1.3 – Computer networks, connections and protocols Flashcards

1
Q

What is a network

A

two or more devices that are connected so that they can communicate with each
other.

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2
Q

Stand-alone device

A

A device that is not connected to any other device and ‘stands’ on its own

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3
Q

Advantages of networks

A

-files can be shared
-peripherals can be shared
-an internet connection can be shared
-users can access files and data from any device on the network
-users can communicate with each other over the network
-Software updates can be rolled out all in one go across all the devices on the network,
saving time

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4
Q

Disadvantages of networks

A

There is an increased security risk to data. Devices are
easier to hack when connected on a network
Malware and viruses can spread easily and quickly between
devices on the network if appropriate security measures are not put in
place
If the server for the network fails, the whole network may go down
If there is a large amount of data travelling over the network, the
devices on the network may slow down
Networks can be expensive to install and maintain e.g. the
buying and installation of the hardware, and hiring someone
to monitor the network can be expensive

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5
Q

What is a LAN

A

-local area network
-A LAN is a network that covers a small geographical area, such as one building or two
buildings close together

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6
Q

examples of LAN

A

A school
A house
A corner shop

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7
Q

what is a WAN

A

-wide area network
-A WAN is a network that covers a large geographical area, such as a city, country, or the
world. They are a series of LANs all connected

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8
Q

examples of WAN

A

The internet
An international bank
ATMs (Automated Teller Machines) that dispense money

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9
Q

How does bandwidth affect the performance of a network

A

-the amount of data that can be sent and received successfully in a given time
-more bandwidth means more data having to be sent so slower network speed

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10
Q

How does the number of users affect the performance of a network

A

Too
many users on the network will mean more of the bandwidth is being spread out to try and
meet all the users’ needs. When there is not enough bandwidth to manage all the users on the
network, the network will slow down.

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11
Q

How does transmission media affect the performance of a network

A

A
wired network for example has a higher bandwidth compared to a wireless network, due to
less interference. Using fibre optic cabling rather than copper cabling will have a higher
bandwidth, due to less interference again.

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12
Q

How does error rate affect the performance of a network

A

This refers to the number of errors that occur when data is transferred. The higher the error
rate, the more frequently data has to be resent before arriving safely and correctly.

for example:
if the user is far from the WAP
if the type of media is wireless

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13
Q

How does latency affect the performance of a network

A

This is the delay from transmitting data to receiving it. This can be increased by not having
the correct network hardware to direct traffic around the network appropriately, causing
‘traffic jams’ and therefore slowing data down.

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14
Q

What is a client-server network

A

the client makes a service
request to the server. The server then sends the
requested information to the client

There is a central dedicated server (or group of central dedicated servers in larger
businesses), and all clients request information from them.

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15
Q

What is a peer-to-peer network

A

In this model there is no central dedicated server. Instead, all the devices on the network
take on the responsibility of being a server, storing files and
handling service requests. Each device has an equal
responsibility for providing data when requested

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16
Q

security,management ,dependency,performance,backups of client-server networks

A

sec-controlled by server and is consistent throughout each device
mana-server manages the network but needs specialised network engineers to maintain.
depend-all dependent on server,if goes down,whole thing goes down
perform-can be upgraded to improve and maintain performance,but is expensive
backups-data is backed up on the server incase of a data breach

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17
Q

security,management ,dependency,performance,backups of p2p networks

A

sec-all clients are responsible for sec of network and themselves,may not be consistent
management-anyone can set up and be responsible for it as no central managing
depend-if one goes down,others still up as not dependent to one central server
perform-if one is slow others are slow ,but upgrading is cheaper than client server
backups-must be done individually.This can lead todata being lost not backed up, or media containing the backups being lost

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18
Q

What hardware is required to make a LAN

A

These pieces of hardware are the:

NIC (Network Interface Controller/Card),
Wireless Access Point,
Switch,
Router,
Cabling.

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19
Q

NIC(network interface card)

A

connects a device to a wired or wireless
network and is built into the device. It uses protocols to ensure the
communication between the device and network is consistent.

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20
Q

WAP(Wireless access point)

A

allows devices to connect to a network
wirelessly, without the need of any cables.

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21
Q

switch

A

sends data around a network. A switch however sends
data only to the correct device on the network, rather than all the devices
on the network. This is because they can read the data packets being sent
and therefore work out where the receiver is.

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22
Q

Hub

A

used to also send data around a network. A hub however sends
data to all devices on a network, rather than just the correct device. This
is therefore not good for security, as it allows any device on the network
to intercept a data packet and potentially steal its contents.

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23
Q

router

A

sends data between multiple networks. You cannot
connect to a WAN such as the internet without a router. A router often
has a modem built into it now, which enables you to connect to the
internet. A router uses an IP Address to direct traffic between
networks.

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24
Q

What is an IP address

A

-IP Addresses are used to
allow data to be directed around the internet from senders to the correct receivers.
-An IP Address is unique to each device connected to the internet

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25
Q

cabling

A

used to create a wired connection in the network

two types:
copper cables
fibre optics

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26
Q

Copper Cables (Unshielded Twisted Pair)

A

used to create a wired network. Copper cables are twisted around each
other, where one cable is responsible for sending data, and one is
responsible for receiving data. Copper Cables can also be known as
Ethernet Cables.

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27
Q

Fibre Optic Cables

A

Use light to transmit data. They can cover a
much large range compared to Copper Cables and have a much higher
bandwidth due to less interference. Fibre Optical cabling still remains
expensive and is therefore still emerging. However, it is now starting
to be more widely used.

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28
Q

Wired or wireless -bandwifth

A

wired-less interference so more likely to have a higher bandwidth.Means a wired network will be able to cope with more traffic and more users compared to a wireless netowrk

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29
Q

range wired or wireless

A

wireless-with wired u are restricted to the locations where you can access an ethernet cable.With wireless you can access anywhere as long as you are in range of a wireless access point

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30
Q

security-wired or wireless

A

Wired-If someone wants to hack into your network and you have a
wired network, they have to physically plug an ethernet cable
into their device. This means it is much more difficult to secretly
hack a wired network. This is compared to a wireless network
where, as long as the user is in range of the Wireless Access
Point, they can attempt to hack the network.

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31
Q

cost wireless or wired

A

wireless-It is cheaper to set up a wireless network, as you only need to
purchase the Wireless Access Point and other necessary
hardware. This is compared to a wired network where you
would need to buy all the necessary hardware, as well as run
cabling all through the building. This would cost for both the
cabling and the installation damage, as well as the cost for the
specialist team to come and fit the cabling

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32
Q

what is the internet

A

a collection of LANs all connected. It allows data to be transferred from one
LAN to another. The internet is the physical part of the WAN, containing all the hardware
required to share data across a large area.

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33
Q

what is the World Wide Web

A

a service used on the internet, to allow users to interact with
the internet. It allows users to share data and files across the internet in a user-friendly way.

34
Q

What must a user be connected to to access the internet

A

internet service provider-like SKY,VIRGIN AND BT

35
Q

What is a DNS (Domain name servers)

A

special servers on the internet. Their job is to convert URLs
the user types in into IP Addresses, so the locations of web pages associated with a website
can be found.

36
Q

how a DNS works

A

When we search for a website using a URL, the DNS searches a
database to find the IP Address for the website, which then directs us to the correct server
containing all the information for that website. If the first DNS does not have the required
information, it will pass us on to another DNS, which will check, and so on.

37
Q

Hosting

A

Hosting is when websites are stored on dedicated servers In order for a website to be available on the internet for users to access.

. Hosts often provide 24/7 access to
the website, access for multiple users, and greater security, compared to hosting your own
website. However, should the host server go down, your website will go down also. This could
lose you money or customers, so there are both advantages and disadvantages to paying a
company to host your website.

38
Q

web servers and clients

A

Data for websites is stored on a web server. These are special, dedicated servers responsible
for managing requests from clients and sending data so websites can be viewed and accessed.
A client is a device that is requesting this data. When loading up a website the client will send
a request to the web server for the relevant websites data; the web server will process this
request (here a process called packet switching takes place) and then send the requested data
to the client.

39
Q

The cloud

A

Cloud Computing is when your applications and data are stored and accessed via the internet,
rather than locally (on your device).

40
Q

advantages to the cloud

A

✓ Data is often backed up in a different location to where your
network is, therefore protected should you ever need to
restore it due to loss or theft
✓ There is often cross compatibility, meaning applications and files can be
accessed on different devices (e.g. phones, tablets, laptops etc.)
✓ Updates for applications are done automatically, meaning you always
have the most up to date version of the application
✓ Online applications are often free, saving the cost of
buying licenses for the application
✓ People can work on the go, and on multiple devices, as
long as they have an internet connection

41
Q

disadvantages to the cloud

A

-When something is uploaded to the cloud, you can
sometimes lose ownership to it, which can lead to Copyright
issues
❖ You are usually limited to a small amount of storage space
for free, before having to pay for further storage
❖ The applications provided may not always offer you all the features you
want or need, compared to the bought versions
❖ Data is easier to hack when stored online. Despite companies who offer
cloud services providing security measures, it is not possible to
guarantee data security
❖ Users must always have an internet connection in order to
access applications and files. Therefore, if your internet
connection drops, you would not be able to access your files
or applications

42
Q

what is a topology

A

the arrangement of nodes and connections in a computing network

43
Q

star topologies

A

all devices are connected together via a central switch/hub. Each device is
connected via its own cable to the switch/hub, and therefore is independent to other devices
on the network.

44
Q

ADV AND DISADV to star topologies

A

The advantages to the star topology are:
✓ Limited data collisions due to the switch/hub managing data flow, reducing the error
rate of the network
✓ Easy to add additional devices to, and also to add additional switches/hubs to, which
allows you to expand the network
✓ If one device on the network fails, the network can still continue to work
The disadvantages to the star topology are:
❖ Additional cost due to needing to purchase a switch/hub
❖ If the switch/hub fails, then the network will fail

45
Q

Mesh topology

A

all devices are connected to as many other devices as possible. This
creates multiple connections between devices.
In a mesh topology, data flows in multiple directions around the network. As there are
multiple connections, data can flow via the quickest route if there is a build-up of traffic on the
network

46
Q

ADV AND DISADV to mesh topologies

A

✓ If one connection fails, the network can still continue to work. Data will simply just be
routed via a different connection in order to reach its destination
✓ Data transfer can be quick. This is due to having multiple connections. If data traffic
builds up in one area of the network, then alternative routes can be used to ease
congestion and reduce latency

The disadvantages to the mesh topology are:
❖ Increased cost due to the amount of cabling and switches required

47
Q

What is Wi-fi

A

a common standard used for wireless networks. It is often what we refer to when
connecting to a wireless network

48
Q

what is used in order for data to be sent via wi-fi

A

frequencies and channels

49
Q

what are frequencies and channels

A

Frequencies are used to transmit signals. 2.417GHz is an example of a frequency. In order to
make the frequency more convenient to remember and use, it is given a channel number.The channel is set by the NIC

50
Q

what must be the same for the devices to connect via WI-Fi

A

channels-if
your router is set to channel 2, but your computer is set to channel 3, the devices will not be
able to connect to each other

51
Q

how can channel interference affect the network

A

If other devices are set to the
same channel, they can interfere with the signals being sent between your device and the
router. This can then slow your connection down.
However, if data is being sent wirelessly, it is easier to intercept and steal. Data therefore
must be encrypted, in order to protect it whilst being transmitted.

52
Q

encryption

A

scrambling data before being transmitted, into a secret code. In order to
decrypt the code, you must have a ‘master’ key. Only the device sending and the device
receiving the data has this key. This is because prior to the data being a sent, a ‘handshake
protocol’ is used to ensure the same correct and valid key is being used by both the sender
and receiver.

53
Q

What is Ethernet?

A

Ethernet is a standard for networking technologies used for communication on a wired LAN (Local Area Network).

54
Q

What type of cables are commonly used for creating Ethernet connections?

A

Twisted Pair Cables are commonly used for creating Ethernet connections.

55
Q

Why are Twisted Pair Cables preferred for Ethernet connections?

A

Twisted Pair Cables allow data to be both sent and received simultaneously, as different wires are used for each, eliminating the need for a special protocol called CSMA/CD.

56
Q

What was the purpose of CSMA/CD in wired networks?

A

CSMA/CD (Carrier Sense Multiple Access/Collision Detection) was used to detect when data was being transmitted over a wired network. It helped avoid transmitting data at the same time to prevent data collisions.

57
Q

Why is CSMA/CD no longer necessary with Twisted Pair Cables?

A

Twisted Pair Cables have separate cables for sending and receiving, eliminating the need for CSMA/CD as they inherently prevent data collisions.

58
Q

How is data transmitted via an Ethernet connection?

A

Data is transmitted in frames, which include bits for synchronizing transmission and receiver clocks, a start frame delimiter to signify the start of the data packet, sender and receiver MAC Addresses, actual data, and a cyclic redundancy check for error checking on the frame.

59
Q

What is required for data to be transmitted over and between networks?

A

For data to be transmitted over and between networks, both IP Addresses and MAC Addresses are required.

60
Q

What is the uniqueness of an IP (Internet Protocol) Address?

A

An IP Address is unique to each device connected to the internet. It is used to direct data around the internet from senders to the correct receivers.

61
Q

What is the role of IP Addresses in networking?

A

IP Addresses play a crucial role in networking by allowing data to be directed to the correct receivers on the internet.

62
Q

What is a MAC (Media Access Control) Address specific to?

A

A MAC Address is specific to a piece of hardware on a network. It is built into the hardware (NIC) and cannot be changed.

63
Q

What distinguishes an IP Address from a MAC Address in terms of their functions?

A

While an IP Address is used for routing data over the internet, a MAC Address is specific to a piece of hardware on a network and is associated with the NIC (Network Interface Card).

64
Q

What are the two types of configurations for IP Addresses?

A

IP Addresses can be either static or dynamic.

65
Q

Provide an example of when an IP Address might remain static.

A

An example of a static IP Address is that of a web server, as it does not change.

66
Q

How does IMAP differ from POP in handling emails?Can MAC Addresses be changed?

A

No, MAC Addresses, fixed into the NIC (Network Interface Controller/Card) of each device, cannot be changed.

67
Q

Why are network protocols necessary for devices to communicate over a network?

A

Network protocols are necessary because they establish rules or standards that devices must follow when communicating over a network. Without protocols, communication on a network would not be possible.

68
Q

What is TCP/IP, and what role does it play in networking?

A

TCP/IP (Transmission Control Protocol/Internet Protocol) is a network protocol that sets out rules for devices to follow when communicating over a network. It plays a crucial role in packet switching (TCP) and the routing of packets on a Wide Area Network (IP).

69
Q

What is the purpose of HTTP in networking?

A

HTTP (Hyper Text Transfer Protocol) is used to transfer web pages from web servers to clients.

70
Q

How does HTTPS differ from HTTP?

A

HTTPS (Hyper Text Transfer Protocol Secure) is a more secure version of HTTP. Data sent using this protocol is encrypted, making it more secure. It is typically used for transferring secure web pages, such as when users log into their online banking accounts.

71
Q

What is the role of FTP in networking?

A

FTP (File Transfer Protocol) is used to transfer large files over a network and to organize files for websites on a web server.

72
Q

Explain the purpose of POP (Post Office Protocol) in networking.

A

POP is used to access emails from an email server for the client to read. The email is downloaded onto the user’s current device and is removed from the web server when accessed.

73
Q

How does IMAP differ from POP in handling emails?

A

iMAP (Internet Message Access Protocol) is used to access emails from an email server for the client to read. Unlike POP, IMAP allows the user to access the email directly from the email server, eliminating the need to download or remove it. It is considered more advanced than POP.

74
Q

What is the function of SMTP in networking?

A

SMTP (Simple Mail Transfer Protocol) is used to send emails to an email server.

75
Q

What is layers

A

dividing the complex process of transferring data between devices into manageable sub-problems

76
Q

Application layer

A

This layer makes sure the data being produced and sent is in a format the application being used
can understand

77
Q

Transport layer

A

This layer establishes a connection with the network, and agrees protocols, size of packets, speed
of transfer etc. with the receiving device

78
Q

Network layer

A

This layer transmits data across the network. It identifies the destination IP address and the
quickest route

79
Q

link layer

A

This layer connects/links to devices on the network. It also decides whose turn it is to communicate,
and converts all data into digital signals for sending
adds MAC addresses for the actual physical connection between nodes.

80
Q

order of layers:

A

application-transport-netowrk-link

when back:

link-network-transport-application