Network Security Flashcards
What is a network?
a system that allows computer systems to communicate and share resources with eachother
advantages of network?
allows connection to internet
allows connection through other devices
allows sharing of files
-multiple users can collaborate
-access files from any computer on network
store user accounts
software updates on many devices
disadvantages of network?
if one server goes down the whole network does too
if too many people are on the network it becomes slow
easy go back
easy go put malware into
define LAN
Local area network- collection of devices connected together in a small geographical area
eg ethernet, routers, servers
define WAN
Wide area network- devices connected together in a large geographical area or even the world
eg satellite or internet
what effects the performance of networks
number of users: too many make it slow/ if there is not enough bandwidth for the data
data collision: when 2 devices on a network transit data at the same time on the same channel
transmission media: wired give better performance than wireless
fibre optic have higher bandwidth than copper
what effects performance of networks
bandwidth: amount of data that can be sent and received in a given time on transmission media ( measured bits per second )
interference: walls in houses or steel beams can interfere with wireless signal
what are the 2 network types
client-server
peer to peer
what is a computer that is not connected to a network called?
standalone computer
what is a client sever network?
network relies on a central server
all clients/ devices request services from the server
additional hardware is needed eg high power servers
what is a peer to peer network
all computers can act as a client or server so all have equal status
all devices can request and provide network services
no additional hardware or software requirements
advantages of client server networks?
users can easily share data that is centrally stored
backups are easy to do and controlled centrally
network is easier to manage
server is reliable and always turned on
easier to keep track of files stored centrally
disadvantages of client server?
client server are more expensive because of the servers
specialist network operating system needed
IT specialists required to manage it
server dependency so if server fails, client loses access
if too many clients try to access at once it becomes overloaded
advantages of peer to peer
easy to maintain
don’t need expensive hardware
don’t need expertise
not dependent on a server
if a single device fails, the network will still work
disadvantages of peer to peer
no centralised management
updates need to be installed individually
backups are complex
duplicate files are created when copying across device
peer machines are less reliable if one fails data can be lost
when other devices access them, peer machines are prone to slow down
what is a wireless access point WAP
allows wireless enabled device to access the network without cables
can have a wireless router / switch
included connections through wifi and bluetooth
province internet access in public areas
uses 2.4ghz and 5ghz
advantages and disadvantages of wireless access point WAP
adv: avoid needing to use cables
disadv: lower bandwidth than wired
more security issues
what is a router
directs data in a network
receives packets
sends packets of data over network
assigns IP addresses to devices
identifies most efficient paths to destination
maintains routing table
what is a switch
connects devices together in a network
how does a switch work?
recieves data from all devices
directs data to destination
stores addresses of device connected in a table( IP address )
uses MAC address of device connected to identify devices
if the destination address is not recorded then messages are sent to all devices
what is a network interface card NIC
allows a device to connect to a network
allows data packets to travel to and from computer
each nic has unique mac address
can be wired or wireless NIC
wired NIC are built into motherboards
wireless network interface controller WNIC is for wireless networks
What are the 3 types of transmission media
copper cables UTP
fibre optic
coaxial cable
What are copper cables UTP
unshielded twisted pair
twisted to reduce interference
4 cables twisted together
known as cat5/6 or twisted pair
more secure than wired connection
cheap and flexible so easy install
most common type of network cable
connect computer to switch
what is a fibre optic cable
data transmitted as light
data travels at speed of light
higher bandwidth than copper cables
expensive compared to others
less interference than copper
transmit over large distances with no signal loss
what is a coaxial cable?
made from a single copper wire
surrounded by plastic used for insulation
around the plastic layer is a metallic mesh for shielding
entire cable is surrounded by plastic
older standard of networking
what are the types of network topology
mesh network- where some or all of workstations or devices are connected directly to eachother or the one they exchange most data with (not same as peer to peer)
star network- each device connected by a cable direct to server. usually layout for schools and offices because they are the most reliable
advantages of star topology
simple to add more devices to network
less cables needed
reliable - one cable broken won’t break the rest
no collisions between devices so higher performance
no unnecessary data
easier to install
disadvantages of star topology
network fails if switch fails
expensive to install because of most cables
extra hardware needed
if a switch fails the network fails
performance on network is dependent on central switch
