unit 2 Flashcards
1
Q
7 benefits of a LAN
A
users can share peripherals such as printers, shared access to internet, can access filed from any computer on network, communication made easier via social networks, centralised databases to share files easily, servers can be used to provide centralised backups, updated and security, media streaming
2
Q
drawbacks of LAN
A
increases security risk to data, malicious software can infiltrate networks, servers and switches can provide a centralised point of failure, factors can impact performance of the network
3
Q
what is a peer to peer network
A
when computers are all equal to other computers. There is no server providing services.
4
Q
what will each peer on a peer to peer network have
A
their own printer, provide access to their own files
5
Q
what is each peer on a peer to peer network responsible for
A
their own backups, their own security, carrying out their own backups
6
Q
advantages of a peer to peer network
A
easy to set up and maintain, cheap as there is no expensive hardware to purchase, no specialist knowledge or staff required
7
Q
disadvantages of peer to peer network
A
users need to manage their own backups, users need to manage their own software updates, network can be less secure
8
Q
what is a client server network
A
where computers on a network connect to a server via a switch
9
Q
what is a server
A
a computer on a network that often has a single purpose
10
Q
server purposes
A
managing access to the internet, managing printers, providing email services, providing backups, controlling security
11
Q
what is more powerful server or client machines
A
server
12
Q
what type of hardware and software to servers have
A
specialist
13
Q
what is a network that uses a server called
A
client- server model
14
Q
advantages of a client server network
A
managing backups is easier as it is done from a central point, updating and installing software can be done from a central point, security of files can be manages easily
15
Q
disadvantages of a client server network
A
expensive to purchase setup and maintain, specialist network manager required, servers can be a single point of failure
16
Q
what type of waves does satellite communication use and what for
A
radio waves for wireless communication
17
Q
what happens to signals in satellite communication
A
they are sent between satellite and ground station on earth. Ground stations transmit the radio waves to antenna with in or connected to a digital device
18
Q
advantages of satellite communication
A
always available
19
Q
disadvantage of satellite communication
A
can be interrupted by weather conditions, signals do not pass through solid objects
20
Q
what does DVB stand for
A
digital video broadcasting
21
Q
what does DVB-S stand for
A
digital video broadcasting satellite
22
Q
how does satellite television work
A
a video signal is sent from the broadcaster to a satellite, and sent back to earth to can antenna connected to a set-top box or directly to a TV
23
Q
what does a set-top box or TV do to a satellite signal
A
decodes it to make it watchable
24
Q
what are DVD-T and DAB methods of
A
transmitting video and audio signals from transmitters to an antenna
25
how does DAB and DBV-T work
transmitters bases on earth transmit a signal to an antenna, once received signals travels through wires to a receiver which decodes the signal
26
advantages of digital television and radio
improved quality, access to more channels
27
what is high definition multimedia interface (HDMI) used for
high definition video and audio signals
28
what is sony/phillips digial interface format (S/PDIF) used for
transmit digital audio between devices
29
what is a mini-jack used for
connect headphones, speakers and microphones to devices
30
what is ethernet used for
connecting devices to a LAN
31
what is a USB used for
connecting and powering various devices such as printers, flash drives keyboards, mice etc
32
what is WI-FI used for
a wireless method of connections devices to a LAN
33
what is Bluetooth used for
connects devices over short distances
34
what is infra-red used for
transmits very small amounts of data over short distances
35
what is near field communication used for (NFC)
close proximity radio frequency identification
36
what is 4G and 5G used for
provides internet access to mobile devices
37
what is a LAN
network with a small geographical area
38
who is all the hardware owned by in a LAN
company/organisation using it
39
advantages of LAN
centralised management of updates, backups and software installations, secure devices with use of firewalls, anti virus software and other security features, users share resources, users can collaborate and share files and folders
40
disadvantages of LAN
if hardware fails the network may not function, networks more prone to attacks, network traffic can make access to data slow, require maintenance
41
what is a WAN
network with a large geographical area, they are a collection of LANs joined together
42
how are computers on a WAN connected
routers
43
who is the hardware owned by on a WAN
not all by the company/organisation using it
44
what do WANs use to connect LANs together
fibre optic cables, telephone lines and satellite
45
what is PAN used for
transmission of data between devices in a close proximity
46
what is the range of of a PAN
very short
47
devices that make use of a PAN
wireless headphones, mobile phones, tablet, laptop etc
48
what is tethering
when a host device shares its internet connection with other connected devices
49
when is tethering commonly used
by mobile devices to share its mobile data connection to devices such as laptops
50
what do some network providers charge for tethering
extra
51
what is WIFI
a common standard for wireless networks. It connects devices. They can communicate with a hotspot or with a wireless access point
52
when would WIFI be preferred over Bluetooth
when high speed of data transfer is required, long range communication, many devices needed to be connected at the same time
53
advantages of WIFI
portability, low cost, compatibility
54
disadvantages of WIFI
slower data transfer than ethernet, less secure than ethernet, range
55
what is Bluetooth
another common standard for wireless networks
56
what devices does bluetooth connect
headphones, controllers, keyboards and mice
57
what type of connection is bluetooth used for
direct connections between devices
58
what happens to bluetooth device when they pair (encryption)
they generate a cryptographic key. The keys are used to generate a secret shared key which is then used to encrypt data between the 2 devices and create a wireless personal area network. Connected devices continuously change their transmitting frequency between 79 different channels to avoid interference
59
what is it called when Bluetoothed devices constantly change frequency
frequency hopping spread spectrum (FHSS)
60
Bluetooth advantages
compatibility, low power consumption
61
bluetooth disadvantages
speed, data can be intercepted, short range
62
what is GPS (global positioning system)
satellite system used to track exact location of an object. Satellites orbit to receive, amplify and transmit signals. Radio frequencies are used to communicate between satellites and ground stations.
63
what does GPS require
direct line of sight
64
GPS advantages
wide coverage, real time, improved communication in remote locations, accurate
65
GPS disadvantages
expensive to setup and maintain, signal interference due to weather or obstacles, limited bandwidth and capacity, privacy concerns - potential for surveillance
66
what do 3G and 4G do
provide mobile devices with access to the internet
67
what does each new generation of mobile data networks have
faster transfer rate and improved capacity for users
68
what does 3G and 4G reference
generation of mobile data networks
69
what is infrared
wireless communication method used to transfer very small amounts of data to a device in a direct line of sight
70
what devices is infrared commonly used in
televisions, audio receivers, home entertainment equipment
71
what type of waves does infra-red use and what does this cause
light waves - walls or obstacles block signal, sunlight affects signal
72
why is infra-red good
is is reliable and cost effective for short range wireless communication needs
73
what is NFC
a subset of RFID which allows communication between 2 devices in a very close proximity
74
what 2 things can NFC be
passive - uses energy from the reader, active- has its own power source
75
what type of NFC to smartphones use for contactless payments
active
76
what can smartphones also do using NFC
exchange data
77
advantages of NFC
convenient, secure, fast, low power consumption
78
disadvantages of NFC
limited range, not suitable for transferring large files, compatibility
79
what is bandwidth
amount of data that can be carried by a connection in 1 second
80
what is bandwidth measured in
bites per second
81
what would less bandwidth cause a network to do
slow down
82
what does a higher bandwidth mean
more data can be sent and received in one second
83
what can a higher bandwidth improve
upload and download speeds, online gaming, streaming high definition video
84
how does streaming work
enough data to play a few seconds in downloaded and stored temporarily in the buffer, as the video plays more data is downloaded at the same time.
85
what happens if the buffer becomes empty when streaming
play back will pause
86
what must happen to stream successfully
data must be downloaded into the buffer at a faster rate than it is being emptied
87
what is latency
delay between data being sent and received
88
what does a high latency cause
more data will be on the network causing collisions, this causes error rate to increase
89
what type of bandwidth does smooth online gaming require
high
90
what will a high latency cause when online gaming
lag and the game will not respond as quickly to user commands
91
why is a high latency an issue when online gaming
other players will have a faster response time (advantage) due to lower latency
92
what happens when streaming with a high latency
micro-stutters which ruins the users watching experience
93
what factors affect speed and volume of data transfer
interference, transfer method, blockages, distance
94
how can interference be caused
devices that emit electromagnetic signals such as microwaves and fridges can disrupt signals
95
why does wired have a higher bandwidth than wireless
they can carry more frequencies
96
how do blockages affect data transfer
walls and furniture can block signals - lowering the bandwidth available
97
how does distance affect data transfer
the strength of a wired and wireless signal reduces as data has to travel further
98
wired vs wireless speed
wires faster
99
wired vs wireless portability
in wired location is limited by a cable, in wireless only by range
100
wired vs wireless security
wired has better physical security, wireless is easier to intercept data
101
wired vs wireless range
wired less affected by interference, wireless affected by interference
102
wired vs wireless safety
cables can be trip hazards, need routing along walls, under floors
103
wired vs wireless cost
cables are cheap, wireless needs wireless access point to be purchased
104
what do internet service providers provide
access to high speed internet (broadband)
105
what do internet service providers use to create a WAN
fibre optic or copper cable
106
what is fibre optic
cable that used light to transmit data on a WAN
107
fibre optic compared to copper cables
fibre optic transmits data at a much higher speed and has a much hugher bandwidth
108
why is fibre optic the best option to send sensitive data
does not suffer from interference
109
fibre optic cables and distance
they can cover a long distance without any degradation
110
copper cables and range
copper cables degrade over time which limits their range
111
copper cables and interference
they suffer from interference which can disrupt data quality
112
copper cable speed
they transmit data at a much slower rate, and have a lower bandwidth compared to fibre optic
113
what are passwords
a digital lock to prevent unauthorised access to an account. They are used to authenticate a user to a network
114
how are passwords stored in a database and why
encrypted/ciphered so that if a hacker gained access they would't be able to gain passwords of users
115
what is important to maintain security (passwords)
strong passwords and regular password changes
116
what is a firewall
a barrier between a network and the internet
117
what does a firewall do
prevents unwanted traffic from entering a network by filtering requests to unsure they are legitimate
118
what 2 things can a firewall be
hardware and software
119
what do hardware firewalls do
protect the whole network and prevent aunauthorised traffic
120
what do software firewalls do
protect individual devices on the network, monitoring the data going to and from each computer
121
what is encryption
a method of scrambling data, so that unauthorised users cannot understand it
122
what do encryption methods uses to scramble or unsramble data
keys
123
what does encryption use to scramble data
complex mathematical algorithms
124
what are the 2 types of encryption
symmetric and public key
125
how does symmetric encryption work
The sender uses a key to encrypt the data before transmission. The receiver uses the same key to decrypt the data. It's usually faster making it ideal for large amounts of data
126
what is the downside of symmetric encryption
the challenge of securely sharing the key between sender and receiver. If an unauthorises users captures the key, they can decrypt all messages
127
how many keys does public key encryption use
2
128
what are the 2 keys that public key encryption uses
public key - for encryption, private key - for decryption
129
how does public key encryption work
receivers openly share their public key. Senders use this public key to encrypt the data. The receiver's key is the only key that can decrypt the data and is kept locally on their side. Public and private keys are designed to work together
130
which type of encryption is fastest
symmetric
131
what type of data transactions is public key encryption used for
more secure and smaller ones (passwords, bank details)
132
what is wireless encryption protocol (WEP)
a method of encrypting data being transmitted on a wireless network
133
how does wireless encryption protocol work
each device on the network uses the same key to encrypt and decrypt data. It is a less secure encryption method because all devices on the network share the same key.
134
what type of software can be used to identify the key used in wireless encryption protocol
eavesdropping software
135
what is WIFI protected access (WPA)
a more secure method of encrypting data being transmitted on a wireless network
136
how does WIFI protect access work
each device connected to the network receives a different key. New keys are used for every packet transmitted on the network.
137
what does a VPN do
allows users to remotely connect to LANs. All data sent and received using a VPN in encrypted
138
common uses of VPNs
remotely accessing a network, making secure payments, hiding web activitie, bypassing geographical rights or online cencorship
139
what are file access rights
determine different levels of access to specific files/folders
140
examples of file permissions
read, write, (edit) delete, execute ( run applications)
141
what is a transaction log
a secure file on a network that keeps a record of every action performed by devices on a network
142
what do transaction logs include
device and data access, timestamps, user IDs, successful/failed login attempts
143
what do transaction logs do and not do
dont directly protect a network, they help administrators monitor any unusual activity
144
what is another indirect method of protecting a network
backups
145
what is a backup
keeping copies of data in a secure place on the network, in the event of a data breach/loss
146
what is an IP (internet protocol) address
unique identifier given to devices which communicate over the internet
147
how can IP addresses be allocated
by a network administrator or assigned dynamically by a dynamic host protocol server (DHCP)
148
what do IP addresses make possible
delivering data to the right device
149
what happens to the IP address of a device when it moves to a different network
it changes
150
how is IPv4 represented
represented as 4 blocks of denary numbers between 0 and 256, separated by full stops. Each block is one byte.
151
how is IPv6 represented
represented as 8 blocks on hexadecimal digits, seperatd by colons
152
how much data is a IPv6 address
each block is 2 bytes, each address is 16 bytes
153
how much data is an IPv4 address
each block in 1 byte, each address is 4 bytes
154
what is a MAC address
universally unique identifier given to devices which communicate over a LAN
155
do MAC addresses change
no
156
what do MAC addresses make possible
for switched to efficiently forward data to the intended recipient
157
how is a MAC address assigned
to any device that have a network interface card (NIC) during manucfactoring
158
how is a MAC address represented
12 hexadecimal digits (48 bits). The first three pairs are the manufacturer ID number and the last 3 are the serial number of the NIC
159
what can MAC addresses be used for
restrict or allow access to a network, identify a device on a network, track a device, assign IP addresses
160
what does a device name help to do
identify devices on a network
161
how are device names set
by users or from a router
162
what is a wired network
where physical cables are used to join devices together and transmit data
163
what are the common type of cables in a wire network
ethernet, fibre optic
164
what is ethernet
a wired networking standard to carry electrical signals between devices on a LAN
165
what cables does ethernet use
twisted pair cables (CAT5) to allow duplex communication
166
where is ethernet most common
in offices and homes to connect devices and servers
167
what does a wireless access point (WAP) allow
allows wireless devices to connect to a LAN. The WAP connects to a switch or hub via an ethernet cable
168
what can you do to overcome limited WAP range
use multiple WAPs
169
what is a router responsible for
routing data packets between differnt networks
170
what does the router do to data traffic
manages and priortrises it
171
what assigns IP addresses to devices on a network
router
172
what does a router act as
a gateway
173
what is a gateway
device that bridges the connections between 2 different types of network
174
what do gateways translate between
different network protocols
175
what does a switch allow
multiple wired devices to connect to a LAN
176
what type of device is a switch and what does this mean
active device - can inspect network data and route it to the correct device, reducing network traffic
177
what can extra software in a switch do
allow administration/configuration
178
what is a booster
device used to amplify a network signal in order to extend the normal range
179
can boosters be uses with both wires and wireless networks
yes
180
can wireless access points be configured to act as a booster
yes
181
what is a server
dedicated computer that shares its resources with devices that connect to it
182
what are devices that connect to a server known as
clients
183
server examples
file, web, print, authentication, application
184
what does a file server do
allows access to shared and private resources
185
what does a web server do
stores the content of websites and processes requests made
186
what does a print server do
manages print jobs and organises them so that individual printers and not over loaded
187
when does an authentication server do
stores usernames and passwords so they can be check when a user logs in, authenticated users receive a certificate that allows them to access resources
188
what does an application server do
allows clients access to applications that run directly from the server
189
a singles computer can perform multiple server functions depending on its resources
190
what is a web browser
software application used to locate, retrieve, and display content on the world wide web. Displays web pages
191
features of web browsers
home page, ability to bookmark, history of viewed websites, hyperlinks
192
what is an internet service provider (ISP)
a company that provides access to the internet to users and businesses
193
what do ISPs charge
subscription fee
194
what are search engines
tools that locate and display web pages related to the search terms entered by the user
195
what are search engines essential for
navigating the vast amount of information on the internet
196
how to search engines rank the relevance of each page to the search terms
they index millions of web pages and use algorithms
197
3 stages of search engines
crawling, indexing, ranking
198
what is crawling in web browsers
they scour the internet daily to retrieve new websites
199
what is indexing in web browsers
how websites are categorised based on the content of their webpages- key words and metadata
200
what is ranking in web browsers
how websites are ranked and listed bases on search engine pages
201
what is filter software
uses 2 lists stored in a database to allow or block access to websites. URLs entered by a user are compared against both lists
202
what are the 2 lists in filter software
whitelist - URLs on the whitelist are allowed and the website can be viewed
Blacklist - URLs on the blacklist are not allowed and the website is blocked
203
what happens to URLs that are not found in the database of filter software
they are allowed
204
who and why uses filter software
schools and parents - to prevent children from accessing age inappropriate content
205
what can administrators do to the lists of filter software
add or remove URLs
206
