Creating a local network in a computer class. Building networks based on a common bus topology is cheaper, since there are no costs for laying additional lines when connecting a new client. Addressing in local area networks
In recent years, there has been a radical change in the role and place of personal computers and information technologies in the life of society. The modern period of development of society is defined as the stage of informatization. Informatization of society involves the comprehensive and massive introduction of methods and means of collecting, analyzing, processing, transmitting, and archival storage of large volumes of information based on computer technology, as well as a variety of data transmission devices, including telecommunication networks.
The concept of modernization of education, the project “Informatization of the education system” and, finally, technological progress pose the task of forming an ICT - a competent person capable of applying knowledge and skills in practical life for successful socialization in the modern world.
The process of school informatization involves solving the following tasks:
· development of pedagogical technologies for the use of information and communication means at all levels of education;
· use of the Internet for educational purposes;
· creation and use of automation tools for psychological and pedagogical testing, diagnostic methods for monitoring and assessing the level of knowledge of students, their advancement in learning, establishing the level of intellectual potential of the student;
· automation of the school administrative apparatus;
· training in the field of communication and information technologies.
A local network unites computers installed in one room (for example, a school computer lab consisting of 8-12 computers) or in one building (for example, in a school building several dozen computers installed in different subject rooms can be combined into a local network) .
Local Area Network (LAN) is a computer network covering a relatively small area.
In small local networks, all computers usually have equal rights, i.e., users independently decide which resources of their computer (disks, directories, files) to make publicly available over the network. Such networks are called peer-to-peer.
To increase the performance of the local network, as well as to ensure greater reliability when storing information on the network, some computers are specially allocated for storing files or application programs. Such computers are called servers, and a local area network is called a server-based network.
Choosing a school local network structure
A typical school LAN looks like this. There is one Internet access point to which the corresponding router (ADSL or Ethernet) is connected. The router is connected to a switch (switch), to which user PCs are already connected. A DHCP server is almost always activated on the router, which means automatic distribution of IP addresses to all user PCs. Actually, this solution has both its pros and cons. On the one hand, the presence of a DHCP server simplifies the process of creating a network, since there is no need to manually make network settings on user computers. On the other hand, in the absence of a system administrator, a quite typical situation is when no one knows the access password to the router, and the standard password has been changed. It would seem, why do you need to “get into” the router if everything works anyway? That's how it is, but there are unpleasant exceptions. For example, the number of computers at the school increased (another computer science class was equipped) and problems began with IP address conflicts on the network. The fact is that it is not known what range of IP addresses is reserved on the router for distribution by the DHCP server, and it may well turn out that these same IP addresses are simply not enough. If such a problem occurs, then the only way to solve it without going into the settings of the router itself is to manually register all network settings (IP address, subnet mask and gateway IP address) on each PC. Moreover, in order to avoid IP address conflicts, this must be done on each PC. Otherwise, manually assigned IP addresses may fall out of the range reserved for distribution by the DHCP server, which will eventually lead to an IP address conflict.
Another problem is that all computers connected to the switch and, accordingly, having access to the Internet through the router form one peer-to-peer local network, or simply a workgroup. This working group includes not only the computers installed in the school computer lab, but also all other computers available at the school. This includes the director’s computer, the head teacher’s computer, secretaries’ computers, accounting computers (if there is one at the school), and all other computers with Internet access. Of course, it would be wise to divide all these computers into groups and assign appropriate rights to each user group. But, as we have already noted, no domain controller is provided, and therefore it will simply not be possible to implement this. Of course, this problem could be partially solved at the hardware level by organizing several virtual local networks (VLANs) and thereby physically separating student PCs from other computers. However, this requires a managed switch (or at least a Smart switch), the presence of which is very rare in schools. But even if there is such a switch, you still need to be able to configure virtual networks. You can even not use virtual networks, but install an additional router and switch and use different IP addressing (IP addresses from different subnets) for computers in the computer science class and all other computers. But again, this requires additional costs for purchasing the appropriate equipment and experience in setting up routers. Unfortunately, it is impossible to solve the problem of dividing school computers into groups isolated from each other without additional financial costs (the presence of a managed switch in a school is an exception to the rule). At the same time, such a division is not mandatory. If we consider the need for such separation from the point of view of network security, then the problem of protecting the computers of teachers and administration from attacks by students can be solved in another way.
You will need
- - Computers equipped with network cards and connected to each other by a crossover cable;
- - installed fresh drivers for the network card and motherboard chipset.
Instructions
To check the functionality of the network card, launch Device Manager. To do this, select “Control Panel” from the Start menu. Click on the “Hardware and Sound” button → “Device Manager”.
Make sure the network card is installed correctly. Check the "Network Adapters" item in the Manager. There should be no exclamation or question marks near this point. If necessary, reinstall the network card driver.
Install network protocols and services. To do this, open the “Network Connections” folder. Click Start, select Control Panel → Network Connections. In the Network and Internet section, click Network and Sharing Center.
In the “Local Area Connection” column, find “Properties”. In the properties tab, check the default protocols and services installed by Windows. If necessary, configure, install or remove the components suggested in the window.
Set up IP. Go to “Control Panel” → “Network and Sharing Center”. Select the “Local Area Connection” section and click on the “View Status” link. In the window that appears, click the “Properties” button.
From the proposed list of components, select the Internet protocol depending on the OS of your computer. If your OS is WindowsXP, select “Internet Protocol (TCP/IP). For later operating systems - “Internet Protocol version 4 (TCP/IPv4). Then click "Properties".
In the properties window that appears, change the switch from “Obtain an IP address automatically” to “Use the following IP address.” After this, make sure that the “IP Address” and “Subnet Mask” fields are available. Enter IP address values from the range 192.168.0.0/16, 10.0.0.0/8 or 172.16.0.0/12.
If you were given IP addresses in a certain range when you connected your school to the Internet, select addresses from that range. If you need to configure your computer's access to the Internet directly, in addition to the IP address and subnet mask, set the values for the default gateway and DNS servers. These values are given along with the range of IP addresses when connecting to the Internet.
Identify your computer. Right-click on the “My Computer” icon. Select "Properties" from the menu that appears. Open the subsection “Computer name” → “Change”. Enter the name of the computer and workgroup in Latin letters. The workgroup name must be the same for all computers on the network, and the name for each PC must be unique. Click OK.
Video on the topic
Computer networks Local (Local Aria Network, LAN; Ethernet) ~ 100 m Corporate (Local Aria Network, LAN; Ethernet) + equipment ~ several hundred meters Regional (WAN – Wide Area Network (wide, extensive)) MAN – Metropolitan Area Network ( Domolink, Carbina, EUnet/Relcom, Demos/Internet, Sovam Teleport, Global One Russia, GlasNet, Rosnet, RUNNet, etc.) Global (World Wide Web) – Internet (but not quite WWW!), FIDO
What are networks for? To share network resources. Network resources Information (websites, documents, files, ...) Hardware (network modems, scanners, printers, hard drives, network information storage, ....) Division of computers: server and client
One computer is assigned the role of provider of resources (programs, data, etc.), and the other is assigned the role of user of these resources. In this case, the first computer is called a server, and the second is called a client or workstation. You can only work on a client computer running special software. A server is a high-performance computer with a large amount of external memory that provides service to other computers by managing the distribution of expensive shared resources (programs, data and peripheral equipment). Client (otherwise, workstation, workstation, Workstation) is any computer that has access to server services. There are two main types of networks: peer-to-peer and server-based networks.
In a peer-to-peer network, all computers are equal: there is no hierarchy among computers and there is no dedicated server. Typically, each computer functions as both a client and a server; in other words, there is no single computer responsible for administering the entire network. All users independently decide what data on their computer to make publicly available over the network. A dedicated server is a server that functions only as a server (excluding client or workstation functions). They are specifically optimized for quickly processing requests from network clients and for managing file and directory protection. Server-based networks have become an industry standard. There are also combined types of networks that combine the best qualities of peer-to-peer networks and server-based networks. All network software can also be divided into client and server.
Switch Room 24 (11 PCs) switch Room 25 (11 PCs) Teacher25 Teacher24 3rd floor 2nd floor Library PC1 PC2 switch Room 28 (Physics) (1 PC) Room 31 Room 32 Head teacher Room 33 Room 34 Room 35 Room 36 Room. 37 switch Room 39 Room 38 Room 14 Room 13 Room 15 Room 17 Secretary Director 1st floor INTERNET
Ivanov Arkady
Presentation on how to set up a school network
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Completed by: Student of class 10 “A” Ivanov Arkady COMPUTER NETWORK AT SCHOOL
1. The concept of a computer network A computer network is a group of computers interconnected to provide shared access to resources and exchange of information. The hardware component of a computer network also includes communications equipment that allows you to combine individual network segments and organize information flows. Today, a wide variety of communication lines are used to connect computers on a network: all kinds of cables (coaxial, twisted pair), telephone lines, fiber optic lines, radio communications, including satellite communications
Classification of computer networks Computer networks in the most general case can be divided into local and global. Local computer network is a computer network for a limited number of users, connecting computers in one room or within one enterprise. To access the global information space, you need to connect to a global computer network, the most famous of which is the Internet. Internet (Internet) is a worldwide information computer network.
Importance in the modern world A local computer network allows you to effectively organize the exchange of information within a separate organization. Local networks provide their users primarily with services such as shared storage of files for collective work, and sharing of network resources (for example, printers). The Internet can be used in various areas: - professional activities; - commercial activities; - receiving educational services; - rest and entertainment.
2. Structure of the school network topology Any computer network is characterized by topology, protocols, interfaces, network hardware and software. Topology is the way computers are connected in a network. There are many ways to connect network devices, of which there are five basic topologies: bus, ring, star, mesh and mesh. The remaining methods are combinations of the basic ones. In general, such topologies are called mixed or hybrid (here you can follow the hyperlink to the theory, which will be at the end)
Local network diagram at school - user; - Wifi point; -wireless connection (wifi); - modem; - wired connection (twisted pair);
Network setup
1) Set the Ethernet adapter of your computer to a static IP address in the subnet 192.168.1.x (for Windows7 path: Control Panel\Network and Internet\Network Connections, in the local network properties in the properties of Internet Protocol version 4 (TCP/IPv4) use static settings: for example, IP address 192.168.1.100 and subnet mask 255.255.255.0).
2)Launch your Web browser. Enter the default IP address of your device (192.168.1.20) in the address bar. In the field that appears, enter your username and password, as authorized by ubnt/ubnt.
Stage 1: Setting up the base station 1) In the Network tab, set the Network Mode item to Bridge mode 2) In the Management IP Address item, specify DHCP if the settings are issued automatically by the DHCP server. If the settings are static, select Static and enter in the IP Address item the address of our device. In Gateway IP we specify the default gateway. In Primary DNS, the IP address of the DNS server or gateway address.
Go to the WIRELESS tab 1) In the Wireless Mode item, select Acess Point and check the WDS (Wireless Distribution Protocol) box. 2) In the SSID item, enter the wireless network identifier. 3) In the Channel Width item, indicate the channel width (mobile devices only work in the 20 MHz band)
4) In the Security item, select the encryption type and enter the authentication password
Stage 2: Setting up the repeater station 1) In the Network tab, set the Network Mode item to Bridge mode 2) In the Management IP Address item, specify DHCP if the settings are issued automatically by the DHCP server. If the settings are static, select Static and enter in the IP Address item the address of our device. In Gateway IP we specify the default gateway. In Primary DNS, the IP address of the DNS server or gateway address. 3) Click change to save the settings.
Go to the WIRELESS tab 1) In the Wireless Mode item, select Ap-Repeater and check the WDS box. In the WDS Peers item, enter the MAC address of the first station
Disadvantages of a school local network and the Internet Lack of your own server. Lack of a server room or at least a laboratory room with a server room together. Poor wireless connection signal due to thick walls. No funds for good network equipment
Scheme of a possible future local network 2nd floor - Access point (router); -Wired connection (twisted pair); - wireless connection; - Possible server location 2 or 3 floor; - User; - modem (switch);
Development of the project in the future Cameras, good server, FTP server, file sharing service, (electronic textbook)
Setting up a network connection
Point settings How to enter the point settings (type the point’s IP address in the browser address bar)
Setting the IP address of the access point
Setting up network properties (selecting the operating mode of the point (type of signal distribution), selecting mac addresses of connected devices (another point, modem, ...) to this point and a password for connecting to Wi-Fi).
Setting up 2-channel Wi-Fi
Setting a password to enter the point
Using the Ping command line, etc. (3-4 slides with screenshots, maybe a demonstration)
ping PING.EXE is probably the most commonly used command line network utility. It exists in all versions of all operating systems with network support and is a simple and convenient means of querying a host by name or its IP address.
Ipconfig/all The IPCONFIG command is used to display the current TCP/IP protocol settings and to update some of the parameters that are specified during automatic configuration of network interfaces when using the Dynamic Host Configuration Protocol (DHCP).
TRACERT is still the most commonly used network diagnostic tool. The utility allows you to obtain a chain of nodes through which an IP packet addressed to the end node passes. The tracing is based on a method for analyzing responses when sequentially sending ICMP packets to a specified address with the TTL field increasing by 1. Tracert
Netstat Used to display TCP and UDP connections, listening ports, routing table, statistics for various protocols.
Getmac Command The GETMAC command line utility is present in versions of Windows XP and older. Used to obtain network adapter hardware addresses (MAC addresses) on both local and remote computers.
Choosing a provider
Future prospects It will be possible to download 30 films per second from 2020. A group of researchers from the British University of Surrey managed to achieve a record data transfer speed for wireless networks. Working on the 5G communication standard, scientists managed to achieve a speed of 1 Tb/sec, which will allow downloading, for example, 100 movies in 3 seconds. © Kommersant-Online A group of researchers from the British University of Surrey has set a speed record for data transmission over wireless networks. While developing the new generation 5G communication standard, scientists were able to achieve speeds of 1 Tb/sec (or 125 GB/sec). Thus, the previous achievement set by the South Korean manufacturer Samsung in October last year was surpassed. Then the South Korean company improved Wi-Fi technology, which made it possible to transfer data at speeds of up to 575 MB/sec. That is, the current achievement of British developers has made it possible to exceed the maximum speed of Samsung by more than 200 times, and the average data transfer speed in 4G networks by 65 thousand times. READ ALSO Premonition of a quantum leap The commercial launch of 5G networks is predicted for 2020. But scientists at the University of Surrey want to start testing them in public places as early as 2018. The introduction of a new standard will allow, for example, downloading 100 films in 3 seconds. In addition, such data transfer speeds will help significantly reduce time delays when making financial transactions or make it possible to support joint games with high graphic resolution between smartphone users. In addition to the actual data transfer speed, 5G networks will differ from the current ones in operating frequencies, the range of which will be above 6 GHz. In addition, they will use MIMO technology, the essence of which is to use several antennas at once on both the receiving and transmitting sides.
Conclusion Designing a school computer network is a very important task. Here you need to have not only material resources and the availability of the necessary premises for administration, but also knowledge of the administration itself and the ability to design taking into account the given situation. You also need to keep up with the latest developments in network equipment.
Administration Network and server administration is a set of measures to ensure the normal operation of software and hardware components of the local network and server capacity, assist in troubleshooting problems and organize effective network protection from possible threats. Administration tools are software and hardware tools that ensure the implementation of security policies. A system administrator (aka IT administrator) is a specialist who maintains the proper operation of computer hardware and software, and is also responsible for the information security of the organization. Due to the active technologization and computerization of all commercial companies and government agencies, the profession of a system administrator is now in great demand.
Bus topology Bus topology (see Fig. 1.) corresponds to the connection of all network nodes into a peer-to-peer network using a single open-ended cable. The cable must be terminated with a resistive load - so-called terminating resistors. A single cable can only support one channel. In this topology, the cable is called a bus. It is built on the basis of coaxial cable. This topology is advisable to use only in small local networks.
Figure 1. - Example of a bus topology The bus carries a signal from one end of the network to the other, while each workstation checks the address of the message, and if it matches the address of the workstation, it accepts it. If the address does not match, the signal goes further along the line.
Ring topology Ring topology was first implemented in simple peer-to-peer local networks. The general connection diagram resembled a closed ring. Data was transmitted in only one direction. Each workstation acted as a relay, receiving and responding to packets addressed to it and transmitting the remaining packets to the next workstation located “downstream.” The original ring topology of local networks used a peer-to-peer connection between workstations. Because connections of this type were shaped like a ring, they were called closed.
Figure 2. – Ring topology The advantage of local networks of this type is the predictable time for transmitting a packet to the recipient. The more devices connected to the ring, the longer the delay interval. The disadvantage of a ring topology is that if one workstation fails, the entire network stops functioning.
Star topology Star topology local networks connect devices that radiate from a common point. Unlike ring topologies, physical or virtual, each network device is granted the right to independently access the transmission medium. Any device is able to request access to a transmission medium independently of other devices.
Figure 3. – Star topology Star topologies are widely used in modern local networks. The reason for this popularity is its flexibility, expandability, and relatively low deployment cost compared to more complex LAN topologies with strict media access methods.
Figure 4. – Mesh topology Mesh topology is the basic fully connected topology of a computer network, in which each workstation of the network is connected to all other workstations of the same network. It is characterized by high fault tolerance, complexity of configuration and excessive cable consumption. Each computer has many possible ways to connect to other computers. A cable break will not result in loss of connection between two computers.
Lattice topology Lattice is a concept from the theory of computer network organization. This is a topology in which the nodes form a regular multidimensional lattice. In this case, each lattice edge is parallel to its axis and connects two adjacent nodes along this axis. A one-dimensional “lattice” is a chain connecting two external nodes (which have only one neighbor) through a number of internal nodes (which have two neighbors - on the left and on the right). When both external nodes are connected, a ring topology is obtained. Two- and three-dimensional lattices are used in supercomputer architecture.