OSI Reference Model

Osi:open System interconnection Open Systems interconnect
Birth date: The 1970s
Development Organization: ISO (International Organization for Standardization)

Historical reasons for the OSI Reference Model:
International hope that different manufacturers of products can communicate with each other.

Features: Layering
Definition of a layer: a logical grouping of functionally similar functions during communication

Tiering Benefits
1. Reduce the difficulty and complexity of development
2. The corresponding product development can be realized modular
3. There is a standard interface between the layer and the layer
4. Separate layers from each other

1-4 low Floor, 5-7 high
Application Layer Application
Human-Computer interface
Presentation Layer Presentation
1. The corresponding format of data from the high-level is reflected.
2. Compression and encryption
Session Layer Sessions
To logically differentiate a communication session
Transport Layer Transport
1. End-to-end communication
2. Flow control, data correction (via retransmission).
Networking Layer Network
1. To find the best path for data forwarding
2. Define the logical address (software address).
Data Link Layer
1. Define the access mode of the transfer media, define the hardware address
2. is responsible for the physical layer of the bit bit group synthesis bytes byte, the final framing frame
3. Data error check and flow control buffer can be implemented to adjust the sender's data accordingly
Physical Layer Physical
Defines the level and voltage standard of data transmitted on a material medium.

Packaging
When the data is processed from the upper level to the lower level, the process of the header information and the tail control information is added at each level.
Solution Encapsulation
Contrary to encapsulation

OSI Reference Model