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Networks 1 - Coggle Diagram
Networks 1
Protocols
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A network protocol is a set of rules for how devices communicate and how data is transmitted across a network. They are needed because they allow manufacturers to create products and programs compatible with other products and programs
Communication protocols specify how communication between two devices must start and end, how the data must be organised and what the devices must do if data goes missing
MAC addresses are used by ethernet protocol on LANS. The LAN reads the MAC address and directs the data to the right device
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IPV4 is 32 bits, IPV6 is 128 bits. Both have hexadecimal numbers.
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Transmission protocol - sets rules for how devices connect to the network. It's in charge of splitting data into packets and reassembling packets back into the original data once near recieving device. Also responsible for checking if data is correctly sent and delivered
Internet protocol - responsible for directing packets back into their destination across the network.
HTTP - Used by web browsers to access websites and communicate with web servers. S just encrypts everything.
FTP - file transfer protocol - used to access, edit and move files between two devices on a network.
POP3 - post office protocol version 3 - Used to retrieve emails from a server. The server holds email until downloaded and then deletes from server.
IMAP - internet message access - Used to retrieve emails from a server. Server holds email until deleted because you only download a copy. Used by web clients.
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Toplogies
Star
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In star topology, all devices are connected to a central switch or server that controls a network..
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Pros
- If a device fails or cable is disconnected, the rest of the network is unaffected.
- Simple to add more devices.
- Better performance because all devices can transmit data at once and there are a few data collisions
Cons
- In wired networks, every device needs a cable in order to connect to the central switch or server. This can be expensive, e.g. for an office builiding with 50 terminals.
- If there is a problem with the switch or a server then the whole network is affected.
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Ring
In a ring topology, data moves in one direction around in one direction around the ring preventing collisions.
But only one device can send data at a time and data passes through many devices before reaching its destination.
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Mesh topology
Devices are connected to each other without needing a central server or a switch but send data along the fastest route available. They can be wired or wireless.
Advantage:
- no single point where the network can fail, the data is just sent along a different loop
Disadvantage:
- wired mesh networks are often very expensive as the cables used the connect them cost a lot of money.
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