1.3.1 - Networks and topologies

Question 1

What is a Local Area Network (LAN)?

Answer 1

A network in a small geographical area (same building or a small site)

Question 2

Who owns the infrastructure for a LAN?

Answer 2

Network owner

The organisation using it

Question 3

What is a Wide Area Network (WAN)?

Answer 3

A network in a large geographical area (across a country or multiple e.g. The Internet)

Question 4

Who owns the infrastructure for a WAN?

Answer 4

Third parties

Question 5

What affects network performance?

Answer 5

• Bandwidth
  -Interference (e.g. thick walls)
  -Transmission media
  -Amount of data being transmitted
  -Error rate
  -Latency

Question 6

What is bandwidth?

Answer 6

The maximum amount of data that can be sent across a network at once. Measured in bits per seconds

Question 7

What is latency?

Answer 7

The delay from transmitting media to receiving it. Caused by bottlenecks (a junction where data gets held up) in the infrastructure of the network.

Question 8

Explain why the number of devices using a network at the same time can affect the performance of the network

Answer 8

-Less data can be transmitted at the same time.
-More devices means more data being transmitted at a time.

Question 9

Explain why bandwidth can affect the performance of the network

Answer 9

-Bandwidth will be split between all devices
-therefore, there is less bandwidth for each device

Question 10

Explain why latency can affect the performance of the network

Answer 10

Increased latency means that devices have to wait longer before they can transmit data

Question 11

What are the advantages of using a Client-Server network?

Answer 11

• Controlled centrally: easy to backup data and update software
  -Makes access to files more secure as sensitive data is stored on the server rather than on individual clients
• Hardware, software and resources can be shared across the network
• Easy to add new clients to the network

Question 12

What are the disadvantages of using a Client-Server network?

Answer 12

• Traffic congestion will cause network to slow down
• Reliant on server: If the server fails, the whole network fails and users will lose access
• IT technicians required to maintain the network
• Malware can spread from the server to all computers on the network

Question 13

What are the advantages of using a Peer-to-Peer network?

Answer 13

• Simple setup: no server is required
  -Cheaper: No specialist staff or expensive hardware required
• Not dependent on a server
• Easy to share files between systems

Question 14

What are the disadvantages of using a Peer-to-Peer network?

Answer 14

• No central device to manage security or backups
  -Less secure as security software is individually managed
• More devices = decrease in performance

Question 15

What kinds of network hardware are there?

Answer 15

• Wireless Access Point (WAP)
• Router
• Network Interface Card (NIC)
• Transmission medium
• Switch

Question 16

What is a Wireless Access Point (WAP)?

Answer 16

Allows wireless enabled devices to connect to a network without cables

Question 17

What does a router do?

Answer 17

Transfers data packets between networks.
Required to connect to a WAN. Uses IP addresses to route traffic.

Question 18

What does a switch do?

Answer 18

Connects devices together on a network, allowing them to communicate.

-Sends data between computers on a LAN
-They segment the network by forwarding traffic to the correct location
-Switches learn which devices are connected and understand how to forward traffic in an intelligent way

Question 19

What does a Network Interface Card (NIC) do? What does it contain?

Answer 19

They use a protocol to determine how the connection should work. They allow a device to connect to either a wired or wireless network.

They contain a unique hardware address, called a MAC address

Question 20

Define the Internet

Answer 20

A worldwide network of computer networks

Question 21

Describe how a computer tries to find the IP address for a given domain name

Answer 21

-A website is hosted on a web server
-The website has an IP address
-The user enters a URL (Uniform Resource Locator) into a web browser
-The web browser sends a request for the matching IP address to the URL to the DNS (Domain Name Server)
-If found, the IP address is returned
-If the DNS cannot find the IP it passes the request to a higher DNS
-If the IP address is not found return an error
-The IP address is sent back to the computer/browser
-The browser then sends a request to the IP address for the website
-The webserver processes the request for the website
-The web server sends the webpage to the user

Question 22

Define hosting

Answer 22

Hosting is a service through which storage and computing services are provided to an individual or organisation for storage and maintenance of 1 or more websites.

Question 23

Identify 3 tasks carried out by a router

Answer 23

-Converting packets from one protocol to another
-Transmitting packets
-Identifying the most effective path to the destination

Question 24

What does the Cloud do?

Answer 24

Remotely hosts resources that can be accessed through the internet

Question 25

Give at least 2 advantages of the Cloud

Answer 25

-You can access data in the cloud from anywhere as long as you have an internet connection -It is environmentally friendly because it reduces the need for single-use storage devices such as CDs -Makes it easier to share files with other users -It is easy to add additional storage -The cloud storage provider will provide a backup in case your files are lost so money doesn't have to be spent on staff and hardware or software -The Cloud provider is responsible for providing security so money doesn't have to be spent on staff and hardware or software -May be low cost and specialised skills aren't required as specialised staff don't need to be employed -Cheaper as it doesn't require already owned infrastructure

Question 26

Give at least 2 disadvantages of the Cloud

Answer 26

-Cannot access files if there is no internet connection -You are not in control of security procedures and reliant on third party (but firms could still be legally responsible) -Reliant on third party for back up connection -Data stored in the Cloud will be vulnerable to hacking and other threats, which the user has no control over -There are issues regarding data ownership -Implications of the 2018 Data Protection Act

Question 27

Define a server

Answer 27

A device that provides services to clients.

Question 28

Define a client

Answer 28

A device that requests access to a service provided by a server

Question 30

What is a star topology?

Answer 30

Each computer system is connected to a central device (hub or switch)

Question 31

What are the advantages of a star topology?

Answer 31

- **Improved security** as data packets are sent directly to and from the central device and not necessarily to all devices - **Easy to add new systems** as they can be attached directly without the network needing to be shut down - **Fast transfer speeds** as there are minimal network collisions -If a single cable breaks only that computer is affected

Question 32

What are the disadvantages of a star topology?

Answer 32

- **Central device required** to be purchased, installed and maintained - If the **central device fails, the whole network will fail**

Question 33

What is a mesh topology?

Answer 33

Each computer system is connected to every other computer system

Question 34

What are the advantages of a mesh topology?

Answer 34

- **Not reliant on central node**: If one cable or system fails, data packets can take an alternative route - **Can withstand large amounts of data traffic** due to the large possible number of routes and connections - **New systems can be added without disrupting the entire topology**

Question 35

What are disadvantages of a mesh topology?

Answer 35

- Large amount of cables mean it can be expensive to install and maintain -Redundant cabling