Computer networks, connections and protocols Flashcards
What is a stand-alone computer?
A computer not connected to another
What is a network?
A set of connected computers and other devices in order to share resources - hardware, software and data
What is the internet?
A worldwide collection of networks.
Using the same protocol
This is called IP, or Internet Protocol
Use packet switching to transmit data.
It is the largest WAN in the world.
What are the advantages of having a network?
share data very easily
work collaboratively
share device, e.g printers
share single internet connection
What is a LAN?
Local Area Network
Confined to a single geographical area
Infrastructure normally owned by the user
Examples: home, school
What are the advantages of a LAN?
Share and exchange of information e.g updating databases
Data and software can be held anywhere and can be accessed anywhere
Device sharing - save money
Security
Software sharing and mainetnace
Data is easy ot back up as it is stored centrally on the server
LAN has its own infrastructure/cables/network
What are the disadvantages of a LAN?
Expertise needed - complicated to manage outsourcing (e.g the school uses the company Eduthing)
Need for increased security - viruses may be able to infiltrate the network and infect every computer
What are the different hardware required to connect a stand-alone computer to a LAN?
NIC, Router, Switch, Transmission media, WAP
What is a WAN?
WAN is a Wide Are Network
Covers multiple geographical areas
A LAN connected to other LANs
A network with multiple sites e.g network of world wide branches of a business
WAN uses external hardware/infrastructure/cables/network e.g supplied by BT
What does a WAN uses to connect two or more remote locations?
cables, telephone lines, satellites or radio waves
What are some organisations that might use a WAN?
organisations such as universities and schools may have a no. of geographical locations (each one will have its own network, when these networks are joined together they create a WAN)
Large companies with many offices e.g banks
Governments which have employees in many locations
Research organisations which are located in more than 1 place.
What is a Network Interface Card? (NIC or WNIC)
Hardware which contains circuits which allow computers to communicate over a network either using cables or wirelessly
Usually integrated on motherboard of a computer
assigned a unique MAC address
What is a router?
A router sends data between networks.
- receives packets of data from a network/internet
- uses routing table to decidee where to send packets
- forwards packets of data from one network to another in the most efficient way
- connects networks to the internet using IP addresses
You cannot connect to a WAN without using a router.
A router uses IP (internet protocol) addresses to control traffic.
What is a switch?
Allows multiple devices to connect to each other in a LAN.
Sends and receives data between computers on a LAN
Device learns the MAC address (hardware address) of the computer connected to each port
Inspects destination address of data packets coming in
Sends packets of data to the correct recipient directly based on their address
Buhs, by comparison, will send the data to all the connected computers
What are the similarities and differences between a router and a switch?
Similarities:
both connect devices
receive data from devices
transmit data to its destination
Differences:
switch uses MAC addresses
Router uses IP addressses
S connects computers in a LAN
R connects networks to the internet/different networks in a WAN
R stores IP addresses of devices attached in routing table
S looks for correct MAC address before sending
What is ethernet?
Standard communications protocol embedded in hardware devices: ethernet describes how devices should format data ready for transmission between computers on the same network.
Basically a standard for networking technologies.
used for building wired LANs
ethernet cables connecct NIC in a device to central switch/hub
higher bandwidth available for a cost
What is transmission media? What is unbound and bound transmission media?
Transmission media:
The way the communication is sent through a network.
Bound - uses physical links e.g cables to transmit information
Unbound - no physical links: uses microwave, infrared or radio signals to transmit information
What are the benefits of using copper cables (UTP - unshielded twisted pair) for transmission media?
Connections between desktop computers and a switch or a router are usually achieved with a wired connection
- wired connections ensure maximum bandwidth, security and reliability
- UTP the wires a twisted aroudn each other to reduce interference
- normally there is a set of wires for transmission and a set of wires for receiving
- the grade of copper and insulating material affects the quality of the overall cable and therefore bandwidth
What are the advantages of using fibre optic cables as transmission media?
uses light to transmit data
cover much longer distances and greater bandwidth than copper due to reduced interference
the backbone of the internet uses fibre optic cables
used in high-traffic connections such as between switches and remote buildings
Describe a star network topology.
Most popular wired type of network
central switch
all devices connected to central switch
the switch is intelligent and makes sure traffic only goes where it is intended
if a single cable breaks only that computer is affected
the switch however is still a serious single point of failure
What are the advantages and disadvantages of a star network topology?
Advantages
Fast transfer data as there are fewer data collisions
if one cable fails the other workstations are not affected
disadvantages
requires additional hardware such as a central switch
if the central device fails the whole network goes down
Describe a full mesh topology.
Every device is connected to every other device