1.3.3

Question 1

network

Answer 1

connecting at least one computing device to another, either via cable or wireless

Question 2

advantages of networks

Answer 2

Users can share files
Users can share peripherals and connections to other networks such as the internet
Users can access files from any computer on the network
Servers can control security, software updates and backup of data
Communication with other people – e.g., email and social networking

Question 3

disadvantages of networks

Answer 3

Increased security risks to data
Malware and viruses spread very easily between computers
If a server fails, the computers connected to it may not work
Computers may run slower if there is a lot of data travelling on the network

Question 4

standards

Answer 4

a set of hardware and software specifications that allow manufacturers to create products and services that are compatible with each other

Question 5

protocols

Answer 5

if 2 devices share the same protocol, they can exchange information

Question 6

common protocols

Answer 6

TCP - Communication over LAN/WAN
IP - Communication over LAN/WAN
UDP - Communication over LAN/WAN
HTTP - Web page requests
HTTPS - Web page requests
FTP - File tansfers
POP - Email
IMAP - Email
SMTP - Email

Question 7

importance of protocols and standards

Answer 7

most devices wouldn’t be able to interact or communicate with one another

Question 8

TCP/IP stack vs UDP

Answer 8

Transmission Control Protocol - provides error-free transmission between two routers

Internet Protocol - routes packets across a WAN

TCP + IP make the stack that is foundation for communication over the internet

User Datagram Protocol - uses a simple, connectionless transmission model
used to send short messages using datagrams, where speed is more important than accuracy
an alternative to TCP but has no error checking

Question 9

HTTP(S)

Answer 9

Hypertext Transfer Protocol - a way for a client and server to send and receive requests and deliver HTML web pages
the fundamental protocol of the WWW

Hypertext Transfer Protocol Secure - HTTP, except it adds in encryption and authentication

Question 10

FTP

Answer 10

File Transmission Protocol - used for sending files between computers, normally on a WAN

Question 11

POP/IMAP/SMTP

Answer 11

Post Office Protocol - retrieves emails from a mail server and transfers them to your device, removing them from the server in the process

Internet Message Access Protocol - keeps emails on the mail server, maintaining synchronicity between devices

Simple Mail Transfer Protocol - transfers outgoing emails between servers and from email clients to servers

Question 12

the internet

Answer 12

the most well-known WAN
a collection of interconnected networks, routers, cables, satellites and other hardware spanning the world

Remember, the internet is not the same as the World Wide Web, which is just a service on the internet

Question 13

WWW

Answer 13

a service on the internet

Question 14

DNS

Answer 14

Domain Name System - turns domain names into IP addresses, which browsers use to load internet pages

Question 15

protocol layering

Answer 15

to divide the complex task of networking into smaller, simpler tasks that work in tandem with each other
hardware and/or software for each layer has a defined responsibility, and each one provides a service to the layer above it

Question 16

advantages of layering

Answer 16

Reducing a complex problem into smaller sub-problems
Devices can be manufactured to operate at a particular layer
Products from different vendors will work together

Question 17

4 main TCP/IP protocol layers

Answer 17

Application
Transport
Network
Link

Question 18

application layer

Answer 18

Network applications such as web browsers or email programs operate at this layer
uses an appropriate protocol relating to whatever application is being used to transmit data

Question 19

tansport layer

Answer 19

Sets up communication between two hosts – they agree settings such as language and packet size

Question 20

internet/network layer

Answer 20

Addresses and packages data for transmission
Routes packets across the network

Question 21

link layer

Answer 21

Network hardware and connection port standards
Operating system device drivers also sit here
Facilitates the transmission of binary via any media

Question 22

LANS

Answer 22

Local Area Network - a network that covers a small geographical area, typically located on a single site

All the hardware for a LAN tends to be owned and controlled by the organisation using it

LANs are typically connected using: UTP cable, Fibre optic, Wi-Fi

Question 23

WANS

Answer 23

Wide Area Network - a network that covers a large geographical area

When multiple LANs physically located in different areas are connected, they form a WAN

The infrastructure that connects LANs to form a WAN is leased from telecommunication companies who own and manage it

WANs are typically connected by: Telephone lines, Fibre optic cables, Satellite links

Question 24

circuit switching

Answer 24

provides the basis for traditional telephone networks
creates a temporary and dedicated link of fixed bandwidth between the source and destination that only lasts until the transmission is complete
guarantees the quality of the transmission through dedicated bandwidth, making circuit switching excellent for data that needs a constant link end-to-end such as real-time video
however a lot of the potential bandwidth can be wasted

Question 25

packet switching

Answer 25

breaks streams of data into smaller blocks, each sent independently of one another
at each node, packets are sent via whichever route the node decides is the least congested – this maximises bandwidth but doesn’t guarantee the quality of the transmission
packets can take different routes to their destination and may arrive out of order
more affordable and efficient than circuit switching as all bandwidth can be used at once
requires less complex infrastructure and can easily respond if parts of the network fail

Question 26

network threats

Answer 26

viruses
worms
hackers
denial of service
data interception
phishing
spyware

Question 27

network security

Answer 27

The aim of network security is to:
Only allow authorised users access to what they need
Prevent unauthorised access
Minimise the potential damage caused by unauthorised access

Question 28

virus

Answer 28

pieces of code capable of copying themselves and spreading throughout a system
typically designed to corrupt a file system or destroy data

Question 29

spyware

Answer 29

a form of malware that covertly obtains information about a user’s computer activities by transmitting data from their device

Question 30

denial of service attack

Answer 30

when an attacker floods a server with useless traffic, causing the server to become overloaded
(past attacks exploited limitations of the TCP/IP stack)
attacks often target web servers of high-profile organisations such as banks, large-scale e-commerce businesses and the government
attacks do not typically result in the theft or loss of data or other assets, they can cost a great deal of time and money to handle

Question 31

anti malware

Answer 31

software to prevent/minimise the impact of malware

Question 32

proxies

Answer 32

a physical device placed between a network and a remote source
all traffic travels through the device on its way in and out of a network
looks at the page and its contents and choose whether to pass it back to the user or not

ensures there is no direct, physical connection between a single user and a remote source

Question 33

encryption

Answer 33

turning plain text into an unreadable form
encrypted using an algorithm and a unique key
you can only translate it with the appropriate key
(won’t stop you from being hacked, but it will make any stolen data very difficult to read)

Question 34

firewalls

Answer 34

a piece of software or hardware (sometimes both) configured to let only certain types of traffic through it by blocking certain ports and types of traffic
it can also inspect data travelling across it to see if it looks suspicious

Question 35

network hardware

Answer 35

Modem
Router
Cable
Network interface controller (NIC)
Wireless access point (WAP)
Hub
Switch

Question 36

modem

Answer 36

transforms digital info from your computer into analogue signals to be transmitted through wires an vice versa
most modems have 2 ports:
One that connects to the outside world.
An Ethernet port that connects to a computer or router

Question 37

router

Answer 37

mainly responsible for routing data:
Between devices on a small home network.
Between devices on a network and the internet.
modems connect to one port on the router, often labelled WAN. Your devices connect to the other ports or wirelessly using the Wi-Fi standard

Question 38

DoS vs DDoS

Answer 38

DDoS (distributed denial of service) attack occurs when multiple systems orchestrate a synchronised DoS attack against a single target

Question 39

cables - types

Answer 39

The 3 most popular are:
Twisted pair
Coaxial
Fibre optic

Question 40

SQL

Answer 40

a code injection technique used to attack data-driven applications
designed to exploit vulnerabilities in poorly coded database applications
code is entered into input text boxes and is then executed by the server

Question 41

cables - twisted pair

Answer 41

made of a pair of insulated copper wires
can be affected by noise from external magnetic fields, but most affordable
Only able to provide low bandwidth, generally used for telephone networks, data networks and cable shielding

Question 42

cables - coaxial

Answer 42

made of 4 cylindrical components – (in to out) solid conductor wire, insulation, grounding conductor, exterior insulation
can be affected by noise from external magnetic fields but to a lesser extent than twisted pair
moderate bandwidth, but more expensive than twisted pair but cheaper than fibre optic
used for feedlines that connect radio transmitters and receivers to antennas, as well as computer network connections, digital audio and cable television

Question 43

cables - fibre optic

Answer 43

made of very thin optical fibres bundled together into a single cable (glass or plastic)
the highest noise immunity, as the light rays are unaffected by electrical noise
high bandwidth capabilities, most expensive
used to support long-distance connections between cities and countries, as well as data centres and organisations transmitting large volume of data

Question 44

NIC

Answer 44

Network Interface Controller
connects a computer to a network
allows wired and wireless communications between computers on a LAN or connected to a large-scale network using the Internet Protocol
a physical layer and data link layer device, providing the necessary circuitry for physical layer processes and some data link layer processes to run on it

Question 45

hub

Answer 45

allows you to connect multiples devices to 1 network
operates on the physical layer and considered a passive device (clarifier)
con - the network can easily become flooded with unnecessary traffic
purely a hardware device
typically slower than switches in terms of data transfer

pd - broadcasts transmissions it receives to all connected devices

Question 46

switch

Answer 46

allows you to connect multiples devices to 1 network
operates on the data link layer and is an active device (clarifier)
A switch typically has software installed on it for administration and configuration purposes.
Switches are typically much faster than hubs in terms of data transfer.

ad - inspect transmission & route them to right device keeps traffic low

Question 47

WAP

Answer 47

Wireless Access Point
a device that creates a wireless local area network (WLAN)
connects to a wired router/switch/hub via an Ethernet cable and projects a Wi-Fi signal within a designated area

Wi-Fi range is limited and easily interrupted by various construction materials, so most businesses use multiple WAPs for full coverage.

Question 48

client-server - pros

Answer 48

Easier to manage file security.
Easier to back up shared data.
Easier to install software updates to all computers.

Question 49

client-server - cons

Answer 49

Can be expensive to set up and maintain.
Requires IT specialists to maintain.
The server is a single point of failure.
Users will lose network access if the server fails.

Question 50

client-server

Answer 50

Controls access and security for a shared file store.
Manages access to the internet.
Manages printing jobs.
Provides email services.
Runs regular backups of data.

Question 51

client-server

Answer 51

Controls access and security for a shared file store.
Manages access to the internet.
Manages printing jobs.
Provides email services.
Runs regular backups of data.

Question 52

peer-to-peer

Answer 52

A peer is a computer connected to the network.
A peer is equal to all other peers.
Peers serve their own files to each other.
Each peer is responsible for its own security and data backup.
Peers usually have their own printers.
Peers can send print jobs to another peer to process, but that peer must be switched on to communicate with the printer.

Question 53

peer-to-peer - pros

Answer 53

Very easy to maintain.
Specialist staff are not required.
No dependency on a single computer.
Cheaper to set up.
No expensive hardware.

Question 54

peer-to-peer - cons

Answer 54

The network is less secure.
Users will need to manage their own backups.
Can be difficult to maintain a well-ordered file store.

Question 55

ISP

Answer 55

internet service provider