Networking

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3.1.1 Identify types of networks

LAN

VLAN

WAN

SAN

WLAN

VPN

PAN

P2P

How has networking technology change in the last five years and what has been the impact on society?

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3.1.8: Explain why the speed of data transmission can vary

Delays are cause by:

Nodal Processing

Error checking

Addressing

Slows down processing

Queuing

Queuing at the node

Network load has impact

Propagation

The time for the data to travel

Dependant on the medium (copper is slow, weather)

End point processing

Not technically a delay in data transmission but the end user can't distinguish the difference.

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3.1.9: Explain why compression of data is often important for transmission across a netowrk

Makes transmission faster.

Makes transmission more secure because if it is compressed the file in unreadable in parts or you can add passwords.

Makes data storage easier on the other end.

Smaller files processed by web apps easier

Lossy

Smaller but loses "non critical" information which may reduce the quality or usability of the data.

Lossless

Uses binary tricks and algorithms to retain al information in a smaller file.

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3. 1.10: Oultine properties of different transmission media

Copper wire: Cat5e Cat6 Cat7 Sends pulses of electricity

Speed: 100 mbps-1gbps

Reliability: Incredibly reliable over short distances (less than 1 km)

Cost: Cheap

Security: As secure as a physical connection can be. It becomes about physical security of the premises.

Fibre optic: Glass or plastic Sends pulses of light

Speed: 10 gbps

Reliability: Incredibly reliable over short distance (50 km)

Cost: Expensive

Security: As secure as a physical connection can be. It becomes about physical security of the premises. A bit more secure than copper wire because it requires fewer connection where it can be hacked.

Wireless: Wifi, bluetooth: Broadcasts radiowave signals.

Speed: 100 gbps. Wifi has a lot more overhead because there is more processing involved. It also suffers congestion if more users connect to it than it's capacity can handle.

Reliability: Quite reliable (20 meters)

Cost: Somewhere in between

Security: Much better than it was ten years ago. Pretty good.

Satellite

Speed: 100 gbps

Reliability: Less reliable. Dependant on weather and time of day.

Cost: Somewhere in between

Security: Pretty good

Latency

is the speed that something can get there.

A small latency is good.

Bandwidth

is how much data can be transmitted

A large bandwidth is good

FTTP (Fibre to the premises): A fibre optic cable that goes directly to each home.

FTTN (Fibre to the node) A fibre optic cable that goes to the node which then splits off to copper wire to each home.

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How has networking technology changed in the last five years and what has been the impact on society?

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http://computer.howstuffworks.com/vpn7.htm

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3.1.11:Explain how data is transmitted via packet switching

Packet switching: breaking down data into packets.

Packets will likely not go the same route even if they are going to the same place. These packets may not come back or come in in the correct order.

Router: Much faster than a switch . Smaller environment and better technology.

Switch: Distinguishes where the message is directed to and broadcasts to everyone if it does not recognise it's direction. It has more ports.

Hub: broadcasts messages to all devices. They are cheap because they need no infrastructure.

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Recursion

Algorithm: online of the way a program runs.