osi seven-layer model
The application layer provides the interface
, the binary conversion of the presentation layer machine language, the
dialog layer decides whether to transmit , the
transport layer determines the unreliable error control flow , the
network layer provides the logical address routing, the
data link layer mac error detection, the bit stream transmission between the
physical layer devices
![](https://images2018.cnblogs.com/blog/1289932/201804/1289932-20180430111334262-1384845572.png)