To talk about the network protocol, first mentioned the open system interconnected reference model (OSI REFERENEC MODEL), that is, the seven-layer framework we usually said, it is the International Organization for Standization, which is proposed in 1977. Standard, also known as ISO / IEC 7498 or X.200. It is worth noting that OSI does not provide a method that can be implemented, it is not a standard, just a conceptual framework that develops standard, is not a network protocol.
OSI is divided into seven layers, its names and functions are as follows:
1. Physical Layer: The main function is to define the physical structure of the network, the transmission of electromagnetic standards, BIT coding and time principles of the network, such as time-repetitive and divided. The network connection type (end-to-end or multi-end connection) and physical topology are determined. Some of the popularity, this layer is primarily responsible for actual signal transmission.
2, according to the Data Link Review: The data link connection is established on both hosts, transmitting the data signal to the physical layer, and processing the signal so as nothing, and reasonable transmission.
3, Network Layer: Mainly responsible for routing, selecting the appropriate path, performing blocking control.
4. Transfer Layer: The most critical layer, providing a reliable end-to-end service to the support, which blocks the underlying data communication details, so that users and applications do not need to consider actual Communication method.
5, session layer: Mainly responsible for communication between two session processes, that is, information exchange between two session layer entities, the exchange of management data.
6. Presentation Layer: Processing a representation of a communication signal, performing translation between different formats, and responsible for encrypted data encryption, compression and recovery of data.
7. Application Layer: Keep the data records required to connect between the application to serve the user. In the work, each layer will give the data from the previous layer to the header, then send it to the lower layer, and then transmitted to the other party by physical media, each layer of the opponent is processed, Remove the information header, and finally restore actual data. In essence, the host's communication is a communication between layers and layers, and is physically transmitted from the upward, and then transmits backward upwards from the lower-by-side host by a physical channel.
In practical applications, the most important thing is the TCP / IP (Transport Control Protocol / Internet Protocol) protocol, which is the most popular commercial agreement, relative to OSI, is current industrial standard or "factual standard", It was made by kahn in 1974. It is divided into four levels: application layer (corresponding to OSI's application layer), transport layer (corresponding to OSI's transport layer), interconnected layer (corresponding to OSI's network layer), host-network layer (with OSI data chain Corresponding to the road floor and physical layer). The TCP / IP protocol is mainly used in the wide area network, and there is also applications in some local area networks, such as use in Windows 9x and NetWare networks, but there is also a gap in terms of functionality and speed. The design goals of TCP / IP are not same. When setting the TCP / IP protocol, there are main IP addresses and subnet masks, gateways (Gateway: Conversion between network protocols in communication, suitable for information exchange between different protocol hosts), domain name resolution server (NDS : Domain name system, that is, converts the URL you entered into digital IP addresses) and NetBIOS, and more. The IPX / SPX (InternetWork Packet Exchange / Sequenced Packet Exchange) protocol is now explained now. This application is a wide range of network protocols. You must have a fast online game in the LAN, you know that this is the credit of IPX / SPX. IPX / SPX is based on Xerox's Xerox's Network System (XNS) protocol, while SPX is based on Xerox's Xerox's SPP (SEQUENCED PACKET Protocol: Sub-Package Protocol) protocol, which is developed by Novell's high-speed protocol to LAN. . It's a significant difference in it and TCP / IP that it does not use the IP address, but the physical address of the NIC, is the (MAC) address. It is also like the TCP / IP protocol to correspond to OSI. Only parts of the transport layer and the network layer are included in the OSI. In actual use, it does not need to set up, it can be used. Since it has played a huge role in the initial in the Internet, many manufacturers have been supported, including Microsoft (but later it has developed their own compatible Novell'ipx / SPX IPX / SPX protocol), etc., now many software and Hardware also supports this protocol.
Compared to the front two routing protocols (routing, it is understood that the selection of two-point path on the network) is in daily applications, and there are two non-routing protocols. They need us to understand, they are: NetBIOS (Network Basic Input / OutputSystem) And NetBEUI (NetBIOS Extended User Interface). NetBIOS is developed by Microsoft and IBM, which is a context-like protocol that establishes a connection session that allows applications on different computers through network transmission. It is designed to design with other computational opportunities to be computational opportunities in the same network. In Win9X & Me, when you select "I hope to enable NetBIOS" in IPX / SPX, you can select "Enable NetBIOS" through TCP / IP. " NetBeui is an IBM designed for its own network product as a network transmission station. It is an expansion version of NetBIOS that defines a low-sized single-network single-wire online. It can be installed directly in Win9X & ME. In some online games, these two protocols may be needed. If you encounter can't play, you can try it two, maybe you can solve your urgent needs. More describe the current application's most widely used network protocol, and the rest of course there are still many other protocols, such as DNA, SNA, AppleTalk, etc. They are also very complicated. But for the entry of netizens, you can master the above agreements that you can initially understand what is the network protocol and its working principle, so that your work is more efficient, and make a foundation for in-depth learning. I hope that my article can play the role of tiles, help everyone. Help everyone.
