1.3.3 Networks

Question 1

lan

Answer 1

• group of computers/devices connected over a small geographical area
• use of wireless communication
• more secure
• easier to communicate/share data/maintenance

Question 2

wan

Answer 2

• covers a large geographical area
• uses third party connections
• less secure

Question 3

protocol

Answer 3

• set of rules
• to govern data transmission (between devices)
• by focusing on how data is represented
• e.g. character set

Question 4

domain name system

Answer 4

• used to resolve IP corresponding to URL
• request sent to DNS resolver
• resolver checks cache => if it doesn’t hold the URL => passes it into the TLD name server => checks cache/returns answer or passes to Authoritative Name Server
• IP address is returned back up to the requesting client.
• or an error if no resolution can be found

Question 5

layers

Answer 5

• allows different layers to be worked on independently
• allows layers to be replaced/upgraded without affecting others
• allows for layers from different providers to be used interchangeably

Question 6

packet switching

Answer 6

• data is split into chunks called packets and labeled => address being sent to and order
• each packet is sent on the most convenient / avoidable route => arrive in a different order to which they were sent
• once packets arrive at receiver they are reordered

Question 7

circuit switching

Answer 7

• direct link is created between two devices => dedicated channel
• data arrives in a logical order which results in a quicker reconstruction of the data

Question 8

firewall

Answer 8

• a hardware device/piece of software that monitors and filters traffic going to and from a network

Question 9

proxy server

Answer 9

• acts as an intermediary => collects/sends data on behalf of the user
• privacy of the user is protected => remain anonymous
• can cache frequently used website data => faster to load
• reduces web traffic

Question 10

peer to peer server

Answer 10

• no central server
• devices on the network share data
• easy to maintain/cheaper
• poorer security
• difficult to locate resources/origin of files

Question 11

client server

Answer 11

• client computers connect to server
• shared resources
• centralised security/back up
• expensive to set up
• if central server fails, performance fails

Question 12

application layer

Answer 12

• protocol decided eg. HTTPS for browser
• adds encryption/decrypts
• Passes onto transport layer when sending, gets data from transport layer when recieving

Question 13

transport layer

Answer 13

• end-to-end connection between source/destination
• data split into packets/labelled w/ packet number

Question 14

internet layer

Answer 14

• adds source/destination IP address

Question 15

link layer

Answer 15

• recieves from internet layer when sending, passes to internet layer when recieving across wireless network
• mac addresses added