You can print this page for a quick reference guide or you can use the tools below to create printable test sheets
4.1.1: understand why computers are connected in a network
Keyword
Definition
cloud storage
where people can access remote storage devices to save/load more data than their local computer is capable of storing
collaboration
where more than one person can work on the same document at the same time
communication
where people can send messages to each other over a network connection
computer system
hardware and software which allows programs to be run
connection
link between two computers
network
two or more computers connected together to share data
4.1.2: understand different types of networks (LAN, WAN)
Keyword
Definition
Local Area Network
where computers are connected together that are physically close together
Wide Area Network
where computers are connected together that are spread out over a large physical area
4.1.3: understand how the internet is structured (IP addressing, routers)
Keyword
Definition
destination address
IP address of the computer which should receive data
IP address
sequence of numbers which specifies the location of a computer on the Internet
router
a device with multiple network connections which sends passes on network traffic so that it can eventually reach the right destination
routing table
used by routers to work out which network connection to use to forward network traffic so that it reaches the right destination address
source address
IP address of the computer which sends data
The Internet
international, interconnected network of networks
4.1.4: understand how the characteristics of wired and wireless connectivity impact on performance (speed, range, latency, bandwidth)
Keyword
Definition
bandwidth
the maximum possible amount of bits per second a network can achieve if there was no latency or collisions
Bluetooth
way of connecting wireless networks between personal devices
collision
when multiple computers attempt to send data at the same time over the same network connection or wireless frequency
copper cable
way of connecting wired networks which is relatively cheap but slow
fire optic
way of connecting wired networks which is relatively expensive but fast
latency
the amount of time you have to wait after sending a request over a network before you receive a response
network performance
a measure of how fast and responsive a network is
NFC
way of connecting wireless devices over small distances such as contactless payment cards
range
the distance a computer can move before it is no longer able to connect to the network
RFID
way of sending small amounts of data over small distances to identify products or people
speed
the actual number of bits per second that is transferred over a network
wired connectivity
being able to connect to a network using a physical connection (e.g. ethernet / fibre optic)
wireless connectivity
being able to connect to a network without a physical connection (e.g. bluetooth / WIFI)
Zigbee
way of connecting wireless devices to a mesh network without needing WIFI
4.1.5: understand that network speeds are measured in bits per second (kilobit, megabit, gigabit) and be able to construct expressions involving file size, transmission rate and time
Keyword
Definition
download time
the number of seconds a file takes to be sent from a server to your computer
file size
the number of bytes needed to store a file
gigabit
1,000,000,000 bits
kilobit
1,000 bits
megabit
1,000,000 bits
transmission rate
the number of bits that is transferred over a network every second
upload time
the number of seconds a file takes to send from your computer to a server
4.1.6: understand the role of and need for protocols (Ethernet, Wi-Fi, TCP/IP, HTTP, HTTPS, FTP and email (POP3, SMTP, IMAP))
Keyword
Definition
Ethernet
network protocol for wired networks
FTP
network protocol used to transfer files across a network
HTTP
network protocol used to transfer data over the WWW such as viewing web pages
HTTPS
network protocol used to transfer encrypted data securely over the WWW such as logging into web pages
IMAP
email protocol for accessing messages stored on a network server
IP
network protocol used to route packets of data across a network to the correct destination
network protocol
set of rules computers must follow in order to allow them to transfer data
POP3
email protocol for downloading messages from a network on to your own computer
SMTP
email protocol for sending messages over a network
TCP
network protocol used to split data into packets and ensure they arrive and can be reassembled in order
TCP/IP
network protocols used for the Internet
WiFi
network protocol for wireless networks
4.1.7: understand how the 4-layer (application, transport, internet, link) TCP/IP model handles data transmission over a network
Keyword
Definition
application
highest level of the TCP/IP protocol stack which determines how programs request and send data over a network (e.g. HTTP)
internet
second lowest level of the TCP/IP protocol stack which determines how packets are routed to the right destination over a network (e.g. IP)
layer
level of abstraction in a model of how different devices communicate over a network
link
lowest level of the TCP/IP protocol stack which determines how individual bits and bytes are sent over a network (e.g. Ethernet / WiFi)
network protocol
set of rules which determine how computers communicate over a network
TCP/IP
transfer control protocol and internet protocol
transport
second highest level of the TCP/IP protocol stack which determines how data is split into packets and reassembled in the correct order (e.g. TCP)
4.1.8: understand characteristics of network topologies (bus, star, mesh)
Keyword
Definition
bus topology
way of connecting computers to a network where all devices are linked with one main cable.
hub
device at the centre of a star topology network which forwards network traffic to all connected devices
mesh topology
way of connecting computers to a network where some or all devices are connected to each other directly
star topology
way of connecting computers to a network where each device is connected to a central hub or switch
switch
intelligent device at the centre of a star topology network which routes traffic to the right connected device
terminator
device at both ends of the shared cable in a bus topology network which stops data bouncing back down the cable
4.2.1: understand the importance of network security, ways of identifying network vulnerabilities (penetration testing, ethical hacking) and methods of protecting networks (access control, physical security, firewalls)
Keyword
Definition
access control
limiting the rights of specific groups or individual users so that you can control what they can and can't do
ethical hacking
obtaining permission to identify security vulnerabilities on a computer network and then reporting them responsibly so that they can't be exploited by malicious hackers
firewall
using a set of rules to filter network traffic to block data from malicious sources or to allow data from trusted sources
malicious hacker
someone who breaks into a network or computer system without permission
penetration testing
attempting to break into a network using a list of common vulnerabilities in order to find out if there are any possible ways to gain unauthorised access
physical security
limiting how close people can get to a computer system by using locks, biometrics or locking down devices
vulnerability
a weakness in network security which could allow unauthorised users to gain access
