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Networks (Hardware (Network Interface Card: creates the signals to send…
Networks
Hardware
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Hub: connects multiple devices to a network, sends data all over the network
Switch: connect devices on the network, sends data only to intended device
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Modem: converts analogue to digital and digital to analogue, changes the mode of the data
Topology
Bus: single cabled back bone with all devices (servers, computers, printers) connected, has terminators at the end
Ring:
All devices are arranged in a circle, each responsible for passing to next node
Star:
Most common way to set up a network, all connections are to a central device
Mesh:
All nodes are connected to each other, allows for self-healing (find an alternative route) if link is broken between nodes
Partial mesh: most nodes are connected usually those which have the most traffic are connected to a number of others allowing for self healing
Data
IP Address: a number which identifies a device on a network
MAC Address: a set number linked to a device
Protocol
set of rules / standards which data is sent by eg: TCP / IP which is the transfer control protocol / internet protocol
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Data packets have
Header: IP Sender and receiver, number of packets and packet number
Payload: Data
Trailer: end of packet marker and check for data errors
Network Policies
Companies have an Acceptable Use Policy which covers
polite language
not revealing passwords
not using for anything other than work purposes
not downloading programs
not sending anything offensive
not revealing personal information
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Types of Network
Peer to Peer:
All nodes act as a client and a server, equal status.
Disadvantages:
Back ups complicated
Machines can be slow
No network wide security in place
Client Network
Have a central server and other nodes are clients requesting information which is sent by the sever.
Advantages:
central Security
Network upgrades / supervision
Back ups can be done
Less data collisions
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Network Classification:
LAN: Local Area Network - uses cables
WAN: Wide Area Network - uses satellites
MAN: Metropolitan Area Network
PAN: Personal Area Network
VPN: Virtual Private Network
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Compression: reduces file size
Lossy: loses parts of the data when compressed, fine for a video as can still watch but not a text file
Lossless: does not lose any quality so good for text files
Web Standards:
GIF - Graphic Interchange format - images
JPG / JPEG's - images
PDF - documents which can be downloaded and not altered
MPEG - videos
MP3 - audio ONLY