Networking¶
How computers exchange data: from signals on a wire or radio channel up to the applications that use them.
Layers¶
Networking is organised in layers. Each layer uses the services of the one below and offers services to the one above.
| OSI layer | TCP/IP model | Unit of data | Examples |
|---|---|---|---|
| 7 Application | Application | message | HTTP, DNS, SSH |
| 6 Presentation | Application | message | TLS, encodings |
| 5 Session | Application | message | |
| 4 Transport | Transport | segment / datagram | TCP, UDP, QUIC |
| 3 Network | Internet | packet | IPv4, IPv6, ICMP |
| 2 Data link | Link | frame | Ethernet, Wi-Fi (MAC + LLC) |
| 1 Physical | Link | bits | copper, fibre, radio |
Pages¶
- MAC layer: addressing, frames and how devices share a medium