I. Software knowledge 1. Computer network communication devices and lines will be in different places and spatial locations, and operate relatively independent multiple computers, configure certain systems and application software, soft, in the original independent computer, Hardware resource sharing and information delivery, this system can be called a computer network. 2. Network classification is generally divided into a wide range of area-wide scores (WAN, ie Wide Area Network), regional network (MAN, LAN, Local Area Network), WAN It seems that the domestic straight radiopes, MAN is like only a telephone network that can only call the local call, and the LAN is equivalent to the internal telephone network of a plant. 3. The planning of the LAN, design and construction procedures will be summarized as such a few steps: first select the network topology according to the use of specific environments; then select the network card and transport media; then consider whether other related networked devices, such as hub , Repeater, joint, etc., then make a connection, installation; finally load network operating system software, load application software. 4. Network Topology Structure If the Ethernet has been determined, it is determined that the network structure and communication protocol to use, then consider the specific physical connection between the computer, especially between workstations and servers. That is to consider the Topology structure of the network. There are three types of basic LAN topologies: the first type: Bus or Daisy-chain Topology. The bus type topology is to connect all file servers and workstations with a cable. The network structure is the easiest, the cable is used in the shortest, but the problem is difficult to detect. Second: Star Topology (Star or Star-Wired Tree). All computers are connected to a central point, this center point can be a file server or a hub's hub (HUB). The third: integrated, integration of two ways. The topology of the actual network is often integrated. 5. How to determine that the appropriate network topology is simply summarized: When the number of computer tables is more or the reliability requires high, it is preferred to use a star or tree connection; for a few distances, far or reliability requirements When sharing tasks are not heavy, consider using a cable for bus type connections. By the way, the network is best given to consider connecting various equipment using twisted pair, because it is convenient to install, the price is cheap. 6. There are three common products in the market operating system software, and three of the three types of client / servers are Novell NetWare; second, Microsoft Windows NT; third is all types of variant versions of UNIX. There are two kinds of right networks: Windows95 / 98 and Windows for Workgroups. For small local area networks, for the LAN of the server, new network is preferred to use NT, "old" network transformation with NetWare 4.10 more appropriate, in a small peer network environment, if you just want to share files and resources The cost is low, the maintenance is simple and the safety requirements are not high, and WINDOWS95 / 98 is very suitable. 7. To create a network (such as LAN, what you should do first) should first consider which network architecture is used to build a network. The network architecture refers to the overall design of the computer communication system, which provides standards for network software, hardware and network communication protocols, data access control, and topology.
Three common network communication protocols: TCP / IP, IPX / SPX and NetBIOS, respectively, called transmission control protocols / Internet protocols, Internet information exchange package / sequential information exchange package, network basic input / output, they are some intermediate protocol. Where TCP / IP is often used to contact different local area networks, IPX / SPX is one of the two basic protocols of the Novell network, which is used for data transfer between network servers and workstations. 8. Alignment to the client / server system, if each computer is equally equally, the resources inside the computer are allowed to be called peer to peer lan, referred to as peer to peer. The peer-to-peer approach will cause the computer to be slower than usual, but the peer is very suitable for small, task light LAN, such as small LANs established in a regular office, family, game hall, and student dormitory. If there are more computers connected to the network, more than 10 sets and share resources, you should consider setting up a computer to store and manage resources that require shared, this computer is called a file server, and other computers are called a workstation. The resource of the workstation does not have to share with others. If you want to share a file with someone, you must first copy the file from the workstation to the file server, or install the file on the server at the beginning so that users on other workstations can access these files. This network is called a client / server (Client / Server) LAN. 9.NetWare Network Operating System How to install server installation is this: first load DOS on the C drive, then create a novell directory, then copy all the contents on the NetWare system disk into this directory, then on the hard disk Running Server, enter the server name, IPX internal network number, load disk driver, determine the hard disk control setting, load the network driver and its configuration, load the Install general program, establish a NetWare hard disk partition, establish and install the volume, To copy it into the system and public files, create autoexec.ncf and startup.ncf, and finally turn off the server and restart. There is a simple installation of the disk workstation (referring to his own hard disk or floppy disk), after setting the NIC, run WSGEN, this is a menu driver, generates IPXcom by the network card setting. Then prepare a batch file, first execute IPX, then execute NETX, you can log in to enter the network after using the workstation to communicate with the server. 10.Windows NT operating system installation needs to pay attention to the highest version of Windows NT is 4.0. You can upgrade directly from DOS 6.22, Windows95 / 98, but after the opening, some original applications are reinstalled, otherwise they cannot be used. The specific installation process is very similar to the installation of Windows95. / 98 Multi-start, that is, a pure server NT work environment, select NTFS; 2 After entering the serial number, you need to select per server ... or per customer ... formerly, for a small LAN selection primary domain server with only one server; 3 When you need to select a primary domain server, a backup domain server, or a stand-alone server, only one server's LAN selection primary domain server; 4 The difference between "Line Connect to Network" and "Remote Access Network" is that the latter must use the modem, so LAN Will choose the former.
5 There are three types of protocols "TCP / IP", "NWLINK", "NWLINK", "NETBEUI", "TCP / IP" for the server to connect to the Internet and other non-Soft Networks; "NWLINK" is available to Novell with NetWare The network is connected; "NetBeui" is the NT network must be selected, it is the upgrade version of NetBIOS, and it can be selected by the person. 11. IPX, volume and two NCF file IPX are the basic protocol of NetWare file redirection template. The volume is a logic block that NetWare is divided on the hard disk, and its size and volume name can be defined. NetWare regulations must generate a volume and can have up to 64. The first name is SYS, the capacity is not less than 55m. General small LAN, 2 to 4 user volumes are enough, mainly used to store system and data files to facilitate management and ensure security. AutoExec.ncf and Startup.ncf are equivalent to AutoExec.bat and Config.sys in the DOS system in the server. In NetWare, these two files are essential. The latter is the driver name of the hard disk controller, and the former is the automatic batch file when the server is started. 12. In the NetWare system, the installation of the application software is installed on the Novell Online, you need to build a directory structure before installing. Software commonly used for network users is usually installed on the server so that it is convenient for permission assignment. The application software has its installer, not install is setup, starts them automatically, after installation, enter its installation directory, perform the following sharing instructions. If it is installed on the workstation, it should be copied to the network hard disk, and then enter the directory to perform sharing instructions. 13.NetWare and Windows NT NT systems are mainly a low-end and medium-size application platform. NetWare is a very cost-effective file and directory service network operating system. The network management is very strong, and the new NetWare version is fully convenient. Use NT server resources and support Windows95 / 98 operating systems, and support multiprocessor, the user can log in to the server from any platform to the server. In addition to being uncomfortable, its function is satisfactory. . Both as a mainstream network operating system will also have a considerable period of time. NT requirements for hardware systems are strict than NetWare. Second, hardware knowledge 1. Composition of the hardware one of the LAN is the network server; the other is the network workstation; the third is the network adapter, also called the network interface card or network card; four is the connection line, the "transmission medium", mainly the cable or twisted Line, there is an uncommon optical fiber. We connect these hardware and install software that is specifically used to support network actions, including system software and application software, then a local area network that meets work or life needs. 2. Network server is a file server in a general network server. The file server is the most important hardware device in the network, which is equipped with NOS (network operating system), system management tools, etc., which is the basic configuration necessary to establish a client / server LAN; for peer-to-peer networks, Each computer is both a server and a workstation. In the Novell network, there are other two servers: First, print servers, used to manage and control print tasks in the network, one print server can support 16 printers; second, asynchronous communication servers, mainly used for remote communication And network connection with other asynchronous hosts. These two servers are relatively rare in general LANs.
If there is a conditional purchase special file server, it is better because of the hardware, we don't say that the server's hard disk access speed is very much on the network, so the dedicated server is stored, speed, Reliability has considered, such as hard disk mirroring, duplex, and other fault tolerant techniques generally apply. However, the general small LAN uses the PIT grade microcomputer, which is equipped with a large-capacity hard disk with a number of GBs and a 32-bit network card to meet the requirements. 3. NIC NIC is an inserted microcomputer I / O slot for issuing and receiving different information frames to implement the integrated circuit card for microcomputer communication. It can be divided into ISA network card, EISA network card, PCI network card, etc. according to bus type. The working principle of the NIC is similar to the working principle of the modem, but only the input and output in the NIC is a digital signal, and the transmission speed is much faster than the modem. There are 16 and 32-bit points, and the 16-bit network card representative products are NE2000. It is very popular on the market. Some are not named, generally used for workstations; 32-bit network card representative products are NE3200, generally used There are also compatible products for sale on the server. A network is best to use the same brand whether it is a 16-bit or 32-bit network card to ensure good compatibility. In general, the quality of compatible products can also be, and the impact on small LANs is not obvious. It is currently available to buy plug-and-play type. There are three specifications of the interface of the NIC: the coarse coaxial cable interface (RJ-45 interface); a thin shaft cable interface (BNC interface); no shield twisted pair interface (RJ-45 interface). The average network card only provides an interface, but there are two or even three interfaces. Red, green light is a network card's work indicator. When the red light is on, it means that the data is being sent or received, and the green light is on, and the network connection is normal, otherwise it is not normal. It is worth noting that if the length of the two computer lines is greater than the predetermined length (the twisted pair is 100 meters, the thin shaft cable is 185 meters), even if the connection is normal, the green light will not be bright. 4. Commonly used transmission media commonly used coaxial cables and no shielded twisted pairs for transmission media. Coaxial cable: Model RG-11 (10Base5), using AVI interface, mainly used for Based Dry Backbone. Thousand Tongxia Cables: Model is RG-58 (10Base2), using the BNC interface, mainly used for network connections between computers, but is gradually replaced by twisted pairs due to linked pairs, reliability differences. Twisted pair: twisted pair is also shielded twisted pair (STP) and non-shielded twisted pair (UTP). At present, the commonly used UTP twisted pair is divided into five categories and three types of two specifications. The general small LAN (10M network) uses three types of large LAN (100M network), using RJ- 45 interface. 5. Hub in the computer classroom, the tree network is to select a workstation to connect to the server, and the hub is connected to the server. The hub is also known as HUB, is a special equipment that centrally completed multiple devices, providing error-in-inclusions and network management. HUB has three types: 1 Passive HUB that is not added to the transmitted data, is called a passive hub; 2 can regenerate signals, monitor data communication Active Hub, known as active hub; 3 can provide network management functions Intelligent Hub, known as a smart hub. There is also a special HUB called a repeater that connects two local area networks or extends a local area network.
