Computer network Hierarchy Overview _ Networks

OSI layer Seven protocol: Application layer--> Presentation layer--> Session Layer--> Transport Layer--> Network layer--> Data Link Layer--> physical layer

This is slightly more complex, and not practical, but its concept is clear, the architecture theory is more complete.

I personally prefer the following hierarchical structure:

Application Layer--> Transport Layer--> Network layer--> Data Link Layer--> physical layer

Two host communication is actually the application process in two hosts communicating with each other. Although the IP protocol can send the packet to the destination host, the packet still stays at the network layer of the host, but not the application layer.

The TCP segment is transmitted in the End-to-end logical channel abstraction in the transport layer.

Ports are used to flag the process of the application layer.