Topic 9.2 Networking

Question 1

Explain what is meant by a physical topology

Answer 1

Describes how network devices are physically connected.
Via cables, wires, wireless

Question 2

Explain what is meant by a logical topology

Answer 2

The way the information and data flows around the network

Question 3

Explain a physical star topology

Answer 3

Each device (printer, computer) has its own connection to the central hub.

Question 4

Advantages of a physical star topology

Answer 4

• Easy to add new devices
• Nobody else can see your data being sent
• No possibility of collisions
• One cable failing doesnt affect the rest of the
  network

Question 5

Disadvantages of a physical star topology

Answer 5

• If central hub fails, everything fails
• Very expensive as lots of cable required

Question 6

Explain a physical bus topology

Answer 6

Every device is connected to a main cable which connects to the central hub.

Question 7

Advantages of a physical bus topology

Answer 7

Very cheap as only one cable needs to be installed

Question 8

Disadvantages of a physical bus topology

Answer 8

No confidentiality
- Every device on a network can see all your data being sent

Collisions
- Data being sent at the same time from 2 different devices means both devices will have to send their data again

Risky
- Central wire fails, everything fails

Question 9

Explain a logical bus topology

Answer 9

Devices behave as though they share a single wire connecting them all to the central hub.
Data sent by one device is heard by all devices in the network, but only read by intended recipient.

Question 10

Explain how a physical star topology can act as a logic bus topology.

Answer 10

If we use a hub instead of a switch in a PST, the hub does not make smart decisions about where to send data like a switch would, so it broadcasts data to all devices, exactly the same a bus topology would.
This also means that if data is sent at the same time, there will be a data collision and the data will have to be resent.

Question 11

Explain what is meant by peer-to-peer networking

Answer 11

Every device has equal status.
All devices able to share resources with each other without the need for a server
Everyone can request each other’s data.

Question 12

Advantages of peer-to-peer networking

Answer 12

No central points of failure
Cheaper due to no server
Scalable network so can grow easily

Question 13

Disadvantages of peer-to-peer networking

Answer 13

No central authority so very low security
Each device has to act as it its own server which uses a lot of computer resources (memory & processing)
Performance lowers due to reliance on devices with low-speed connections

Question 14

Explain where peer-to-peer networking may be used

Answer 14

Cryptocurrencies - no central security
Skype - used to use it for connecting users on voice and video calls
Minecraft - reduces latency between multiple computers

Question 15

Explain client-server networking

Answer 15

One (or more) server(s) provide services to multiple devices on a network.

Servers are connected to the network in the same way that devices are but are most likely a lot more powerful.

Services could be management of print queues and emails.

Question 16

Advantages of client-server networks

Answer 16

Control - all data is managed by a central server
Data backup - no risk of losing important data
High performance and high scalability
Very reliable

Question 17

Disadvantages of client-server networks

Answer 17

Very expensive - servers, security, maintenance
If server fails, everything fails
Security vulnerabilities

Question 18

examples where client-server networks may be used

Answer 18

all websites
all emails
all banks
streaming platforms
games
basically everywhere in all aspects of life

Question 19

Define wireless networking

Answer 19

Devices to communicate in a network without being a physical connection to the network (no cables & wires).

Question 20

Explain WiFi and its purpose

Answer 20

A method for devices to connect to the internet without the need for wires.
It creates a wireless network in a specific area (home or office) so devices can access the internet.
Wifi follows international standards (rules) to ensure all devices, no matter the brand, can connect and work together.
So any phone can access any wifi router since they all follow the same standards.

Question 21

Explain how wireless networking works

Answer 21

• Wireless router in your home or office
• Connects to the internet via a cable from
  your ISP (internet service provider) (sky, EE)
• Wireless access point (WAP) allows wireless
  devices to connect to a wired network
• Boosts the signal to extend the range
  devices can connect to it from
• Modem connects to the ISP to provide
  access to the internet and connects to the
  router
• Router broadcasts internet signals to your
  devices
• Router also acts as a WAP in most cases
• Wireless network interface card or Wireless
  network adapter are built into most devices
  and allow the device to connect to the router, which connects it to the wi-fi

Question 22

How does a Wireless Network Adapter or Wireless Network Interface Card work

Answer 22

They are built into most modern devices and allow the device to connect and communicate with the router, thus allowing the device to connect to wifi.

Question 23

How does a Wireless Access Point work

Answer 23

Allows wireless devices to connect to the wired network by boosting the range in which devices can connect to the router.
Most modern-day routers have a built-in function of WAP.

Question 24

How does Wifi Protected Access (WPA/WPA2) work

Answer 24

WPA encrypts the transmitted data.
requires that a new wireless client must enter the password before connecting to the WiFi.

Question 25

How does disabling SSID broadcasting work

Answer 25

SSID is the name that identifies a wireless network.
By disabling this broadcast, it stops wireless devices within the range of the network from displaying that the network is available
Only allows those who know the SSID to connect.

Question 26

How does MAC Address Whitelisting work

Answer 26

MAC addresses are uniquely assigned to every wireless device by their manufacturer.
By whitelisting specific MAC addresses, only specific devices will be able to connect to a network.

Question 27

What is the purpose of the SSID

Answer 27

To identify a WiFi network to allow devices to connect to it

Question 28

What is the purpose of the wireless protocol Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)

Answer 28

To avoid data collisions caused by multiple devices sending data simultaneously

Question 29

How does the wireless protocol CSMA/CA work

Answer 29

When a device is ready to transmit it checks the communication channel to see if there is already data being transmitted.
If data is already being transmitted, the device will wait a random amount of time and check it again.
When channel is empty, then data will be sent from device

Question 30

How does the additional functionality of Request To Send and Clear To Send work alongside CSMA/CA

Answer 30

Since there may be parts of the communication channel the device cannot see, it can result in data collisions still.

SO RTS/CTS waits until the device THINKS the channel is free, then will send a RTS signal.

IF not CTS then it will go back to waiting until the device thinks the channel is free and repeat until CTS signal is received.
Then the device can send the data.