SLR 11 - Networks

Question 1

What is a network?

Answer 1

A group of connected devices

Question 2

What are the advantages of networks?

Answer 2

Users can share files
Users can share peripherals and connections to other networks
Users can share and access files from any computer in the network
Servers can control security, software and backups

Question 3

What are the disadvantages of networks?

Answer 3

Increased security risks
Malware spreads easily
If a server fails, networks may fail
Computers may run slowly if a lot a data is being processed in the network

Question 4

What are standards?

Answer 4

A set of specifications that allow manufacturers to make compatible products
An example is the use of protocols

Question 5

What protocols are used to communicate over a network?

Answer 5

TCP - Transmission Control Protocol
IP - Internet Protocol
UDP - User datagram Protocol

Question 6

What protocols are involved in webpage requests?

Answer 6

HTTP - Hypertext Transfer Protocol
HTTPS - Hyptertext Transfer Protocol Secure

Question 7

What protocol is involved in file transfers?

Answer 7

FTP - File Transfer Protocol

Question 8

What protocols are involved in Email requests?

Answer 8

POP - Post Office Protocol
IMAP - Internet Message Access Protocol
SMTP - Simple Mail Transfer Protocol

Question 9

What are routers?

Answer 9

Connect to Internet Service Providers
ISPs connect to the DNS and other routers

Question 10

What do modern routers connect too?

Answer 10

Devices on the LAN
Other routers on a WAN
Servers

Question 11

What is layering?

Answer 11

The decomposition of networking
Hardware / Software in each layer has a set responsibility providing services to later layers

Question 12

What are the advantages of layering?

Answer 12

Decomposition
Devices can be manufactured to operate at particular layers

Question 13

What is the most important protocol stack?

Answer 13

TCP / IP

Question 14

What are the layers of TCP / IP?

Answer 14

Application
Transport
Internet
Link

Question 15

What happens in the Application layer?

Answer 15

Network applications request data or webpages

Question 16

What protocols are in the Application layer?

Answer 16

FTP / HTTP / HTTPS / SMTP / IMAP

Question 17

What happens in the Transport layer?

Answer 17

Between 2 hosts settings are agreed and applied

Question 18

What protocols in the Transport layer?

Answer 18

TCP / UDP

Question 19

What happens in the internet layer?

Answer 19

The router address and packages data for transmission, it routes packets across a network

Question 20

What protocols are in the internet layer?

Answer 20

IP

Question 21

What happens in the Link layer?

Answer 21

Network hardware sets standards and facilitates binary transmission

Question 22

What are mediums can be used for link transmission?

Answer 22

Copper Wire, Fibre, WiFi

Question 23

What is TCP responsible for?

Answer 23

Establishing and maintaining end - end connections

Question 24

What does TCP add to split packets?

Answer 24

Its number in the sequence
The total number of packets
The port number

Question 25

What does IP add to packets?

Answer 25

The Source IP and destination IP

Question 26

What is a socket?

Answer 26

The IP address + the Port Number

Question 27

What does the port number contain?

Answer 27

The device the packet is being sent too (IP address) The application that requested the packet (Port)

Question 28

What does the link layer add to a packet?

Answer 28

The source and destination MAC address These are changed every hop in a WAN

Question 29

Why are both MAC and IP addresses needed?

Answer 29

In a LAN only the link layer is executed which creates a frame using the MAC address In a WAN the IP addresses create a packet

Question 30

How does the DNS work?

Answer 30

Users request a URL This is sent to the DNS The DNS maps the URL to an IP and returns it to a browser A GET request is sent to the web browser The page is then returned to the client

Question 31

What is Circuit Switching?

Answer 31

The creation of a temporary, dedicated link between the source and destination It guarantees transmission quality It can waste a lot of bandwidth as only 1 user can use the route

Question 32

What is the main problem with circuit switching?

Answer 32

It has a massive security problem due to the fact that if the wire is tapped all packets can be gained

Question 33

What is Packet Switching?

Answer 33

It breaks down data into smaller blocks each sent independantly It maximises bandwidth but lacks quality It is more affordable and efficient than circuit switching

Question 34

What are the problems with Packet Switching?

Answer 34

Packets may arrive out of order Packets may be lost in transmission and need to be requested again

Question 35

What does the server do in a client-server model?

Answer 35

It manages access and security It manages internet access Manages peripheral devices It provides email services It runs regular backups of data

Question 36

What does the client do in a client-server model?

Answer 36

It makes requests to the server for data

Question 37

What are the advantages of a client-server model?

Answer 37

It's easier to manage security It's easier to backup data It's easier to update devices

Question 38

What are the disadvantages of a client-server model?

Answer 38

It's expensive to setup and maintain It requires specialists for maintenance The server serves as a single point of failure Users lose access to a network on sever fail

Question 39

What are client-server networks best suited for?

Answer 39

Organisations with large numbers of devices where many devices need access to the same set of data

Question 40

What are the features of a peer-peer model?

Answer 40

A peer is equal to all other peers Peers are responsible for their own security and data Peers have their own devices Devices must be active for communication to occur

Question 41

What are the advantages of a peer-peer model?

Answer 41

Easy to maintain Cheap No dependancy on 1 connection

Question 42

What are the disadvantages of a peer-peer model?

Answer 42

It is less secure Users are responsible for themselves

Question 43

What are Peer-Peer models best suited for?

Answer 43

Smaller organisations with few devices and users accessing data