Detailed explanation and selection principle of LAN communication protocol

The communication protocol is actually a collection of rules and conventions, and the computers we use are inseparable. This article describes three communication protocols in a local area network and the principles for selecting a network communication protocol.

Network communication protocol

Currently, the communication protocols commonly used in LANs are: NetBEUI protocol, IPX/SPX compatible protocol, and TCP/IP protocol.

NetBEUI protocol

1NetBEUI is a small, efficient, and fast communication protocol. In Microsoft's current mainstream products, NetBEUI has become its inherent default protocol in Windows and Windows NT. NetBEUI is designed for a single-segment departmental small LAN consisting of several hundred PCs.

2NetBEUI includes a network interface standard. NetBIOS.NetBIOS is IBM's standard for intercommunication between PCs and is a communication specification used on small LANs. The network consists of PCs with a maximum of 30 users.

IPX/SPX and its compatible protocols

1IPX/SPX is a collection of communication protocols from Novell. The obvious difference with NetBEUI is that IPX/SPX is quite large and highly adaptable in complex environments. Because IPX/SPX considers the problem of multiple network segments from the beginning of design, it has powerful routing function and is suitable for large network use.

2IPX/SPX and its compatible protocols do not require any configuration, it can identify itself by "network 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, and the node ID is the ID 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, the data will be handed over to the network ID in the NetWare server or router, and continue. The next transmission of data. SPX is responsible for error-free processing of the transmitted data throughout the protocol. IPX/SPX is also called "Novell's Protocol Set".

3NWLink communication protocol. Two IPX/SPX compatible protocols are provided in Windows NT: "NWLinkSPX/SPX Compatible Protocol" and "NWLink NetBIOS", both of which are collectively referred to as "NWLink Communication Protocol". The NWLink protocol is Novell's IPX/SPX protocol in the Microsoft network. The implementation, which inherits the advantages of the IPX/SPX protocol, is more suitable for Microsoft's operating system and network environment. Users of Windows NT networks and Windows can use the NWLink protocol to get services for NetWare servers. The NWLink communication protocol is the best choice when moving from a Novell environment to a Microsoft platform, or when two platforms coexist.

TCP/IP protocol

TCP/IP is one of the most commonly used communication protocols, and it is a general protocol in the computer world. In the local area network, TCP/IP first appeared on Unix systems, and now almost all vendors and operating systems support it. At the same time, TCP/IP is also the basic protocol of the Internet.

1TCP/IP is highly flexible, supports any size network, and can connect to almost all servers and workstations. However, its flexibility also brings a lot of inconvenience to its use. No configuration is required when using NetBEUI and IPX/SPX and its compatible protocols, and the TCP/IP protocol is first complicated to use. Each node requires at least one "IP address", one "subnet mask", one "default gateway", and one "hostname". A tool called Dynamic Host Configuration Protocol (DHCP) is provided in Windows NT that automatically assigns clients the information they need to connect to the network, reducing the burden of networking and avoiding errors. Like IPX/SPX and its compatible protocols, TCP/IP is also a routable protocol. The TCP/IP address is hierarchical, which makes it easy to identify and find users on the network, while also increasing the utilization of network bandwidth. Servers running the TCP/IP protocol (such as Windows NT servers) can also be configured as TCP/IP routers when needed. Unlike TCP/IP, IPX in the IPX/SPX protocol uses a broadcast protocol, which often causes broadcast packet congestion, so the best network bandwidth cannot be obtained.

2 TCP/IP protocol in Windows. Windows users can not only use TCP/IP to build peer-to-peer networks, but also easily access other servers. If the Windows workstation only has the TCP/IP protocol installed, it cannot be joined directly to the Windows NT domain. Although the workstation can access the Internet through a proxy server (such as a Proxy Server) running on a Windows NT server, it cannot log in to the domain of the Windows NT server through it. To allow Windows users who only install the TCP/IP protocol to join a Windows NT domain, the NetBEUI protocol must also be installed on Windows.

3 TCP/IP protocol configuration in the LAN. As long as you have some knowledge about TCP/IP, it is very convenient to use.

4IP address. The TCP/IP protocol also uses its own IP address to identify the location and identity on the network. The IP address is also composed of the "network ID" and "node ID" (or HOST ID, host address). A complete IP address consists of 32-bit binary numbers. Each 8-bit (1 byte) is a segment (Segment) with a total of 4 segments (Segment1~Segment4). The segment is separated by a "," Separated. For ease of application, the IP address is not directly used in binary use, but is represented by a familiar decimal number, such as When selecting an IP address, the general principle is that the IP address of each device in the network must be unique, and the same IP address is not allowed on different devices.

5 subnet mask. The subnet mask is used to manage subnets, mainly to extend the "network ID" in the IP address in a multi-segment environment. For example, a node has an IP address of, which is a Class C network. The first three segments of the total of 24 bits are used to represent the "network ID"; the last segment of the total of 8 bits can be freely assigned as the "node ID".

6 gateway. A gateway is a setting used to connect to a heterogeneous network. It acts as a translator and is responsible for translating different communication protocols so that two networks running different protocols can communicate with each other. For Windows NT Live Streaming users running the TCP/IP protocol, users must access the Novell network resources running the IPX/SPX protocol. If you are interconnecting two networks running the TCP/IP protocol, you can do so using the Default Gateway provided by Windows NT.

7 host name. The only IP address in the network that can represent the identity of a user or device. However, in general, many IP addresses are not easy to remember and are not convenient to operate. To improve this situation, we can give each user or device a meaningful name, such as "HAOYUN."

The principle of choosing a network communication protocol

The chosen protocol is to be consistent with the network structure and functionality. 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 better manageability and scalability, such as TCP/IP.

Unless otherwise specified, a network tries to select 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 takes up the memory of the computer, the more protocols you choose, the more memory resources you use on your computer. On the one hand, it affects the speed of the computer, on the other hand, it is not conducive to the management of the network. In fact, a general communication protocol in a network can meet the needs.

Note the version of the agreement. Each protocol has its own development and improvement process, so different versions have appeared, 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.

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.

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