Networks Flashcards
What is a network?
Anetworkis a group of devices connected together so they can communicate with each other and share resources.
How large is a network?
Networks can vary hugely in terms of size and complexity. Mobile hotspots and the internet are examples.
State benefits of a network.
- Share data and information
- Communicate using email, messaging, video conferencing
- Work collaboratively using work-based software, virtual meeting tools, etc.
- Share hardware e.g. printers
- Use centralised support and maintenance
- Socialise with one another
What is a standalone computer?
It “stands alone”, without connections to other computers or networks.
What are the benefits of a standalone computer?
They are not considered useful today, but can be used to store sensitive files as they can only be hacked manually, or to test the severity of ransomware/viruses.
What’s a WAN?
Networks that are connected over a large geographical area are known as Wide Area Networks (WANs).
An example of a WAN
The largest example of a WAN is the internet. Examples of WANs are online banking.
What organisation specific hardware does a WAN involve?
- Organisations that run their own WANs will often lease bandwidth from telecommunications companies. They own this and have full control of the network.
- Others cannot use its’ infrastructure, making it secure. However, the infrastructure can be expensive to install and maintain.
What’s a LAN?
Networks that span a smaller geographical area that are contained within a single site or building are known as Local Area Networks (LANs)
What does the “L” refer to in “LAN”?
‘Local’ doesn’t refer to a specific geographical area, such as neighbourhood, city, or region.
What organisation specific hardware does a LAN involve?
In larger organisations (schools, colleges) infrastructure (cabling and network communication devices) will be owned and maintained by the organisation.
How do addresses work on a LAN?
- Each device on a network has a unique identifier, which is usually its IP address.
- The first part of this address is thenetwork ID, which will be the same for all of the devices on the network.
- Each device in a network needs a unique address so that connections can be made to it.
What is IPv4?
The fourth version of internet protocol IPv4 allows 4.3b addresses. It uses 32-bit encoding.
Ran out of addresses for the world
What is IPv6?
The sixth version of internet protocol
IPv6 allows for 340 * 10^38 addresses. It uses 128-bit encoding. They can therefore address a greater number of unique devices.
What is an internet protocol?
Protocols are sets of rules (agreed standards) that govern the communication within devices.
For two devices to communicate, they must use the same protocol.
What is bandwidth?
Bandwidth is the maximum amount of data that can be transmitted over a connection. It is a measurement of capacity measured in bps (bits per second)
What is latency?
Latency is the time taken for a transmission to reach its destination. It is measured in milliseconds.
What is ping?
Ping measures latency by making a transmission and tracking the time it takes to move from the server and back again.
What are the bits per second conversions?
That
What are the bit conversions?
That 2
What is the equation to estimate transmission times?
That 3
What is wireless transmission?
Microwaves and radio waves are frequently used to transmit data. This involves converting the binary data into an electromagnetic wave using a specific protocol.
Wi-Fi and Bluetooth are examples of the protocols that govern the conversion of data.
What are some negatives concerning wireless transmission?
- Generally the range of wireless transmission is limited to a few metres.
- It is easily interrupted by other signals or physical obstacles.
- It has much lower bandwidth than wired connections which makes transfer slow.
- Security is a concern as wireless signals can be intercepted by others.
What is a WLAN?
- WLANs are Wireless Local Area Networks.
- You probably have a WLAN at home.
- If you use Wi-Fi to connect your devices, that’s a WLAN.
What is a WAP?
- In a WLAN, there will be a wireless access point (WAP) which sends and receives wireless transmissions to and from the other devices.
- A WAP is usually part of a box you call the broadband router.
- The router will be connected (usually wired) to an internet access point in order to connect the WLAN to the internet.
Wired VS Wireless - Battle 1
Installation
WIRELESS WINS
+ Not every device needs a dedicated cable, cutting down cabling costs
- Cables still need to be installed in ceilings and floors to get from the WAP to a switch
- WAPS need to be purchased
WIRED LOSES
- Wired may be more difficult as every device needs a dedicated cable
- Bugs are more difficult to diganose as all cabling needs inpection
Wired VS Wireless - Battle 2
Flexibility
BOTH SUCK
- Wired cannot move beyond the area covered by the cable
- Wireless cannot leave a 2m radius
Wired VS Wireless - Battle 3
Range
WIRED WINS
+ Transmission over longer distances as copper media is more effective
- Wired may need repeaters or boosters greater than 100m as signal depreciates
WIRELESS LOSES
- Quality easily lost through walls, floors, barriers between WAP and node
- Repeaters and boosters required due to small range
Wired VS Wireless - Battle 4
Bandwidth
WIRED WINS
+ Higher bandwidth as copper media has better signal transmission than air
WIRELESS LOSES
-
Wired VS Wireless - Battle 5
Latency
WIRED WINS
+ Less susceptible to interference from outside network due to cables having layers of covering
WIRELESS LOSES
- More susceptible to interference from outside networks as radio waves disperse over large distances, slowing data transfer
What is topology?
The design/layout of a network
Bus
A central node with stops coming off it
Pros of bus topology
New devices can just be attached to the central node
Cons of bus topology
Decreasing latency down the node
→ Everything stops off at each computer
Hacking poses a more serious threat
→ Each device has access to all traffic
Star
A central switch with spokes coming off it
Pros of star topology
Far more secure if there is an intrusion
→ Data only passes through the switch and the computer
→ Each PC only recieves its’ own traffic
Higher latency
→ Only one journey straight to each computer
Cons of star topology
Limited amount of connections based on amount of ports in switch
If the switch fails, all PCs connected are stranded - Central point of failiure
Full mesh
All nodes connected to each other
Pros of full mesh
Fault tolerance
Reasonably secure
→ Traffic takes shortest route to get to its destination
Cons of full mesh
High cabling costs
Partial mesh
Some nodes connected
Pros of partial mesh
Reasonably secure
→ Traffic takes shortest route to get to its destination
Cons of partial mesh
Computers cannot talk to each other easily
→ Have to move through other computers reducing latency and bandwidth
Where is bus topology used?
a small, cheap and often temporary network is needed that does not rely on very high data-transfer speeds. They may be used in locations such as a laboratory or office.
Where is star topology used?
Home networks
Where is a mesh topology used?
Home automation systems
How is data transmitted on a fibre-optic cable?
A series of glass shards that allow light waves to move down them
Define the World Wide Web
The service hosted on the internet to provide webpages
Define the Internet
Physical devices that make up all networks connected across the world
What do you need within a WAP to connect to the internet?
Switch
Modem
Router
What is the internet backbone?
Fibre-optic cables that connect continents/countries under the sea with a high bandwidth
