OSI model
The OSI model is a means of grouping protocols by the layer at which they operate.
| Layer | Name | Description | Examples | |||
|---|---|---|---|---|---|---|
| 7 | Application | Primary interface for working with a communication system | FTP, [[HTTP | net.http]], SSH | ||
| 6 | Presentation | Formatting and presentation of data; e.g. encoding, data compression, encryption/decryption | ASCII, PNG | |||
| 5 | Session | Managing communication sessions (continuous transmissions between two nodes) | SYN, ACK, source and destination ports | |||
| 4 | Transport | Reliable transmission of data segments between points on a network, including segmentation, acknowledgement and multiplexing | [[TCP | net.tcp]], [[UDP | net.udp]], [[port numbers | net#common-port-numbers (Private)]] |
| 3 | Network | Structuring and managing a multi-node network, including addressing, routing and traffic control | IP ([[v4 | net.ipv4]] and [[v6 | net.ipv6]]), routers | |
| 2 | Data link | Reliable transmission of data frames between two nodes connected by a physical layer | [[Ethernet | net.ethernet]], MAC, switches | ||
| 1 | Physical | Transmission and reception of raw bit streams over a physical medium | [[Ethernet | net.ethernet]], Twisted pair, optical fiber, RJ45 |
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