computer networks Flashcards
what is a computer network?
a collection of computers linked together to facilitate communication and the sharing of resources, either by wires or wirelessly
what are some advantages and disadvantages of computer networks?
advantages
computers can share resources such as printers
files can be accessed through any computer in the network
data is easily backed up as it is stored centrally in the server
easy to install and update software
easy and cheap to communicate ( email )
disadvantages
purchasing network hardware is expensive
managing a large network is complicated
viruses may be able to infiltrate the network and infect every computer
some networks are dependent on servers, so if the servers go down then there can be disruption
what are some advantages and disadvantages of wired networks?
advantages ( wired )
easy to connect new devices
no need to lay cables
devices can be portable if they are within range of the access point
disadvantages
connection speeds reduce the further from the access point you are
can be less reliable and less secure
if many devices try to use the network, connection can be very slow
what are some advantages and disadvantages of copper wires?
a cabled telephone can be powered directly from the copper cable, so the phone will still work if there is a loss of power - cheaper
what are some advantages of fibre wires?
can provide higher bandwidth - transmit data over long distances - do not break as easily as copper - expensive :(
what are the advantages and disadvantages of a star topology?
advantages
faster data transfer as each wire isn’t shared with other computers
if one cable fails the other workstations are not affected
consistent performance even when the network is heavily used
disadvantages
can be costly to install because there is a lot of cabling and extra hardware such as the switch
it the server or the central switch fails then the whole network goes down
what are the advantages and disadvantages of a bus topology?
advantages
less cable so easy and inexpensive
no reliance on a central node
easier to add more devices as they only need to connect through central cable
disadvantages
if the main cable fails then the whole network goes down
cable failures are hard to isolate because all fo the computers in the network are affected
low security as every node can see all the transmissions
performance slows down as the amount of traffic increases
what is a LAN?
a group of connect devices that share information, usually over a single room or small geographical area
- businesses, schools and universities
what is a PAN?
connect devices over a very short range, usually centred around a single user, like wireless headphones
what is a WAN?
a wan connects lans that are in different geographical areas
- the internet, business with offices in different countries
what are the layers of TCP/IP model?
application layer
transport layer
internet layer
link layer
why are layers important?
- they break the network down into manageable chunks, which helps developers concentrate on only one area of the network without having to worry about the others
- layers are self-contained, they can be changed without the other layer being affected
- having set rules for each layer forces companies to make compatible, universal hardware and software
differences between TCP and UDP?
they are both transport layer protocols which control the packaging and unpacking of data
but TCP establishes a connection between the sending and receiving devices and communicates with eh receiving device to ensure that all packers have been transferred correctly and in the right order , if not then the packets can be resent
however, the UDP doesn’t check but this saves time so is good for live video streaming
