Whether it's a few machines, Windows 95/98 peers, or larger Windows NT, Novell, or UNIX / Xenix LAN, people who have worked or manage networks have encountered how to choose and configure network communications. Problem of the agreement. Since many users are not very clear about protocols and their features in the network, communication protocols that do not meet their own network features are often used in the network. As a result, the network cannot be turned on, or the speed is too slow, the work is unstable, affects the reliability of the network. In fact, different network protocols have their own necessary, and each protocol has its main dependent operating system and working environment. Running a good communication protocol on a network, which may not be suitable at another network that looks similar. Therefore, the choice of communication protocol when forming the network is particularly important. Based on the local area network environment, this paper is dominated by Windows NT, while taking into account NetWare, Windows 95/98 and other operating systems, introduces and analyzes the characteristics, performance, and necessary configuration methods of common communication protocols, for groups and network management references.
A, communication protocol
When a network is set, a network communication protocol must be selected such that users can communicate with each other. Protocol is a set of rules for communicating network equipment, which can be understood as a public language that can understand each other. About the protocol in the network can be summarized as two categories: "Internal Agreement" and "External Agreement" (the author is distinguished in this professional classification, but it is indeed solved some confusion in concepts and applications), below Introduce.
Internal protocol
In 1978, the International Standardization Organization (ISO) developed a standard model for network communication, called OSI / RM (Open System Interconnect / Reference Model, open system interconnection reference model) architecture. This structure is divided into seven layers, from low to high, physical layer, data link layer, network layer, transport layer, session layer, representation layer, and application layer. Among them, there is a specific protocol form in any of the upper and lower layers of the network device, and the same level there is also a protocol agreement between the two devices (such as workstations and servers). Here, we define all the protocols between the upper and lower layers and the same level as "internal protocol." Internal protocols are generally rarely involved in the network, it is mainly provided to network developers. If you just have to form a network, you will not pay the internal agreement.
2. External agreement
The external agreement must be selected by our network. Because it is directly responsible for the mutual communication between the computers, it is often referred to as a network communication protocol. Since the introduction of the network, many companies have invested in the development of communication protocol, such as IBM, Banyan, Novell, Microsoft, etc. The agreement developed by each company is initially generally to meet its own network communication, but with the popularity of network applications, interconnection between different networks is increasingly urgent, so the communication protocol becomes the key to addressing the interconnection between the network. technology. Just like using different native language needs a common language to talk, communication between networks also requires a general language, which is a communication protocol. Currently, communication protocols (external protocols) commonly used in LAN have mainly NetBeui, IPX / SPX, and their compatible protocols and TCP / IP.
3. Select the principle of network communication protocol
We generally follow the principles of the following principles when choosing a communication protocol:
First, the selected protocol is consistent with the network structure and function. If you have multiple network segments in your network or when you are connected to the router, you can't use the NetBeui protocol that does not have routing and cross-network segment operations, but you must choose an agreement such as IPX / SPX or TCP / IP. In addition, if your network is small, it is just for simple files and devices sharing. At this time, you are most concerned about the network speed, so you should choose a protocol that takes up memory small and bandwidth utilization when choosing the protocol. NetBeui. When your network is large, and when the network structure is complex, you should choose a good manageability and more expandable protocol, such as TCP / IP. Second, in addition to special cases, a network is as best as possible to select a communication protocol. Many people in reality are to choose multiple protocols, or choose all the protocols provided by the system, in fact, this is very unsuitable. Because each protocol occupies the computer's memory, the more protocols are selected, the more memory resources occupying the computer. On the one hand, affect the computer's running speed, and on the other hand, it is not conducive to the management of the network. In fact, one communication protocol in a network can meet the needs.
Third, pay attention to the version of the agreement. Each protocol has its development and improvement process, and there is a different version, and each version of the protocol has its most suitable network environment. From a whole, the function and performance of the high version protocol is better than the low version. So when choosing, under the premise of meeting the requirements of the network function, you should try to select high versions of communication protocols.
Fourth, the consistency of the agreement. If you want to talk between two computers that implements the interconnect, the communication protocols used by both must be the same. Otherwise, an "translation" is also required to conversion of different protocols, which not only affects communication speed, but also is not conducive to the security and stability of the network.
B, three communication protocols commonly used in the local area network
1. The characteristics of the NetBeui NetBeui Communication Protocol. NetBeui (NetBIOS Extended User Interface, User Extension) is developed by IBM in 1985, which is a communication protocol that is small, high efficiency and fast speed. NetBeui is also a communication protocol for Microsoft's favorite communication, so it is called "Native language" of the communication protocol in Microsoft. Microsoft mainly selects NetBeui as its own communication protocol in its early products, such as DOS, LAN Manager, Windows 3.x and Windows for Workgroup. In Microsoft Today's mainstream products, such as Windows 95/98 and Windows NT, NetBeui has become its inherent default protocol. Some people position Winnt as a low-end network server operating system, which is too directly related to NetBeui with Microsoft's products. NetBeui is designed for a few single-network segment-level small LANs composed of more than 100 PCs, which does not have a function of cross-network segment, namely NetBeui does not have routing functions. If you install multiple network cards on a server, or when you use a router to perform the interconnection of two local area networks, the NetBeui communication protocol will not be used. Otherwise, communication between the devices connected to different network cards (each block connection is connected), and communication between different local area networks will not be possible.
Although NetBeui has many unreasonable places, it also has the advantages of other agreements. In three communication protocols, NetBeui takes a minimum of memory and basically does not require any configuration in the network. Especially in the Microsoft products, almost monopolize the PC operating system, it is very suitable for use in the use of large network beginners.
The relationship between NetBeui and NetBIOS. Careful readers may have discovered that NetBeui contains a network interface standard NetBIOS. NetBIOS (Network Basic Input / Output System, Network Basic Input / Output System) is a standard for IBM in 1983 for implementing PCs to implement PC inter-communication standards. The purpose is to develop a communication specification that is only used on small local area. The network consists of a PC, and the maximum number of users is not more than 30, which is characterized by highlighting a "small" word. Later, IBM found many shortcomings in NetBIOS, so it has been improved in 1985 and launched NetBeui communication protocols. Immediately, Microsoft uses NetBeui as the basic communication protocol of its client / server network system and further expands and improved. The most representative is to add components called SMB (Server Message Blocks, server message blocks) in NetBeui to reduce network traffic clogging. To this end, sometimes the NetBeui protocol is also referred to as "SMB Agreement". People often confuse the NetBIOS and NetBeui. In fact, NetBIOS can only be an interface specification for a network application. It is the foundation of NetBeui, which does not have a strict communication protocol function. NetBeui is a network transport protocol based on NetBIOS.
2. Features of the IPX / SPX Communication Protocol of IPX / SPX and Its Compatibility Protocol. IPX / SPX (InternetWork Packet Exchange / Sequences Packet Exchange, Internet Exchange / Switching) is a Novell's communication protocol set. The obvious difference from NetBeui is that IPX / SPX is large and has strong adaptability in complex environments. Because IPX / SPX considers the problem of multi-network segment at the beginning of the design, with powerful routing features, suitable for large networks. The IPX / SPX and its compatible protocol are the best choice when the user is access to the NetWare server. But in a nonVell network environment, IPX / SPX is generally not used. Especially in the Windows NT network and the peer network consisting of Windows 95/98, IPX / SPX Communication Protocol cannot be directly used.
The IPX / SPX protocol works. IPX / SPX and its compatible protocol do not need any configuration, which can identify your identity through "Network Address". The network address in the Novell network consists of two parts: "Network ID" indicating the physical network segment and "Node ID" indicating special devices. The network ID is concentrated in the NetWare server or router, the node ID is the ID number of each NIC (NIC number). All network IDs and node IDs are a unique "internal IPX address". It is because of the uniqueness of the network address, the IPX / SPX has a strong routing function.
In the IPX / SPX protocol, IPX is the bottom of NetWare, which is only responsible for the movement of data in the network, does not guarantee whether the data is successful, nor does it provide error correction services. When the IPX is responsible for data transmission, if the receiving node is within the same network segment, the data is directly passed to it directly; if the receiving node is remote (not in the same network segment, or in a different local area network), The data will be given to the network ID in the NetWare server or router, and the next transfer of continuing data. The SPX is responsible for non-error handling of the transmitted data throughout the protocol, so we call IPX / SPX also called "Novell's protocol set".
NWLINK Communication Protocol. Two IPX / SPX compatibility protocols are available in Windows NT: "NWLINK SPX / SPX Compatibility Agreement" and "NWLink Netbios" are collectively referred to as "NWLink Communication Protocol". The NWLINK protocol is an implementation of Novell's IPX / SPX protocol in Microsoft Network. It is more adapt to Microsoft's operating systems and network environments while inheriting IPX / SPX protocol. Users of Windows NT Networks and Windows 95/98 can use the NWLink protocol to get the NetWare server service. The NWLINK communication protocol is the best choice if your network turns from the Novell environment to the Microsoft platform, or when you coexist. However, when using the NWLink protocol, "NWLINK IPX / SPX Compatibility Protocol" is similar to the "IPX / SPX Compatibility Protocol" in Windows 95/98, which can only be used as a client's protocol to access the NetWare server access, leaving NetWare servers This compatibility protocol will lose its role; the "NWLink NetBIOS" protocol can not only transfer information between the NetWare server and Windows NT, but also for Windows NT, Windows 95/98 to communicate with each other. 3.TCP / IP protocol
TCP / IP (Transmission Control Protocol / Internet Protocol, Transfer Control Protocol / Internet Protocol) is the most commonly used communication protocol, which is a general agreement in the computer world. In the LAN, TCP / IP appears in the UNIX system, now almost all vendors and operating systems begin to support it. At the same time, TCP / IP is also the foundation protocol of the Internet.
TCP / IP Communication Protocol features. TCP / IP has high flexibility, supports any network, almost all of the servers and workstations. However, its flexibility has also brought many inconveniences for its use, and no configuration is required when using NetBeui and IPX / SPX and its compatible protocol, and the TCP / IP protocol first needs to perform complex settings. Each node requires at least one "IP address", a "subnet mask", a "default gateway" and a "host name". Such complex settings have not brought inconvenience for users of some primary network. However, a tool called Dynamic Host Configuration Protocol (DHCP) is provided in Windows NT, which automatically assigns the information required to connect to the network, reducing the burden on the networking work, and avoids errors. Of course, the features owned by DHCP must have a DHCP server to be implemented.
Like IPX / SPX and its compatible protocol, TCP / IP is also a routed protocol. However, there are some differences in both. The address of the TCP / IP is graded, which makes it easy to determine and find the user on the web, and also improve the utilization of network bandwidth. When needed, the server running the TCP / IP protocol (such as Windows NT Server) can also be configured as a TCP / IP router. Unlike TCP / IP, IPX in the IPX / SPX protocol uses a broadcast protocol, which often occurs blockage blockage, so it is unable to get the best network bandwidth.
TCP / IP protocol in Windows 95/98. Users of Windows 95/98 can not only use TCP / IP to build peer-to-peer networks, but also convenient access to other servers. It is worth noting that if the Windows 95/98 workstation is installed only the TCP / IP protocol, it cannot be added directly to the Windows NT domain. Although the workstation can access the Internet by running on a proxy server (such as Proxy Server) on a Windows NT server, but cannot log in to the domain of the Windows NT server. If you want to install only the TCP / IP protocol to the Windows NT domain, you must also install the NetBeui protocol on Windows 95/98. The configuration of the TCP / IP protocol in the local area network. When mentioning the TCP / IP protocol, there are many users who are troubled by their complex descriptions and configurations, and they don't dare to use it with confidence. In fact, on the LAN users, as long as you have some knowledge about TCP / IP, it is also very convenient to use.
IP address basic knowledge. As you talk about the IPX / SPX protocol, IPX's address consists of "Network ID" and "Node ID" (Node ID), the IPX / SPX protocol is online users on the IPX address. Identification. Similarly, the TCP / IP protocol is also identified by its own IP address, and the IP address is also composed of "network ID" and "node ID" (or Host ID, host address). A complete IP address consists of a 32-bit (bit) binary number, each 8 (1 byte) is a segment, a total of 4 segments (segment1 ~ segment4), and the segment and segments "." Spaced apart. In order to facilitate the application, the IP address does not use binary when practical use, but is expressed as a familiar decimal number, such as 192.168.0.1, etc. The complete composition of the IP address: "Network ID" and "Node ID" are included in the 32-bit binary number. At present, IP addresses are mainly divided into three categories here (in addition to this, there are also two types of adds of D and E. Now these two types of addresses are basically unused, so this article is not involved), and Class A is used Large networks, Class B is used for medium network, Class C is generally used in small networks such as local area networks. Where the first section of the A class address is used to represent the "network ID", and the first bit in the 8-bit binary number of segment1 must be "0". The remaining 3 segments indicate "Node ID"; in the class B address, the first two sections are used to represent the "network ID", and the first two bits in the 8-bit binary number of segment1 must be "10". The latter two segments are used to represent "node ID"; in the Class C address, the first three segments represent "network ID", and the top three in the 8-bit binary number of segment1 must be "110". The last section segment4 is used to indicate "node ID".
It is worth mentioning that all "network ID" in the IP address must be applied to a INTERNIC (Internet Network Information Center, the Internet Information Center), and "node ID" can freely allocate. The IP address currently available is only available in Class C, Class A and Class C. However, when choosing 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. The relevant properties of the "Network ID" in the IP address are listed, and "Node ID" is freely allocated by the user without repeating each other. In fact, classify the IP address, mainly to meet the interconnection of the network. If your network is a closed network, as long as you guarantee the only one of the IP addresses of each device, all of the three types of addresses can be used directly (in case of preventing case, you are still elderly using C Class IP address is good). Subnet mask. The interpretation of the IP address is called the subnet mask. As can be seen from the name, the subnet mask is used to manage the subnet, mainly to extend "network ID" in the IP address in multiple network segment environments. For example, an example is to explain: For example, an IP address of a node is 192.168.0.1, it is a C-class. Among them, the first three sections are used to represent "network ID", which is very precious resources; and the last section of 8 bits can be freely allocated as "node ID". However, if the company's local area network is segmentation, or if the network is interconnected by multiple local area networks, whether you want to assign a "network ID" to each network segment or each local area network? This is obviously unreasonable. At this point, we can use the function of the subnet mask, and all the IP addresses of one or several nodes are used as "network ID" to expand the "network ID" difficult.
When we set an IP address of a node such as 192.168.0.1 to a "network ID", how do other devices on the network know that it is a "network ID", not a node IP address? This will be told by subnet mask. The subnet mask is doing this: if a bit of binary is "1", it knows part of the "network ID"; if it is "0", it is considered to be part of the "Node ID". As will be 192.168.0.1 When "Network ID" is made, the subnet mask is 11111111111.1111111111111111.00000001, the corresponding decimal number is expressed as 255.255.255.1. Otherwise, its subnet mask is 11111111111111111111111111.00000000, the corresponding decimal number should be 255.255.255.0. With a subnet mask, you can easily implement user span sections or cross-network operations. However, in order to allow the subnet mask to work normally, all the devices in the same subnet must support the subnet mask and the subnet mask is the same. Lists the default subnet mask of the three types of networks of A, B, and C.
Gateway. Gateway is a setting to connect to the xenograft. It acts as an translation identity, responsible for translating different communication protocols, making mutual communication between two networks running different protocols. If Windows NT users running TCP / IP protocols To access Novell network resources running the IPX / SPX protocol, they must be used as an intermediary by the gateway. If you interconnect between the two network running TCP / IP protocols, you can use the "default gateway" provided by Windows NT to complete. How to assign the address of the gateway? An example can be answered: If the user of the A network wants to access resources on the B network, you must set a gateway in the network, the address of the gateway should be the "network ID" of the B network (generally understandable as b network server IP address). What should I do when the user of the A network also wants to access the resource of the C network? You only need to add the "network ID" of the C network to the gateway of the A network. Push it in a subkey ... How many IP addresses have you have access to how many networks. CPU name. The only IP address in the network can represent the user or device identity. But in general, numerous IP addresses are not easy to remember, and it is not convenient to operate. In order to improve this situation, we can give each user or device a meaningful name, such as "Wangqun". As for "Wangqun" in the network, how do you know what your corresponding IP address is? This is completely completed by the operating system, and we don't have to consider it.
C, installation, setting, and testing of communication protocol
Some protocols in the LAN are automatically installed when installing the operating system. If you install Windows NT or Windows 95/98, the NetBeui Communication Protocol is automatically installed. When installing NetWare, the IPX / SPX Communication Protocol is automatically installed. In these three protocols, NetBeui and IPX / SPX can be used directly after installation, but TCP / IP is necessary to set it. Therefore, the following is mainly based on the TCP / IP protocol in the Windows NT environment, which introduces its installation, setting, and test methods, and other operating systems are basically the same as Windows NT, even simpler.
Installation of TCP / IP Communication Protocol. In Windows NT, if there is no TCP / IP communication protocol installed, select "Start / Setting / Control Panel / Network", will appear "Network" dialog, select "Protocol / Add" in the dialog, select it TCP / IP protocol, then click the "OK" button. Will you ask if you want to set the "DHCP Server" setting? If your IP address is fixed (usually this), "No" can be selected. Subsequently, the system begins to copy the required files from the installation disc.
Setting of TCP / IP Communication Protocol. In the Network dialog, select the installed TCP / IP protocol to open its Properties. Enter the "IP Address" and "Subnet Masks" in the specified location input. If the user also accesss resources for other Widnows NT networks, you can also enter the address of the gateway at the Default Gateway.
TCP / IP Communication Protocol Test. When the TCP / IP protocol is installed and set, in order to ensure that it is working properly, it must be tested before use. The author recommends that you can use the system's own tools: ping.exe, which can check if any user is connected to other users of the same network segment, whether it is connected to other network segments, and can also check your IP Whether the address conflicts with the IP address of other users. If the server's IP address is 192.168.0.1, if you want to test if your machine is turned on, just switch to the DOS prompt, and type "ping 192.168.0.1". If a response similar to "reply from 192.168.0.1 ...", the TCP / IP protocol works fine; if information similar to "Request Timed Out" is displayed, the setting of the TCP / IP protocol in both parties may be wrong, or There is a problem with other connections (such as NIC, HUB or connection, etc.), and further check. D, small knot
When forming a local area network, specific choice which network communication protocol depends primarily on network size, network management and network management. If you are building a small single network segment network, and there is no need to connect, it is best to choose the NetBeui communication protocol. If you are migrating from NetWare to Windows NT, or when you coexist, IPX / SPX and their compatible protocols provide a good transport environment. If you are planning a high-efficiency, interconnect, and scalable network, TCP / IP will be ideal.
