Networks amd the internet Flashcards

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1
Q

what is a local area network

A

a network which consists of a number of computing devices on a single site or in a single businesses

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2
Q

what is a bus topology

A

where all computers are connected to a single cable. the ends of the cable are plugged into a terminator

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3
Q

advantages of bus topologies

A

cheaper to install as it requires less cable than a star topology and does not require any additional hardware

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4
Q

disadvantages of bus topology

A
  • if main cable fails, network data can’t be transmitted to any of the nodes
  • performance degrades with heavy traffic
  • low security as all computers in the network can see all data transmissions
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5
Q

what is a physical star topology

A

one that has a central node, which may be a switch or computer, which acts as a router to transmit messages

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6
Q

advantages of a star topology

A
  • if one cable fails, only one station is affected, so it’s easier to isolate faults
  • consistent performance even when network is being heavily used
  • higher transmission speeds give better performance than a bus network
  • no problems with collisions as each station has its own cable to the server
  • system is more secure as messages are sent directly to the central computer and cannot be intercepted by other stations
  • easy to add new stations without disrupting the network
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7
Q

disadvantages of a star topology/network

A
  • may be costly to install because of the length of cable required
  • if the central device goes down, network data can no longer be transmitted to any of the nodes
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8
Q

what is the node connected to on a star topology

A

a central device , typically a switch

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9
Q

what does a switch do

A

it keeps a record of the unique MAC address of each device on the network and can identify which particular computer on the network it should send the data to

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10
Q

difference between physical and logical topology

A
  • the physical topology of a network is its actual design layout
  • the logical topology is the shape of the path the data travels in, and describes how components communicate across the physical topology
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11
Q

how can we make a star topology act like a bus one

A
  • use a bus protocol
  • Use a central device that acts as a simple hub instead of a switch
  • Ensure that all devices connected to the hub share the same communication medium
  • Implement a collision detection and handling mechanism, such as (CSMA/CD), to manage simultaneous data transmissions and collisions,
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12
Q

operation of a physical bus network

A
  • data cannot be simultaneously transmitted in both directions (duplex transmission not possible)
  • each station receives all network traffic
  • the traffic generated by each station has equal transmission priority
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13
Q

what is an MAC address

A

an address which is assigned into a card and uniquely identifies a device
- 48 bits long and is written as 13 hex digits

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14
Q

used of mac addresses

A

tracking people

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15
Q

what is a client server network

A
  • computer networks that use a dedicated computer (server) to store data, manage/provide resources and control user access.
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16
Q

advantages of a client-server network

A
  • security is better since all files are stored in a central location and access rights are managed by the server
  • backups are done centrally so there is no need for individual users to back up their data
  • if there is a breakdown and some data is lost, recovery procedures will enable it to be restored
  • data and other resources can be shared
  • servers will be accessible at all times
17
Q

disadvantages of client-server network

A
  • expensive to install and manage
  • professional IT staff are needed to maintain the servers and run the network
18
Q

what is peer to peer network

A
  • there is no central server
  • individual computers are connected to each other, either locally or over a wide area network so that they can share files
  • each computer has equal status
19
Q

advantages of peer to peer

A
  • cheap and easy to set up
  • enables users to share resources such as a printer or router
  • no centralised server, if one peer fails, others can still use the network
20
Q

examples of when peer to peer is used

A

video on demand- hundreds of computers can be used to hold part of the video and share the load
- file transfer
- wireless printing
- bluetooth speakers

21
Q

disadvantages of peer to peer

A

piracy
- no central management, updates for the software are harder
- file duplication
- peers may lose connection easily

22
Q

why is peer networking used for piracy

A

because it’s impossible to trace the files which are being illegally downloaded

23
Q

consequences of piracy

A
  • the more movies that stolen and illegally downloaded, the fewer resources movie makers have to invest in new films
24
Q

what is wifi

A

a local area wireless technology that enables you to connect a device to a network resources or to the internet via a WAP

25
Q

how to connected to a wireless network

A
  • a computer needs a wireless network adaptor
  • all stations share a single radio frequency communication channel
  • each station is constantly turned in on the frequency to pick up transmissions
  • transmissions are received by all the stations within range of the WAP
  • to connect to the internet , the WAP usually connects to a router
26
Q

what is a station

A

the combination of computer and interface controller

27
Q

why is serial transmission favoured over long distances

A
  • eliminates the risk of desynchronisation
  • bits are transmitted simultaneously and may arive at different times
28
Q

what is a network

A

a collection of connected computers

29
Q

describe the logical operation of a bus topology

A

A node broadcasts data (to the entire network);
All/Any nodes on the network receive/read the data;
A node examines the received data to check if it is the intended recipient;
Only one node can (successfully) transmit data at a time // Nodes use a shared
transmission medium

30
Q

how can bit rate be higher than baud

A

Bit rate can be higher than baud rate if more than one bit is encoded in each signal
change;

31
Q

Explain the operation of a physical star topology

A

Every device is (directly) connected to a central node/switch/hub;
Every device sends data via the central node/switch/hub;
The switch sends packets of data to the intended recipient only