fundamentals of computer network Flashcards
what is a computer network
two or more computers - or other electronic devices - that are connected together for the purpose of communication
what is the internet
group of inter- connected networks
what are the advantages and disadvantages of a computer network
- ADVANTAGES:
resource sharing - printers/scanners and internet connections can be shared
Files can be accessed through any computer in the network without physical transfer eg USB
Data is easy to back up as it is stored centrally on the network
DISADVANTAGES
- security risk - Networks are vulnerable to cyberattacks such as hacking .
Sensitive data can be compromised if not secured properly.
- purchasing network hardware eg servers, routers, and switches can be expensive to set up
- If the network goes down, users lose access to files, resources, and services.
what is PAN ( personal area network )
-computer network designed to connect devices within a small range, typically a few meters eg BLUETOOTH
what is WAN ( wide area network )
- connect users and applications in wide geographic areas eg globe
- The biggest example of a WAN is the internet
- these are often under collective or distributed ownership
what is LAN ( local area network )
- connect users and applications in close geographical proximity (same building)
- ## owned and controlled/managed by a single person or organisation.
what are some organisations that might use WAN
- large companies with many offices eg banks
- Governments - which have employees in many locations
- Research Organisations - that are located in more than one place
what are advantages and disadvantages of wireless networks
ADVANTAGE OF WIRELESS:
- easy installation - no need for cables
-Easy to add new devices without extra cabling or physical changes.
- Users can move freely within the range of the network without losing connectivity.
DISADVANTAGES:
- security risk - more vulnerable to hacking and unauthorised access.
- generally slower than wired networks due to interference and limited bandwidth.
-If many devices try to use the same Access point simultaneously, the connection can be very slow
what are advantages and disadvantages of wired networks
ADVANTAGES :
- faster speed - reliable connections compared to wireless.
Suitable for tasks that require consistent high bandwidth (e.g., gaming or video editing). - better security - More secure since physical access to the network cable is required.
Less prone to unauthorised access compared to wireless. - no interference -
DISADVANTAGES:
- Cost - Installing and maintaining cables can be expensive and time-consuming, especially in large buildings.
- complexity - users are tethered to a specific location, limiting mobility.
- aesthetics and practicality are difficult
what are 3 types of cables used in wired networks
fibre optic cables, coaxial cable, copper cable
compare fibre optic with copper cables
FIBRE OPTIC
- very fast connections with much greater bandwidth
- much greater equipment costs and cabling
- signals travel as light waves so Not affected by electromagnetic interference
- Long-Distance Transmission - allows data to travel over long distances without the need for frequent signal boosters. - less loss of signal strength ( typically 1km + )
COPPER CABLES :
- cost effective and cheaper routing equipment
- easier installation
- signals affected by electrical interference
- significant loss of signal over distance ( typically 100m)
when are coaxial cables used and why
what is a topology
the ways in which parts of a system are connected
what are the advantages and disadvantages of star topology
ADVANTAGES:
- fast data transfer to the hub as each wire isn’t shared with other computers
- if one cable fails the other ones aren’t affected
DISADVANTAGE:
- requires additional hardware such as central switch and network cables
- if the central switch fails the whole network goes down
what are the advantages and disadvantages of bus topology
ADVANTAGES:
-less cable to cheaper to install the network
- easier to add more devices as they only need to connect to a central cable
DISADVANTAGES:
- the single cable is shared by many devices so there will be many “collisions” of data if data is sent at the same time
- if the cable is damaged the whole network fails
- any device can view all data on the cable - making it a security risk
how is a star topology connected
- computer and other devices (nodes) are all connected to a central switch
how is a bus topology connected
computer and other devices are all connected to a central coaxial cable
what is connected to the ends of the cable in bus topology
terminators placed at the end of each cable to absorb signals and prevent them from reflecting down the cable
draw a bus topology AND LABEL
draw a star topology AND LABEL
when is it appropriate to use fibre optic cable
- for long-distance communications
- high-speed internet - broadband connections
- high traffic networks - streaming services
when is it appropriate to use copper cable
- LANS
- Short-distance communications
when is it appropriate to use coaxial
- cable tv
- radio frequency
- short distance video transmission
what does network protocol mean
set of rules that determine how data is transmitted over a network.
when is it appropriate to use bus topology
when is it appropriate to use fibre optic cable star topology
what is the purpose and use of ethernet
- ‘ethernet’ - family of standard local networking “ protocols”
- it describes how devices should format data ready for transmission between computer ( nodes ) on the same network
what is the additional hardware needed to connect a stand alone computer to a LAN
- NIC
- switch/hub
- modem
- router
- Wireless Access Point
what is an NIC
- network interface card - provides a connection between the device and the network
what is a switch / hub
- connects together all the computers or devices on the LAN
what is a modem
- required to connect to the internet - usually combined with a router inside a single device
what is a router
needed to route packets to their destination
what is a wireless access point
- connects wireless devices to a network
what is the purpose and use of HTTP protocol
- HTTP - hypertext transfer protocol
- used for accessing and receiving web pages via the internet - these are written in HTML ( hypertext mark-up language)
what is HTTPS used for
- provides an encrypted version of HTTP for more secure web transactions
what is FTP
file transfer protocol - used for sending or receiving files to or from the ftp
What is TCP
- transmission control protocol - breaks up messages sent over the internet into packets
- reassembles the packets at the other end
- detects errors
- resends lost messages
what does the IP protocol do
- internet protocol - routes the individual packets from one IP address to another
what are the 4 layers of the TCP / IP protocol stack
- application layer
-transport layer - internet layer
- link layer
what are the advantages of layers
- they are self-contained - the functionality of one layer can be changed without changing the functionality of other layers
- different hardware or software operates on a particular layer providing interoperatibiiltty between providers and systems
-senders and recievers using different softwares and hardwares can communicate using the same layer protocols
what happens at the link layer
- where the the physical network hardware is located this inludes:
- NIC’S
- cables and WiFi
- OS drivers
what is the internet layer
- responsible for routing packets
what is SMTP
- simple mail transport protocol is an email protocol used for sending emails
