7-layer protocol model 1.OSI
Overview: OSI conceptual framework proposed by the industry, define the hierarchy of open systems, the relationship between levels as a framework for service between the organization and coordination of the layers, but does not provide the OSI reference model that can be achieved the method describes only the concept with respect to the conceptual framework of the OSI, specific criteria should be TCP / IP four-layer architecture reference model
| OSI | name | TCP/IP | effect | unit |
| Seventh floor | Application layer | Application layer | Transmitting and receiving a predetermined fixed message header by header (e.g., message length), the receiver may parse the data message sent by the sender | data |
| Sixth floor | Presentation layer | Application layer | The syntax of the communication problem between different systems, data will be formatted in accordance with the understanding of network solutions | |
| The fifth layer | Session Layer | Application layer | Communication between the packet transceiver automatic, automatic addressing, manage users and application layer | |
| The fourth layer | Transport Layer | Transport Layer | If the data is too large, consider whether to split the data network layer, and finally handed over to the network layer transport | Data segment |
| the third floor | Network layer | Network layer | The network address into a corresponding physical address, also decided to how to find the data received from the sender side to calculate the best route, such as a router | data pack |
| Second floor | data link layer | Link layer | I.e. physical address, the physical layer may occur during the transmission of the transmission is incomplete, this layer defines how to format data, i.e., data as well as provide correct parity, to ensure the transmission reliability | frame |
| level one | Physical Layer | Link layer | In fact, two physical machine communication, the transmission bit stream (i.e., a so-called binary data 0101), such as network cards | Bit |