1.3 Computer Networks, Connections & Protocols

Question 1

Local Area Network (LAN)

Answer 1

A network that covers a small geographical area.
All hardware for a LAN is owned by the organisation using it. E.g. School
LANs can be wired (UTP cables, fibre optic) or wireless (Wi-Fi).

Question 2

Wide Area Network (WAN)

Answer 2

A network that covers a large geographical area, connecting LANs together.
The Internet is a WAN, some infrastructure is owned by someone else e.g. telecommunication companies, ISPs.
WANs are connected with telephone lines, fibre optic cables or satellite links.

Question 3

Client-Server Network

Answer 3

Every device is either a client or server.
A client establishes a connection with the server over the network.
Servers can backup and store data centrally, however can be expensive and difficult to run.

Question 4

Peer-to-Peer Network

Answer 4

This network configuration has no central server.
Each computer is equal in responsibility and each has the ability to work as both a client and a server.

Question 5

Bandwidth

Answer 5

The maximum amount of data that can be sent and received successfully in a given time.

Question 6

Latency

Answer 6

The delay from transmitting data to receiving it.

Question 7

Transmission media

Answer 7

Wired connections, particularly fibre optic, have a higher bandwidth than wireless connections.

Question 8

The number of users

Answer 8

Too many users or devices on the same network can cause the network to slow down if there is insufficient bandwidth for the data.

Question 9

Error rate

Answer 9

A greater number of errors that occur when data is transferred, means the data has to be resent until it arrives correctly.

Question 10

Network Interface Controller/Card (NIC)

Answer 10

Connects a device to a wired or wireless network. All have a hardcode unique identifier called a MAC address.

Question 11

Wireless Access Point (WAP)

Answer 11

Allows wireless enabled devices to connect to a network without cables.

Question 12

Switch

Answer 12

Forwards packets between devices in other segments of a LAN. Uses MAC Addresses.

Question 13

Router

Answer 13

Forwards packets between networks. Needed to connect a LAN to a WAN. It uses an IP address to route traffic.

Question 14

Transmission Media - Copper Cables (UTP)

Answer 14

Data is transmitted through these using electrical signals, with insulation to reduce interference.
Copper cable is cheap and easy to install.

Question 15

Transmission Media – Fibre Optic Cables

Answer 15

Data is transmitted through light.
Low latency and cover long distances – Expensive.

Question 16

DNS (Domain Name Server)

Answer 16

Converts a website address (URL e.g. www.google.co.uk) into an IP address (e.g. 172.217.14.195) for routers.

Question 17

Hosting

Answer 17

The storing of websites on domain name servers.
The World Wide Web (WWW) is the collection of web pages hosted on these servers. A hosting company will provide 24/7 access, high bandwidth connections and security.

Question 18

The Cloud – Remote Service Provision

Answer 18

Servers that store data and programs remotely that can be accessed and used over the Internet are referred to as cloud servers.

Question 19

Advantages/Disadvantages of the Internet

Answer 19

Access any time & anywhere.
Flexible storage capacity.
Automatic backup.
Do not need to purchase & maintain expensive hardware.
Environmentally friendly.

Need for a reliable Internet connections.
No direct control over the security of your data.
Legal implications: Data Protection Act 2018

Question 20

Star Network Topology

Answer 20

All devices connect into the central switch.

Question 21

Mesh Network Topology

Answer 21

Every device is connected to every other device.

Question 22

Advantages/Disadvantages to Star Topology

Answer 22

A failure of one device does not affect any other devices.
New devices can be added easily to the network.

The whole network fails if the switch fails.

Question 23

Advantages/Disadvantages to Mesh Topology

Answer 23

Messages can be received more quickly.
Messages should always get through as they have many possible routes (backups).

Expensive.
Difficult to set up & establish connections.
Requires a lot of maintenance.
Difficult to expand the network.

Question 24

Wired – Ethernet

Answer 24

The main standard for wired connections is Ethernet.

Question 25

Wireless – Wi-Fi & Bluetooth

Answer 25

Both common standards for wireless networks.
Wi-Fi and Bluetooth both use radio waves.

Question 26

Advantages/Disadvantages to Wired Connection

Answer 26

Usually faster.
More secure than wireless as a hacker would need physical access.

Need to manually set up the cabling.
Hard to add new devices as each will require additional cabling.
Expensive.

Question 27

Advantages/Disadvantages to Wireless Connection

Answer 27

Cheap.
Easy to connect new devices without new hardware.
Better for the environment.

Can be interference, particularly through walls.
Slower and less stable.
More security risks.

Question 28

(Media Access Control) MAC address

Answer 28

A unique hexadecimal identification number assigned to every Network Interface card (NIC) used in network devices.

Question 29

IP Address

Answer 29

Uniquely identifies a device’s connection on a network, and defines where it is located geographically.

Question 30

IPv4 Address

Answer 30

Uses 32 bits to specify an address.
For readability, they are expressed in dotted decimal notation. Example: 69.89.31.212
Each decimal number (between 0 and 255) corresponds to a byte.

Question 31

IPv6 Address

Answer 31

Uses 128 bits to specify an address.
Dotted decimal is too long, so they are expressed in colon hex notation.
8 groups of 16 bits (4 hex digits), separated by colons. Example: 2001:02b8:85a3:0000:8a2e:0370:7334

Question 32

Protocol

Answer 32

A set of rules that govern communication on a network.

Question 33

TCP/IP – Transmission Control Protocol/Internet Protocol

Answer 33

TCP provides an error free transmission between 2 routers.
IP routes packets across a wide area network (WAN).
Together they make up the TCP/IP protocol stack which is the foundation of communication over the Internet.

Question 34

HTTP/HTTPS – Hypertext Transfer Protocol Secure

Answer 34

HTTP is a client-server method of requesting and delivering HTML web pages. It is the fundamental protocol of the World Wide Web (WWW).
HTTPS is the same as a HTTP except it adds in encryption and authentication. Used when a website needs to deal with sensitive information e.g. passwords or bank account details.

Question 35

FTP – File Transfer Protocol

Answer 35

Used for sending files between computers, usually on a wide area network (WAN).

Question 36

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

Answer 36

POP retrieves emails from a mail server. It will remove it from server and transfer to your device.
IMAP is used by mail clients to manage remote mail boxes and retrieved email from a mail server.
SMTP sends emails to an email server.