OSI seventh floor

Objective:

Easier to standardize

Reduce relevance: the increase, decrease and update of one layer protocol will not affect the work of other layer protocols, and each layer protocol can develop relatively independently.

Easier to learn and understand

1. Physical layer: photoelectric conversion-0Pax 1 to form data

2. Data link layer: make 0can1 rule data to form meaningful and understandable data

3. Network layer: according to the address information contained in the data, the data transmission from one node to another is realized, which is a global data transmission.

4. Transport layer: TCP, UDP

5. Session layer: correspondence, account password verification

6. Presentation layer: data format conversion, so that the application layer of both sides of the communication can identify the data.

7. System application layer: provide system application interface for user application software