answer 19

A router sends data between networks. It is needed to connect a local area network to a wide area network.
It uses the IP address on a device to route traffic to other routers.
Sends data packets on their way in the best direction.

Question 20

What is a switch?

Answer 20

A switch sends data between computers on a local area network. It uses the MAC address in the NIC on a device to route traffic.
Reduces network traffic and increases speed.

Question 21

What is a hub?

Answer 21

A hub is a small device that allows wired devices to connect to a network.

Question 22

What are the 4 types of network connection devices?

Answer 22

. Hub
. Switches
. Wireless Access Point
. Routers

Question 23

What are the advantages of networking?

Answer 23

. Sharing resources such as printers save money
. You can access your files from any computer in the network.
. Data is easy to back up as it is stored centrally on the server.

Question 24

What are the disadvantages of networking?

Answer 24

. Purchasing the network hardware is expensive.
. Managing a large network is difficult.
. Viruses may be able to infiltrate the network and infect every computer.

Question 25

What are the two different ways a LAN can be set up?

Answer 25

. Star
. Mesh

Question 26

What are the advantages of a star network?

Answer 26

. Fast data transfer as there are fewer data collisions.
. If one cable fails, the other workstations are not affected.

Question 27

What are the disadvantages of a star network?

Answer 27

. Requires additional hardware such as the central switch
. If the central device fails, the whole network goes down.

Question 28

What are the advantages of a mesh network?

Answer 28

. No single point of failure, it is a self healing network
. Expansion and modification can be done without disrupting the network.
. Data can be transmitted from different devices simultaneously

Question 29

What are the disadvantages of a mesh network?

Answer 29

. Can involve unnecessary connections
. Expensive to install cabling if doing wired connections
. Network maintenance and administration is difficult.

Question 30

What is an ethernet?

Answer 30

. A standard for networking local area networks using protocols
. Frames are used to transmit data.
. Uses twisted pair and fibre optic cables.
. A switch is used to connect computers.

Question 31

What is a virtual network?

Answer 31

A virtual network is a network that can securely connect geographically unrelated computers via the internet.
. Requires no direct physical connection but allows file sharing and communication.

Question 32

How is wireless transmission used?

Answer 32

Commonly uses radio waves to communicate
Susceptible to interference from objects and other nearby electronic or radio devices.

Question 33

What is a WAP?

Answer 33

A Wireless Access Point is hardware that allows a Wi-Fi-enabled device to connect to a network.

Question 34

What are the risks of wireless networking?

Answer 34

Criminal activity - Could bypass the firewall and plant viruses
Bandwidth stealing - Using the network to download anything. It causes the network to be slow.
Confidentiality - If not encrypted, an intruder can gain access to confidential information.

Question 35

What is Bluetooth?

Answer 35

A method of exchanging data wirelessly over short distances – much shorter than Wi-Fi. Examples of typical Bluetooth use could be, headphones, car mobiles etc.

Question 36

What is encryption?

Answer 36

Encoding readable data (plain text) into unreadable data (ciphertext). Only the intended recipient can decode the data using a special key. Protects sensitive communications against hacking.

Question 37

What is the key in encryption?

Answer 37

A sequence of numbers used to encrypt or decrypt, often data using a mathematical formula.

Question 38

What is private key (symmetric encryption)?

Answer 38

A single key used to encrypt and decrypt the message. It must be given to the recipient to decrypt it. The Caesar shift was the earliest form of this.

Question 39

What is public key (asymmetric encryption)?

Answer 39

Two keys are used. One to encrypt and one to decrypt. This one is much more secure as it means you dont have to send or reveal your key.