Network model layering
1. The physical
- Electrical, mechanical, process, and functional specifications are defined for starting, maintaining, and shutting down the physical link layer
- It’s binary transmission
2. Data link layer
Access to the medium
- Define how data is formatted for transmission and how access to the network is controlled
- Support error detection
3. The network layer
The data transfer
- Routed packet
- Choose the best path to transfer the data
- Support for logical addressing and path selection
4. The transport layer
Terminal to terminal communication
- Ensure the reliability of data transmission
- Create, maintain, and terminate virtual circuits
- Through error detection and recovery
- Information flow control to ensure reliability
5. The session layer
Interhost communication
- Establish, manage, and terminate sessions between applications
6. The presentation layer
Representation of data
- Make sure the receiving system can read the data
- Format speech data
- Set up the data
- Negotiate the data transfer syntax for the application layer
- Provide encryption
7. The application layer
Network processes access the application layer
- Provides network services for application processes such as E-mail, file transfers, and so on
- Provide user authentication
