30. Networking Models
Networking models are standardized frameworks that explain how different hardware and software systems communicate so they can share information and work together.
Networks combine many parts: communication devices, storage, processing, security tools, input/output devices, operating systems, applications, services, data, and people. Models help organize this complexity so communication is reliable and consistent.
Why networking models exist
They are used to:
- Provide reliable, managed communication between hosts and users
- Separate network functions into layers
- Use packets as the method of communication
- Standardize addressing, routing, and control
- Allow higher layers to add features and services on top of basic networking
- Stay vendor-neutral and support scalability and resilience
Layered approach (OSI idea)
Networking is split into layers so each layer has a clear job. The OSI model has 7 layers:
- Physical
- Data Link
- Network
- Transport
- Session
- Presentation
- Application
These can be grouped into:
- Lower layers (1–4): move data across the network (bits → frames → packets → transport)
- Upper layers (5–7): manage sessions, data format, and applications that users interact with
Upper vs Lower layer roles
- Lower layers: handle sending raw data over the medium, framing it, and addressing/routing it.
- Upper layers: manage the connection/session, data formatting/translation, and application communication.
Main Idea
Networking models break communication into layers to standardize how devices communicate and to make networks reliable, scalable, and easier to manage.