1.3/1.4 Flashcards
what is compression?
the idea of trying to reduce the file size
what is the need of using compression
reducing number of bits in a file
making the storage capacity of the file lower
making data transfer of the file quicker
What is lossy compression?
Removing some of the data=reduce its size.
What is lossless compression?
Making the size of a file smaller without losing any of the information in the file.
advantages/disadvantages of lossy compression?
advantages = reduces file size , suitable for images,sound and videos
disadvantages = some of the data is lost and cannot be recovered , reduces quality of the image/sound ,
advantages and disadvantages of lossless compression?
advantages = none of the data is lost it is encoded differently , can be turned back into the original format , can be used on types of data ,
disadvantages = usually less effective = reducing the file size
what are the advantages of networking?
users can share files.
users can share peripherals: printers and connection to other networks e.g the internet.
users can access their files from any computer on the network
what are the characteristics of local area newtork (lan)
covers a small geographical area located on a single site.
all the hardware for a lan is owned by the organisation using it.
lan are wired with utp cable,fibre optic or wireless using Wi-Fi.
what are the characteristics of wide area network (wan)
covers a large geographical areas , connecting lan’s together.
infrastructure between the lans is leased from telecommunication companies who own and manage it.
wan’s are connected with telephone lines , fibre optics cables or satellite links
which hardware are needed for home solution
personal home devices for connecting to the internet tend to be multi-functions , all - in one devices acting as
switch
router
wireless access point
disadvantages of networking?
malware and viruses spread very easily between computers.
if a server fails the computers connected to it may not work.
the computer may run more slowly if there is a lot of data travelling on the network.
what is the client-server model?
where devices are reliant on services provided and managed by a central server;
what are the roles of client-server model?
manages access to the internet
provides email services
runs a backup of data
what are the advantages of client-server model?
- easier to manage security files
- easier to take backups of all shared data
- easier to install software updates to all computers
what are the disadvantages of client -server model?
- can be expensive to set up and maintain
- requires it specialists to maintain
- users will lose access if the server fails
what is the peer to peer model?
.
peer is a computer on a network and is equal to all other peers.
what is the role of the peer to peer model?
- peers serve their own files to each other
- each peer is responsible for its own security
-each peer is responsible for its own backup - peers usually have their own printers
- you can send print jobs to another peer to process but that peer would need to be switched on to be able to communicate with the connected printer
advantages of the peer to peer model?
- very easy to maintain
- cheaper to set up
- no expensive hardware to be required
disadvantages of the peer to peer model
- the network is less secure
- users will need to manage their own backups
- can be difficult to maintain a well ordered file store
what are the factors that affect the performance of a network?
bandwidth
the number of users
transmission media
the error rate
latency
what does network performance mean?
concerned with how well data is transmitted through the network
how does bandwidth affect the performance of the network?
measures how much data can be transferred over a network in a given time
how does the number of users affect the performance of the network?
the bandwidth of the network is shared between the users of a network
how does transmission media affect the performance of the network?
what the data is transmitted through.data can be carried around networks via cables or wirelessly
how does error rate affect the performance of the network
the number of errors that occur during data transmission
how does latency affect the performance of the network
measure of how much time it takes for a packet of data to travel across the network.
what is the hardware needed to connect stand-alone computers into a lan?
nic (network interface controller)
switch
wap
router
tranmission media: copper cables , fibre optic cables , radio waves
what does the nic do
enables the computer to be connected to a network.
what does the switch do
connects wired devices on a lan
what does the wap do
connects wireless devices on a lan
what does the router do?
connects different types of network together
what does the tranmission media do?
copper cable - transmits electrical signals (typically used in ethernet cables)
fibre optic cables - made up of thin glass strands (or fibres) which transmit data as pulses of light
radio wave - uses parts of em spectrum to connect devices wirelessly
what is the internet?
worldwide collection of computer networks
what is a dns
domain name system, it matches each domain name to its matching ip address
what is hosting
websites and others internet services needed to be placed on a web server.
what is the cloud?
storage, services and applications that are accessed via the internet
what the webserver?
this is a dedicated computer on the internet that responds to http and https requests by returning web pages requested by a client computer
what is a star topology?
all nodes are connected through a central point typically a switch or a hub.
what is a mesh topology?
all nodes are involved in the transmission of a message
node
device which is connected to a network
adv of star topology
fast - each node has its own connection to the centre.
reliable - if a fault occurs in one link other links are not neccessary affected
disadv of star topology
if the central switch/hub fails then the whole network goes down.