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Computer Science - Coggle Diagram
Computer Science
TCP/IP Protocol Stack
Application Layer: Where network applications, like web browsers and email programs, operate. Protocols operating on this layer: HTTP(S), SMTP, IMAP, FTP.
The user directly interacts with this layer.
Transport Layer: Sets up communication between the 2 parties and agrees settings like packet size, etc. Protocols operating on this layer: TCP, UDP. Figuring out how to wrap the packets.
Internet Layer: Addresses and packages data for transmission; sets up routing across the network. the IP protocol operates on this layer.
Wrapping and addressing the packets, ready to send.
Link Layer: The network hardware operates on this layer, eg the Network interface card (NIC). OS drivers are also present on this layer.
Where the packages are sent.
Network Security
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Encryption: Encoding a message so it cannot be understood by anyone but the intended recipient. Prevents 3rd parties accessing the data.
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Firewall: Application that monitors network traffic and decides whether to block it based on a defined set of network security rules.
Ports: Allow certain types of data through the firewall. The more of these kept closed, the more secure the network.
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MAC Address Filtering: Every computer has a unique Media Access Control (MAC) Address. Networks can be made more secure through a blacklist of banned MACs or, better, a whitelist of allowed MAC addresses, with no others being allowed to enter. Based on a physical property of the computer- can be circumvented by changing devices.
Data Representation
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Hexadecimal: 0 to 16, using A-F for 1 to 15. Often used in computing due to its efficient representation of binary.
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Decimal: 0 to 9.
Hex-Decimal: Multiply each value in the hex by the relevant power of 16, divide the decimal by 16 and convert the remainder.
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