Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Computer science A level > Networks and the internet > Flashcards

Networks and the internet Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

what is a network topology

A

the way a network and its connected devices are connected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what does CSMA/CA stand for

A

Carrier Sense Multiple Access with collision avoidance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what does data travel over when we use wifi

A
  • a frequency (channel)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

implications of using wireless networks

A
  • as communication is done in an open space, it’s less secure
  • transmission speed is lower because of traffic
  • has a limited amount of bandwidth for communication and breaches of network security
  • can be easily hacked
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

channels have a frequency range of….

A

22MHZ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

describe the CSMA/CA without RTS/CTS

A
  • if a device is ready to send some data, it starts and assembles the packet of data it wants to send
  • asks if the channel idle
  • if yes, data is transmitted
  • if no, device waits a random amount of time and checks if the channel is idle again
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

describe the CSMA/CA with RTS CTS

A
  • transmitting device checks for traffic
  • if another transmission is in progress, the transmitter continues to wait
  • if channel is idle, transmitter would send a request to send
  • Receiver/WAP responds with a clear to send signal
  • if CTS not received, transmitter would wait a random amount of time before sending the RTS
  • when CTS is received, the transmitter begins transmitting data
  • receiver sends acknowledgment if all data is received
  • if no acknowledgment is sent, data is resent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

the hidden node problem and how to fix it

A
  • node a can see the WAP because it’s in range, node b can also see WAP
  • node a cant see node b because they are out of range with each other
  • if both nodes try to transmit data wirelessly, using CSMA/CA without RTS will result in data collisions
  • by adding an RTS/CTS, node A doesn’t need to make any assumptions abt how many nodes there are etc, it just adds an extra layer of protection, and the WAP checks everything
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the Wireless AccessPoint

A
  • a hardware device that allows wireless devices to connect to a wired network using Wi-Fi or related standards.
  • it bridges wireless and wired networks,
  • enhance network connectivity by increasing the range and coverage area of the network
  • provide flexibility in network setup and expansion, allowing for easy addition of new devices
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is a wireless router

A

a networking device that forwards data packets between computer networks, eg over the internet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is a wireless network adapter/interface

A
  • a hardware device that enables a computer or other device to connect to a wireless network
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what does a WirelesssAccessPoint require access to

A

it requires a connection to the router, and the router requires a connection to a modem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is a modem

A

a modulator demodulator - a computer hardware which converts data from a digital format into a format suitable for an analog transmission medium such as a telephone or radio (a DAC)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

features of service set IDentifiers (SSIDs)

A
  • identifies each network by a unique name
  • must be used by all devices on that network
  • can be set manually or automatically
  • can be hidden to make it harder to detect
  • can be set to broadcast a range of wireless devices in range of an access point
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what do WPA and WPA2 do

A
  • WPA and WPA2 utilize a form of authentication known as PSK
  • Users must enter a password to authenticate themselves to the network.
  • WPA and WPA2 dynamically generate and manage encryption keys to enhance security. these keys are periodically changed
  • they use MAC (Media Access Control) address filtering, which allows or denies network access based on the unique hardware address of a device.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is serial data transmission

A

a type of data transmission where bits are sent via an interface one at a time over a single wire from the source to the destination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is parallel data transmission

A

where multiple bits are sent simultaneously over a number of parallel wires

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

disadvantages of parallel data transmission

A

each individual wire has different properties, there is a possibility that bits can travel at different speeds over each wires, creating the problem of skew

  • parallel transmission only works over short distances
  • parallel transmission can suffer from crosstalk and timing issues since each bit travels on a different wire, potentially interfering with one another and reducing overall efficiency
19
Q

advantages of serial transmission over parallel

A
  • large reduction in size and complexity of connectors in serial transmission leads to lower costs
  • crosstalk will not occur, as all bits are sent on the same wire, reducing interference and allowing for longer distances., may result in corrupted words
  • Serial transmission is cheaper; due to needing fewer wires / less complex hardware;
  • skew wont occur as bits are sent one at a time
  • serial links are more reliable over longer distances than parallel
  • signal frequency can be much higher with serial because of the lack of interference at higher frequencies, resulting in a higher net data tranfer rate, even though less data is transmitted per cycle
20
Q

what is bit rate

A

the number of bits that can be sent in a given unit of time

21
Q

what is baud rate

A

the number of signal changes in a given period of time/in a second

22
Q

baseband mode

A

in baseband mode, only two voltages are used

23
Q

bit rate equation

A

bit rate of channel = baud rate x n of bits per signal

24
Q

what is bandwith

A
  • The range of frequencies that can be transmitted across a network connection;
  • shared between all active users, so too many users can cause performance to decrease
25
Q

what is latency

A
  • the time delay of data to travel from source to destination
26
Q

what is synchronous transmission

A

when receiver and transmitter are synchronised by a common clock

27
Q

advantages of synchronous transmission

A

timing using a clock signal allows for a constant and reliable transmission for time sensitive data
- The synchronization between sender and receiver ensures that data arrives in a steady, predictable flow
- Synchronous transmission can handle larger volumes of data at higher speeds because it doesn’t need to include start and stop bits for each byte, reducing overhead.

28
Q

examples of time sensitive data

A

real time video or voice

29
Q

what is asynchronous transmission

A
  • transmission of data where receiver and transmitter not synchronised by a clock
    -one byte is sent at a time, with each character being preceded by a start bit and followed by a stop bit
30
Q

examples of things that use synchronous transmission

A

CPU - the clock emits a signal at regular intervals and transmissions along the address, data and control bus start on a clock signal, which is shared by both receiver and sender

31
Q

Purpose of the start and stop bit

A
  • The start bit alerts and synchronizes the receiver to the start of a data packet
  • The stop bit ensures clear separation between data packets, giving the receiver time to reset and get ready for the next packet.
32
Q

what are protocol

A

a set of rules which govern communication

33
Q

advantages of disabling SSIDs

A

prevents the network from appearing in the list of available networks, making it less visible to potential attackers

34
Q

advantages of mac addressing

A

mac address whitelisting means only approved devices can join he network

35
Q

what are SSIDs

A

they identify the network

36
Q

things that affect network performance

A

topology
- bandwidth, higher bandwidth increases performance
- choice of hardware
- wired or wireless, wired are ussually faster and more reliable

37
Q

what is a wide area network

A

a collection of computers connected over a large geographical area, like the internet

38
Q

advantages and disadvantages of asynchronous transmission

A
  • Easier and cheaper to implement because it doesn’t require synchronization between the sender and receiver.
  • Ideal for low-speed communication and can handle irregular data transmission rates

DISADVANTAGES:
- Additional start and stop bits increase the amount of data transmitted, reducing efficiency.
- Generally slower due to the need to process each byte individually and add control bits.

39
Q

advantages and disadvantages of synchronous transmission

A
  • No start and stop bits, so it is more efficient for transmitting large amounts of data
  • Typically faster because data is sent in a continuous stream.

DISADVANTAGES -
- Requires synchronization between the sender and receiver, making it more complex and expensive to implement
- Initial setup and synchronization can take time, making it less suitable for small amounts of data or sporadic transmissions

40
Q

relationship between bit rate and bandwidth

A

directly proportional

41
Q

what is WIFI

A
  • A wireless local area network that is based on international standards.
  • Used to enable devices to connect to a network wirelessly
42
Q

advantages of SSIDS

A
  • ## Using unique SSIDs reduces the likelihood of connecting to the wrong network accidentally and helps prevent unauthorized access
43
Q

why is protocol important

A

to ensure that equipment from different suppliers can communicate

44
Q

items that are covered by communication protocol

A

Physical connections, cabling, mode of transmission, speed, data format, error correction.

Computer science A level (29 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions