Software → Computer Networks
OSI Model
A seven-layer reference model for reasoning about network communication responsibilities and protocol boundaries.
Why it matters
The OSI Model gives engineers a common vocabulary for locating network behavior and diagnosing failures.
The seven layers
- Physical moves signals.
- Data Link moves frames on a local link.
- Network routes packets between networks.
- Transport provides end-to-end delivery.
- Session coordinates conversations.
- Presentation represents and transforms data.
- Application exposes network services to software.
Practical use
Real protocols do not always fit neatly into one layer, but the model is valuable for separation of concerns and troubleshooting.