ch2 Flashcards

1
Q

benefit of networking computers and devices

A

1- devices could be shared
2-licenses to run software on networks are often cheaper than running one for every device
3- data and files are backed up centrally after the end of each day
4- access to reliable data that comes from a central source

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2
Q

drawback of networking computers and devices

A

1- managing a large network can be difficult and a complex task
2- a breakdown in a device can affect the whole network
3- Cabling and servers can be an expensive initial outlay

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3
Q

how does lan become part of wan

A

the computers and devices in a lan are connected to hubs or switches, one of the hubs or switches is connected to a modem or router to allow lan to be part of wan

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4
Q

wirless lan

A

lans that provide wireless communications using infrared or radio signals instead of wires and cables

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5
Q

wireless access point

A

allows devices to access a lan without a wired connection

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6
Q

identify two differences between lan and wan

A

1- wan covers a large geographical area while lan covers a small geographical area
2- lan connections between devices are usually physical, while connection in wan is virtual
3- lan has a high transfer rate while wan has a low transfer rate
4- ownership in lan is private while it can be private or public in wan

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7
Q

what is a mesh topology

A

all computers are connected to at least one other device, it contains multiple routes between devices

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8
Q

advantage of using mesh topology instead of bus topology

A

1- if one route goes down there are more available
2- security is better since it does not use one main line
3- fewer collisions

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9
Q

role of different computers in a thin-client model

A

clients only send requests to the server and display the returned results, server performs all processes required by the tasks and data storage

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10
Q

benefit of using both wired and wireless connections

A

wired provides better performance for the device
There will be less interference if students connect via a cable
Wireless connection means that the students can use their devices in different rooms/ device is portable
Wireless connection enables the students to bring multiple devices

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11
Q

Identify and describe the two parts of an IP address in a subnetwork

A

IP address is made up of a network ID and a host ID:
1- Each device in a subnetwork has the same network ID
2- Every device in each subnetwork has a different host ID

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12
Q

client-server

A

network that uses separate dedicated servers and specific client workstation. all client computers are connected to the dedicated servers

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13
Q

features of client-server

A

1- user is able to access most files which are stored in dedicated servers
2- it allows the installation of software onto a client’s computer
3- the model uses central security databases which control access to the shared resources. (the user must log into the network using password and user ID)

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14
Q

Peer-to-peer

A

network in which each node can share its files with all the other nodes. Each node has its own
data and there is no central server.

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15
Q

thin client

A

device that needs access to the internet for it to work and depends on a more powerful computer for processing

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16
Q

thick client

A

device that can work both on line and off line and is able to do processing even if its not connected to a network/internet

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17
Q

key features of using pee-to-peer model

A

1- all computers are of equal status
2- Each computer provides access to resources and data
3- Computers can communicate and share resources

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18
Q

drawbacks of peer-to-peer model

A

1- reduced security, ach computer is at risk from viruses from other computers
2- No central management of backup, f the data from one computer is not backed up it is lost to all of them
3- Individual computers may respond slower, because they are being accessed by other computers

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19
Q

advantages and disadvantages of thick client

A

advantage:
-more robust (device can carry out processing even when not connected to server)
- clients have more control (they can store their own programs and data/files)
disadvantage:
- less secure (relies on clients to keep their own data secure)
- each client needs to update data and software individually
- data integrity issues, since many clients access the same data which can lead to inconsistencies

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20
Q

advantages and disadvantages of thin client

A

advantages:
- less expensive to expand (low-powered and cheap devices can be used)
- all devices are linked to a server (data updates and new software installation done centrally)
-server can offer protection against hacking and malware
disadvantage:
high reliance on the server; if the
server goes down or there is a break in the communication link then the devices cannot work
- despite cheaper hardware, the start-up costs are generally higher than for thick clients

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21
Q

Network topologies types

A

1- bus
2- mesh
3- star
4- hybrid

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22
Q

bus network topology

A

network using single central
cable in which all devices are connected to this cable so
data can only travel in one direction and only one device
is allowed to transmit at a time. each node looks at each packet and determines whether or not the address of the recipient in the package matches the node
address. If so, the node accepts the packet; if not, the packet is ignored

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23
Q

star network topology

A

a network that uses a central
hub/switch with all devices connected to this central
hub/switch so all data packets are directed through this
central hub/switch.

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24
Q

Mesh network topology

A

interlinked computers/
devices, which use routing logic so data packets are sent from sending stations to receiving stations only by the shortest route.

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25
Hybrid network topology
network made up of a combination of other network topologies.
26
advantages of a bus network
- Even if one node fails, the remainder of the network continues to function. - It is easy to increase the size of the network by adding additional nodes
27
disadvantages of a bus network
- If the main cable fails, the whole network goes down. - The performance of the network deteriorates under heavy loading. - The network is not secure since each packet passes through every node.
28
advantages of a star network
- Data collisions are greatly reduced due to the topology. - It is a more secure network since security methods can be applied to the central node and packets only travel to nodes with the correct address. - It is easy to improve by simply installing an upgraded hub. - If one of the connections is broken it only affects one of the nodes
29
disadvantages of a star network
- The initial installation costs are high. - If the central hub/switch fails, then the whole network goes down
30
advantages of a mesh network
It is easy to identify where faults on the network have occurred. » Any broken links in the network do not affect the other nodes. » Good privacy and security, since packets travel along dedicated routes.
31
disadvantages of a mesh network
A large amount of cabling is needed, which is expensive and time consuming. » Set-up and maintenance is difficult and complex.
32
Cloud storage
method of data storage where data is stored on off-site servers.// Accessing a service/files/software on a remote server
33
Data redundancy
situation in which the same data is stored on several servers in case of maintenance or repair
34
Public Cloud
Computing services offered by 3rd party provider over the public Internet  Public is open/available to anyone with the appropriate equipment
35
Private Cloud
Computing services offered either over the Internet or a private internal network  Only available to select users not the general public
36
advantages and disadvantages of using cloud storage
Advantages: -Files can be accessed from any location using an internet connection. -No need for separate (high capacity) storage devices -Cloud storage can be free -Most cloud data services will have in-built backup Disadvantages: - Can only access (the cloud) with internet access -Security may not be strong -It can take a long time to upload/download the data
37
Twisted pair cable
type of cable in which two wires of a single circuit are twisted together. Several twisted pairs make up a single cable
38
Coaxial cable
cable made up of central copper core, insulation, copper mesh and outer insulation
39
Fibre optic cable
cable made up of glass fibre wires which use pulses of light (rather than electricity) to transmit data
40
Hub
hardware used to connect together a number of devices to form a LAN that directs incoming data packets to all devices on the network (LAN).
41
Switch
hardware used to connect together a number of devices to form a LAN that directs incoming data packets to a specific destination address only.
42
Router
device which enables data packets to be routed between different networks (for example, can join LANs to form a WAN)
43
modem
modulator demodulator. A device that converts digital data to analogue data (to be sent down a telephone wire); conversely it also converts analogue data to digital data (which a computer can process).
44
Gateway
device that connects LANs which use different protocols
45
Repeater
device used to boost a signal on both wired and wireless networks
46
NIC
network interface card. These cards allow devices to connect to a network/internet
47
ethernet
A protocol (suite)  For data transmission over standard / universal wired / cabled network connections  Uses Carrier Sense Multiple Access / Collision Detection (CSMA/CD)  Data is transmitted in frames  … each frame has a source and destination (IP/MAC) address  ... and error checking data (so damaged frames can be resent)
48
CSMA/CD
carrier sense multiple access with collision detection – a method used to detect collisions and resolve the issue
49
Bit streaming
contiguous sequence of digital bits sent over a network/internet
50
On demand (bit streaming)
system that allows users to stream video or music files from a central server as and when required without having to save the files on their own computer/ tablet/phone.
51
Real-time (bit streaming)
system in which an event is captured by camera (and microphone) connected to a computer and sent to a server where the data is encoded. The user can access the data ‘as it happens’ live
52
internet
massive network of networks, made up of computers and other electronic devices; uses TCP/IP communication protocols
53
World Wide Web (WWW)
collection of multimedia web pages stored on a website, which uses the internet to access information from servers and other computers.
54
public ip address
it is visible to any device on the internet
55
Private IP address
It is only visible to devices within the Local Area Network (LAN)
56
Dynamic IP address
A new one is reallocated each time a device connects to the internet
57
Static IP address
It does not change each time a device connects to the internet
58
HyperText Mark-up Language (HTML)
used to design web pages and to write http(s) protocols
59
Uniform resource locator (URL)
specifies location of a web page
60
web browser
software that connects to DNS to locate IP addresses; interprets web pages sent to a user’s computer so that documents and multimedia can be read or watched/listened to
61
Public switched telephone network
network used by traditional telephones when making calls or when sending faxes
62
tasks of a router
1- Receives packets from devices 2- Stores the IP and/or MAC address of all devices attached to it 3- find the destination of the packet * To assign / allocate private IP addresses to devices on LAN To receive packets from devices or the Internet * To forward / route packets to the destination * To find the destination of the packet * To assign / allocate private IP addresses to device on lan
63
wired vs wireless
Wired * Faster connection // higher bandwidth * …. needed as she is downloading/streaming large files * … less time waiting / less latency / fewer delays * More reliable / stable connection * … is less susceptible to issues with distance/walls/interference * More secure Wireless * Freedom of movement * … can move between different rooms with a mobile device and still receive/transmit data * … no need of a physical connection * Easily expanded if friends want to access the same network * Less cabling / expertise is needed * ... making the initial setup less expensive
64
using internet or www or both
using internet because sending data on the infrastructure * using WWW because accessing a website (that is stored on a web server operated by the webmail) that is part of the WWW
65
Describe the functions of a Wireless Network Interface Card
Provide interface to wireless network * … as an antenna * Receives analogue radio waves * … convert them to digital / binary * Checks incoming transmissions for correct MAC / IP address * … ignore transmissions not intended for it * Encrypts / encodes the data * Decrypts / decodes the data
66
Give one advantage and two disadvantages of transmitting data using satellites instead of copper cables.
not fixed to a single location * allows access in remote / rural areas 1 mark for each correct disadvantage (max 2): * high latency / lag / slow to connect * more expensive than wired methods, as need extra equipment * signal is affected by bad weather * the transmission speed is slower than fixed line broadband * direct line of sight needed
67
Give two benefits of dividing a network into subnetworks by subnetting the LAN.
improves security * reduces congestion * allows extension of the network
68
Describe how Carrier Sense Multiple Access /Collision Detection (CSMA/CD) is used in a bus network.
CSMA/CD is a protocol used to detect and prevent collisions in a bus topology * before transmitting, a device checks if the channel is busy * If the channel is busy the device waits // if the channel is free the data is sent * because there is more than one computer connected to the same transmission medium * ... two workstations can start to transmit at the same time, causing a collision
69
how does csma/cd works
when the frame of data s ready to be transmitted, the channel line is checked to see if its idle. if it is, the frame is sent and collision is checked. if collision signals are detected, jam signals are sent and transmission is stopped for a certain time interval and then the frame is sent again. this process is repeated until no collision is detected. When no collision is detected, the frame transmission is completed