Network protocols are the rules and standards that govern how data is transmitted and received over networks. They ensure reliable communication between devices across different networks and systems — think of them as the grammar rules of the internet's language.
The OSI model divides network communication into 7 layers — each with a specific job. Data flows down through all layers when sending, and back up through all layers when receiving.
| # | Layer | Job | Protocols |
|---|---|---|---|
| 7 | Application | User interface, services | HTTP, FTP, SMTP, DNS |
| 6 | Presentation | Data translation, encryption | SSL/TLS, JPEG, MPEG |
| 5 | Session | Session management | NetBIOS, RPC |
| 4 | Transport | End-to-end delivery | TCP, UDP |
| 3 | Network | Routing, addressing | IP, ICMP, ARP |
| 2 | Data Link | Physical addressing | Ethernet, WiFi |
| 1 | Physical | Raw bit transmission | Cables, Radio, Fiber |
Hypertext Transfer Protocol — the foundation of data communication for the World Wide Web.
Use cases: Web browsing, REST APIs, file downloads
Transmission Control Protocol — reliable, ordered, connection-oriented delivery with error checking.
Use cases: File transfer, email, web browsing
User Datagram Protocol — fast, connectionless, minimal overhead. Speed over reliability.
Use cases: Gaming, streaming, DNS queries
Open Systems Interconnection — 7-layer conceptual framework standardizing how networks communicate.
Use cases: Network design, troubleshooting
| Protocol | Layer | Connection | Reliability | Speed | Use Cases |
|---|---|---|---|---|---|
| HTTP | Application (7) | Stateless | Depends on TCP | Medium | Web browsing, APIs |
| TCP | Transport (4) | Connection-oriented | High | Slower | File transfer, email |
| UDP | Transport (4) | Connectionless | Low | Faster | Gaming, streaming |
Each protocol deserves its own spotlight. Click any card below to dive into the full reference guide.