1.3 – Computer networks, connections and protocols Flashcards
(80 cards)
What is a network
two or more devices that are connected so that they can communicate with each
other.
Stand-alone device
A device that is not connected to any other device and ‘stands’ on its own
Advantages of networks
-files can be shared
-peripherals can be shared
-an internet connection can be shared
-users can access files and data from any device on the network
-users can communicate with each other over the network
-Software updates can be rolled out all in one go across all the devices on the network,
saving time
Disadvantages of networks
There is an increased security risk to data. Devices are
easier to hack when connected on a network
Malware and viruses can spread easily and quickly between
devices on the network if appropriate security measures are not put in
place
If the server for the network fails, the whole network may go down
If there is a large amount of data travelling over the network, the
devices on the network may slow down
Networks can be expensive to install and maintain e.g. the
buying and installation of the hardware, and hiring someone
to monitor the network can be expensive
What is a LAN
-local area network
-A LAN is a network that covers a small geographical area, such as one building or two
buildings close together
examples of LAN
A school
A house
A corner shop
what is a WAN
-wide area network
-A WAN is a network that covers a large geographical area, such as a city, country, or the
world. They are a series of LANs all connected
examples of WAN
The internet
An international bank
ATMs (Automated Teller Machines) that dispense money
How does bandwidth affect the performance of a network
-the amount of data that can be sent and received successfully in a given time
-more bandwidth means more data having to be sent so slower network speed
How does the number of users affect the performance of a network
Too
many users on the network will mean more of the bandwidth is being spread out to try and
meet all the users’ needs. When there is not enough bandwidth to manage all the users on the
network, the network will slow down.
How does transmission media affect the performance of a network
A
wired network for example has a higher bandwidth compared to a wireless network, due to
less interference. Using fibre optic cabling rather than copper cabling will have a higher
bandwidth, due to less interference again.
How does error rate affect the performance of a network
This refers to the number of errors that occur when data is transferred. The higher the error
rate, the more frequently data has to be resent before arriving safely and correctly.
for example:
if the user is far from the WAP
if the type of media is wireless
How does latency affect the performance of a network
This is the delay from transmitting data to receiving it. This can be increased by not having
the correct network hardware to direct traffic around the network appropriately, causing
‘traffic jams’ and therefore slowing data down.
What is a client-server network
the client makes a service
request to the server. The server then sends the
requested information to the client
There is a central dedicated server (or group of central dedicated servers in larger
businesses), and all clients request information from them.
What is a peer-to-peer network
In this model there is no central dedicated server. Instead, all the devices on the network
take on the responsibility of being a server, storing files and
handling service requests. Each device has an equal
responsibility for providing data when requested
security,management ,dependency,performance,backups of client-server networks
sec-controlled by server and is consistent throughout each device
mana-server manages the network but needs specialised network engineers to maintain.
depend-all dependent on server,if goes down,whole thing goes down
perform-can be upgraded to improve and maintain performance,but is expensive
backups-data is backed up on the server incase of a data breach
security,management ,dependency,performance,backups of p2p networks
sec-all clients are responsible for sec of network and themselves,may not be consistent
management-anyone can set up and be responsible for it as no central managing
depend-if one goes down,others still up as not dependent to one central server
perform-if one is slow others are slow ,but upgrading is cheaper than client server
backups-must be done individually.This can lead todata being lost not backed up, or media containing the backups being lost
What hardware is required to make a LAN
These pieces of hardware are the:
NIC (Network Interface Controller/Card),
Wireless Access Point,
Switch,
Router,
Cabling.
NIC(network interface card)
connects a device to a wired or wireless
network and is built into the device. It uses protocols to ensure the
communication between the device and network is consistent.
WAP(Wireless access point)
allows devices to connect to a network
wirelessly, without the need of any cables.
switch
sends data around a network. A switch however sends
data only to the correct device on the network, rather than all the devices
on the network. This is because they can read the data packets being sent
and therefore work out where the receiver is.
Hub
used to also send data around a network. A hub however sends
data to all devices on a network, rather than just the correct device. This
is therefore not good for security, as it allows any device on the network
to intercept a data packet and potentially steal its contents.
router
sends data between multiple networks. You cannot
connect to a WAN such as the internet without a router. A router often
has a modem built into it now, which enables you to connect to the
internet. A router uses an IP Address to direct traffic between
networks.
What is an IP address
-IP Addresses are used to
allow data to be directed around the internet from senders to the correct receivers.
-An IP Address is unique to each device connected to the internet
