3.5 Networks - full Flashcards
Only need to use this for networks
Node?
Any device connected to a network.
Network topology ?
- incl 2 examples
the arrangement, or pattern, in which all nodes on a network are connected together. There are several common topologies that are in use, but today the most common topologies are:
bus topologies
star topologies
Define network
A network is two or more computers - or other electronic devices - that are connected together for the purpose of communication.
How are computers connected
They are connected by a wired medium such as cables, or by a wireless medium such as Wi-Fi.
Stand-alone
A computer or device that is not connected to a network is called a stand-alone.
Today, many different types of computer are connected to some form of network. As well as PCs, many other devices such as
Today, many different types of computer are connected to some form of network. As well as PCs, many other devices such as smartphones, smartwatches, fitness trackers, car engine management systems, internet-enabled fridges, intelligent personal assistants and media boxes can all be connected.
There are three classifications of network:
local area networks (LANs)
wide area networks (WANs)
personal area networks (PANs)
LAN - spec (2)
- usually cover relatively small geographical areas
- often owned and controlled/managed by a single person or organisation
So what’s a LAN and give examples (6)
A local area network (LAN) is a network that is geographically confined to one building or site. Examples include networks employed by small businesses, small organisations, schools, colleges, universities and in homes.
WAN - spec (3), incl what’s the biggest
- the Internet is the biggest example of a WAN
- WANs usually cover a wide geographical area
- WANs are often under collective or distributed ownership
So what’s a LAN?
What can it cover?
Examples + why/how?
A wide area network (WAN) is a network that is spread over a wide geographical area. It can cover more than one site, or be spread across a country, or even the world.
Organisations that have more than one office or branch, such as banks, tend to use a WAN. The WAN allows the head office to communicate and share data with the sub-offices and branches. Communication is through national telephone infrastructures or via wireless transmission. While each office or branch has its own LAN, they are connected together using the WAN.
The internet is essentially a huge, international WAN.
PAN - define (2) + examples (3)
A personal area network (PAN) is a network that is spread over a very small area. It often covers no more than a few metres and is used to connect personal devices such as a smartphone and wireless headphones or a laptop.
Setting up a PAN using a smartphone is also known as creating a ‘__’ and makes use of limited __ or __ to connect devices.
Setting up a PAN using a smartphone is also known as creating a ‘hotspot’ and makes use of limited Wi-Fi or bluetooth to connect devices.
PAN spec - only what needs to be considered?
Bluetooth
To connect a computer or device to a network, several hardware components are required: (3)
- a network interface controller (NIC) or wireless network interface controller
- a transmission medium, either wired or wireless
- a point to connect to, such as a router, hub, switch or wireless access point (WAP)
What does transmission media do?
Transmission media carry data signals from one computer to another.
What a network interface card?
And a wireless NIC?
A network interface card (NIC) offers an interface port for a wired connection. A wireless NIC provides a radio transceiver for connecting wirelessly.
NICs in different types of devices:
- modern PCs
- mobile devices
Most modern PCs come with a NIC and wireless NIC built-in, providing the option of either connection method. However, mobile devices such as tablets, smartphones and many embedded devices only feature a wireless NIC, giving only wireless connection.
What does a network connection device do?
A network connection device allows computers to connect to a network.
2 types of network connection devices
- switches
- routers
Switches
- what
- how work
- and therefore, good because
- Switches are network devices that record which computers are connected to which ports.
- When traffic is received, the switch forwards the traffic to its intended recipient only.
- This improves network performance by cutting down on unnecessary transmissions from older style networks.
Routers
- what is they
- what they used for
- Routers are one of the most commonly used connection devices.
- They are used to send data signals across the internet.
How do routers work? (2)
- Routers work by collecting knowledge of available routes to transmit data.
- They then determine the most suitable route for sending data.
Routers in homes:
- additional hardware (2)
Routers are also commonly used in homes.
- These types of router usually contain additional hardware that allows a network to be formed.
- Additionally, they contain a modem, which allows users to connect to the internet.
Define modem
Meaning ‘modulator/demodulator’. Allows computers to connect to a network over a telephone line.
What transmission media do?
Two types?
- Transmission media carry data signals from one computer to another.
- Media are either wired or wireless.
In modern networks, wired media use either (2)
In modern networks, wired media use either twisted copper wiring, or fibre-optic cable.
Compare Twisted copper wire with Fibre-optic cable:
- cost
TCW:
- Cheaper to purchase and install
F-O C:
- More expensive to purchase and install
Compare Twisted copper wire with Fibre-optic cable:
- maximum transmission speed
TCW:
- Up to 1 gigabit per second
F-O C:
- Over 40 terabits per second
Compare Twisted copper wire with Fibre-optic cable:
- maximum distance for reliable connection
TCW:
- Up to 100 metres
F-O C:
- Over 2 kilometres
WAP
- what it does, using what
A wireless access point (WAP) uses a radio transceiver to allow wireless connections to a network.
So how a WAP actually works (3)
- A wireless access point (WAP) uses a radio transceiver to allow wireless connections to a network.
- In effect, the WAP creates its own wireless network, which devices connect to.
- The WAP then sends the wireless traffic it receives on to the main wired network.
Another use of WAPs + 2 examples
- WAPs can also be used to extend the range of a wireless network.
- In this case, the WAP can either receive or transmit traffic to other WAPs, or it can be connected via a cable to the main network.
Where ethernet (copper) uses ___, fibre optic cables transfer data using __.
Where ethernet uses electrical signals, fibre optic cables transfer data using light.
The main adv of fibre optic
- also how are they limited
Fibre optic cables offers extremely high bandwidth (they can transfer a lot of data in a given time). So much bandwidth, in fact, that fibre optic networks are usually limited by the equipment connected to the cable rather than the cable itself.
what is a transceiver
A device that transmits and receives messages.
Wired networks:
- how identified
- most often used
- Wired networks are identified by their use of physical wiring to connect devices.
- They are most often used for office networks or for devices that are unlikely to move as the cables limit the ability to move away from the connection point.
Wireless networks:
- how do they carry signals
- tell me about these signals (2)
- Wireless networks use radio waves to carry signals.
- These signals are limited in range - usually up to 50 metres - but are subject to interference.
- They can also be blocked by walls.
What is a wireless network ideal for and why?
they are ideal for mobile devices as a device can connect to a network as long as it is in the range of a wireless access point (WAP).
Wired vs wireless networks:
Cost
It is more costly than Wi-Fi to install in a building
Only needs a Wireless Access Point to set up, so is cheaper.
Wired vs wireless networks:
Connections
Can only allow a limited number of people to connect at any one time
Allows hundreds of people to log in at the same time.
Wired vs wireless networks:
Interference
It is immune to radio interference
Affected by radio interference