Different protocols have their own existence, and each protocol has its own operating system and working environment. A communication protocol that works well on one network may not be suitable at all on a network that looks similar. Therefore, the choice of communication protocol is especially important when building a network.
Whether it is a Windows 95/98 peer-to-peer network of several machines, or a large-scale Windows NT, Novell or Unix/Xenix LAN, anyone who has personally formed or managed a network has encountered how to select and configure network communication. Agreement. Since many users are not very clear about the protocols in the network and their functional characteristics, communication protocols that do not conform to the characteristics of their own networks are often selected in the networking. As a result, the network cannot be connected, or the speed is too slow, the work is unstable, and the reliability of the network. Below I will analyze the characteristics and performance of each protocol to illustrate the position and position of my configuration agreement.
First, the communication protocolWhen building a network, you must choose a network communication protocol so that users can communicate with each other. A protocol is a set of rules that network devices use to communicate. This set of rules can be understood as a common language that can be understood by each other. The protocols in the network can be summarized into two categories: "internal agreement" and "external agreement" are introduced separately below.
1. Internal agreement
In 1978, the International Organization for Standardization (ISO) developed a standard model for network communication called OSI/RM (Open System Interconnect/Reference Model) architecture. The structure is divided into seven layers, from low to high, physical layer, data link layer, network layer, transport layer, session layer, presentation layer and layer. Among them, any network device has its own specific protocol form between the upper and lower layers, and there are also protocol conventions used between the two devices (such as workstations and servers). Here, we define all the agreements between the upper and lower layers and the same layer as "internal protocols." Internal protocols are rarely involved in networking, and are primarily intended for use by web developers. If you are just building a network, you can ignore the internal agreement.
2. External agreement
The external protocol is the protocol that we must choose when we are networking. Since it is directly responsible for mutual communication between machines, it is often referred to as a network communication protocol. Since the advent of the Internet, many companies have invested in the development of communication protocols, such as IBM, Banyan, Novell, and Microsoft. The protocol developed by each company was originally designed to satisfy its own network communication. However, with the popularity of network applications, the requirements for interconnection between different networks are becoming more and more urgent. Therefore, the communication protocol becomes the key to solving the interconnection between networks. technology. Just as people who use different native languages ​​need a common language to talk, communication between networks also requires a common language, which is the communication protocol. The communication protocols (external protocols) commonly used in LANs mainly include NetBEUI, IPX/SPX, and compatible protocols and TCP/IP.
3. Select the principle of network communication protocol
When choosing a communication protocol, we should generally follow the following principles:
First, the selected protocol should be consistent with the network structure and function. If your network has multiple network segments or is connected through a router, you cannot use the NetBEUI protocol without routing and cross-network operation functions, but you must choose protocols such as IPX/SPX or TCP/IP. In addition, if your network is small and only for simple file and device sharing, then your most concern is the network speed, so when choosing a protocol, you should choose a protocol that takes up less memory and high bandwidth utilization, such as NetBEUI. When your network is large and the network structure is complex, you should choose a protocol with good manageability and scalability, such as TCP/IP.
Second, except for special circumstances, one should choose only one communication protocol. In reality, many people do this by selecting multiple protocols at once or by selecting all the protocols provided by the system. In fact, this is not desirable. Because each protocol occupies the machine's memory, the more protocols you choose, the more memory resources you use on your computer. On the one hand, the speed of the computer, on the other hand is not conducive to the management of the network. In fact, a general communication protocol in a network can meet the needs.
Third, pay attention to the version of the agreement. Each protocol has its own and perfection process, so different versions appear, and each version of the protocol has its most suitable network environment. Overall, the functionality and performance of the higher version protocol is better than the lower version. Therefore, in the choice, in the premise of meeting the network function requirements, we should try to choose a higher version of the communication protocol.
Fourth, the consistency of the agreement. If you want to have a conversation between two computers that are connected, they must use the same communication protocol. Otherwise, a "translation" is needed in the middle to convert different protocols, which not only affects the communication speed, but also is not conducive to the security and stable operation of the network.
Second, three communication protocols commonly used in local area networks1.NetBEUI protocol
â– Features of the NetBEUI communication protocol. NetBEUI (NetBIOS Extended User Interface) was developed by IBM in 1985. It is a small, efficient, and fast communication protocol. NetBEUI is also Microsoft's favorite communication protocol, so it is called the "native language" of the communication protocol in all Microsoft products. Microsoft chose NetBEUI as its own communication protocol in its early products such as DOS, LAN Manager, Windows 3.x and Windows for Workgroup. In Microsoft's current mainstream products, such as Windows 95/98 and Windows NT, NetBEUI has become its inherent default protocol. Some people have positioned WinNT as a low-end web server operating system, which is directly related to Microsoft's over-reliance on NetBEUI. NetBEUI is designed for a single-segment departmental small LAN composed of several hundred PCs. It does not have the function of working across network segments, that is, NetBEUI does not have routing function. If you install multiple NICs on one server, or if you want to use a device such as a router to interconnect two LANs, you will not be able to use the NetBEUI communication protocol. Otherwise, communication will not be possible between devices connected to different network cards (one network segment connected to each network card) and between different LANs.
Although NetBEUI has many unsatisfactory places, it also has advantages that other protocols do not have. Among the three communication protocols, NetBEUI occupies the least amount of memory and basically does not require any configuration in the network. Especially in today's Microsoft products almost monopolize the PC operating system, it is very suitable for the majority of network beginners.
â– The relationship between NetBEUI and NetBIOS. Careful readers may have discovered that NetBEUI includes a network interface standard NetBIOS. NetBIOS (Network Basic Input/Output System) is a set of standards developed by IBM in 1983 to implement communication between PCs. The purpose is to develop a communication specification that is only used on small LANs. The network consists of PCs with a maximum of 30 users, which is characterized by a "small" word. Later, IBM discovered many flaws in NetBIOS, so it was improved in 1985 and introduced the NetBEUI communication protocol. Immediately, Microsoft used NetBEUI as the basic communication protocol for its client/server network system and further expanded and improved it. The most representative is the addition of a component called SMB (Server Message Blocks) in NetBEUI to reduce network traffic congestion. To this end, the NetBEUI protocol is sometimes referred to as the "SMB protocol."
People often confuse NetBIOS with NetBEUI. In fact, NetBIOS can only be regarded as an interface specification for network programs. It is the basis of NetBEUI, and it does not have strict communication protocol functions. NetBEUI is a network transmission protocol based on NetBIOS.
2.IPX/SPX and its compatible protocols
â– Features of the IPX/SPX communication protocol. IPX/SPX (Internetwork Packet eXchange/Sequences Packet eXchange) is a set of communication protocols from Novell. The obvious difference with NetBEUI is that IPX/SPX is quite large and has strong adaptability in complex environments. Because IPX/SPX has considered multi-segment at the beginning of the design, it has powerful routing functions and is suitable for large-scale network use. IPX/SPX and its compatible protocols are the best choice when the client accesses the NetWare server. However, in non-Novell network environments, IPX/SPX is generally not used. Especially in Windows NT networks and peer-to-peer networks consisting of Windows 95/98, the IPX/SPX communication protocol cannot be used directly.
How the IPX/SPX protocol works. IPX/SPX and its compatible protocols do not require any configuration, and they can identify themselves by "address". The network address in a Novell network consists of two parts: a "network ID" indicating the physical network segment and a "node ID" indicating the special device. The network ID is centralized in the NetWare server or router. The node ID is the ID number (network card number) of each network card. All network IDs and node IDs are a unique "internal IPX address". It is because of the uniqueness of the network address that IPX/SPX has a strong routing function.
In the IPX/SPX protocol, IPX is the lowest-level protocol of NetWare. It is only responsible for the movement of data in the network. It does not guarantee whether the data is transmitted successfully or provide error correction services. When IPX is responsible for data transmission, if the receiving node is in the same network segment, it will directly transmit data to it according to the ID of the node; if the receiving node is remote (not in the same network segment or in a different local area network), The data will be passed to the network ID in the NetWare server or router to continue the next transfer of data. SPX is responsible for error-free processing of the transmitted data throughout the protocol, so we will also call IPX/SPX "Novell's Protocol Set".
Top Plug,Top Plug In,Standard Power Conversion Plug,Power Conversion Plug
WENZHOU TENGCAI ELECTRIC CO.,LTD , https://www.tengcaielectric.com