computer networks Flashcards

1
Q

kernel

A

tells you where to find operating system

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2
Q

network

A

2 or more devices(nodes) connected by some type of communications channel

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3
Q

node

A

any device connected to the network
-user device
-switch -connect nodes to each other
-router-connect to internet
-service device - printer or server

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4
Q

types of communication channel

A

bounded or unbounded(wireless)

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5
Q

server

A

computer designed to act as central network computer that provides various resources (network security, hardware access, disk space, printer access.

has software which manages logins and user access to computers on network

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6
Q

area eg school.office buildings network name (limited )

A

LAN , local area network

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7
Q

network name city

A

metropolitan area network (MAN)

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8
Q

network name large company

A

wide area network (WAN)

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9
Q

worldwide WAN

A

global area netwok

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10
Q

network individual eg hot spot

A

personal area network pan

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11
Q

network name home

A

home are network

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12
Q

router

A

small electronic device
joins networks together through wired or wireless connections

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13
Q

types of networks

A

LAN,MAN,WAN,GAN,PAN,HAN

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14
Q

cloud computing

A

makes use of computing services like storage,databases,software,networking and over the internet “the cloud”

only pay for services you use

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15
Q

cloud competing

A

making use of competing services like storage, databases, software, networking + more over internet “the cloud”

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16
Q

types of nodes

A

devices that users use (laptop,desktop,mobile device)
devices to connect nodes to each other (switch)
device to connect to internet (router)
device to provide service (server or printer)

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17
Q

switch

A

connect nodes in network using communication media such as cables.
node connected to ports in switch

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18
Q

3 parts of communication media

A
  1. hardware - source or sender
  2. hardware- destination or receiver
  3. connection between source + destination
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19
Q

what is the connection between source and destination

A

communication channel or transmission medium

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20
Q

bandwidth

A

maximum amount of data that it can transfer per unit time (usually bits/sec)

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21
Q

what is the rate that data is transferred over communication channel measured in

A

thousands of bits per second (kilobits per second Kbps)
millions of bits per second (megabits per second Mbps)
billions of bits per second (gigabits per second Kbps)

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22
Q

what is bounded media

A

consist of physical cabling
commonly used for wired LANs

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23
Q

UTP

A

unshielded twisted pair
most common bounded media cabling in small LANs
several pairs of twisted pairs in an outer protective plastic cover
has RJ45 connector on each end (one end to port on device, one end on switch)

24
Q

why are wires twisted

A

eliminate interference from signals on other wires and from other electrical devices

25
Q

attenuation

A

signal loses strength over distance

26
Q

electro-magnetic interference

A

signals from other sources (eg machinery) corrupt signals travelling in copper cables near by

27
Q

eavesdropping

A

signals travelling along copper cables intercepted by outsiders

28
Q

crosstalk

A

signals in adjacent wires interfere with each other

29
Q

advantages of utp

A

inexpensive and easy to install
supports fast transmission rates
widely used and tested
can be used in many diff networks

30
Q

disadvantages of UTP

A

susceptible to interference
crosstalk - signals
attenuation -distance limitations (repeater used to join 2 long lengths of cables- amplify signal on cable)

31
Q

STP

A

shielded twisted pair
more expensive, bulkier
twisted pairs open enclosed in protective foil
less affected than UTP by interference

32
Q

fibre optic cable

A

central glass/plastic core surrounded by several layers of protective materials.
cladding used to surround core + reflect light back into core
transmits light pulses rather than electronic signals—eliminating interference

33
Q

connector of fibre optic cable

A

SC connector

34
Q

advantages of fibre optic cable

A

supports much faster transmission rates - light travels faster than electronic signals
more secure than UTP- light signals cannot easily be tapped
can transmit longer distances than UTP —light signals dont weaken like electronic signals in copper wires
light signals not susceptible to interference unlike electronic signals
light signals immune to lightning + electrical surges

35
Q

how is fibre optic cabling used as a backbone

A

used to join LAN segments in diff buildings together - not affected by lightning

36
Q

unbounded media

A

no cables, carry signals
use air to transmit radio signals such as bluetooth, infrared beams, microwaves, satellites, laser light signals

37
Q

how do wireless signals remain separate

A

each type of signal uses diff frequency ( Hertz or cycles/sec)

38
Q

microwave transmissions

A

long distance
affected by weather conditions

39
Q

main types of microwave transmissions

A

terrestrial
satellite

40
Q

terrestrial microwaves

A

land based
use line of sight method for transmitting data between 2 anntea
can transmit over 50 km (no obstacle)

41
Q

problem w/ copper cables

A

attenuation
electro magnetic interference
cross talk
eavesdropping

42
Q

disadvantages of fibre optic cables

A

expensive to purchase and install
strict complex installation criteria

43
Q

satellite transmissions

A

transponders receives signals
converts to different frequency
boosts signal
sends to stations on ground

44
Q

types of satellites

A

geo stationary- fixed position above earth’s surface and rotate at same speed as earth
good for TV broadcasting
low orbit-nearer to earths surface,rotate every few hours
better for interactive communication

45
Q

radio wave transmissions

A

short distance
can travel through walls and buildings
can travel long or short depending on frequency
radio,TV.phones - WiFi,bluetooth

46
Q

router in the home

A

connects all nodes in network to other networks outside the home

47
Q

how to get fibre into your home

A

fibre optic backbone cable connected from local distribution node to your street
fibre connected from distribution box into your home
Optical Network Terminal (ONT) connects fibre to router

48
Q

firewall

A

system designed to prevent unauthorised access to/from private network

49
Q

types of servers

A

file server-store files to be accessed by network users
print server- printers to be shared by computers on network
web server+accepts requests for web pages and sends to client machines
email server-stores mail and distributes to users
proxy server- all web content passes through- disallows access to unauthorised users

50
Q

local vs cloud servers

A

local-servers located in organisation -company has physical control over set up , no need for internet to access BUT have to pay for setting up and managing

cloud- no expensive of continual upgrading. storage can be added,pay for what you use,backed up often BUT no access if no internet connection

51
Q

NAC

A

network area control
can only access network if user login complies w/protocols
must authenticate by verifying login information

52
Q

advantages of computer networks

A

communication
file sharing
printer and resource sharing
centralisation
data transfer
productivity

53
Q

disadvantages of computer networks

A

security issues
spread of computer viruses
cost
dependancy on central servers

54
Q

data transfer rate

A

amount of data that can be transferred between 2 points on a network in a given time

55
Q

problems w copper wires

A

attenuation
electro-magnetic interference
eavesdropping
cross talk