Presentation on computer science on the topic "Combining computers into a local computer network. Organizing the work of users in local computer networks
Teacher: Maybe someone is already familiar with the concept of computer networks? If yes, how can you explain it?
Students: Maybe it's connecting computers.
Teacher: Absolutely correct. So toA computer network is a system of computers connected by information transmission channels.Let's look at the screen and write down this definition in our notebook.
What do you think, what is a computer network for?
Students: To make it easier to work.
Teacher: That's right. However, nThe purpose of all computer networks can be expressed in two words: sharing or sharing. First of all, we mean shared access to data. People working on the same project must constantly use data created by colleagues. Thanks to the network, these and many other problems are solved.
One of the simplest types of connection is pdirect connection of computers.
We know that to interact with external devices, computers have special devices - communication ports. With their help, you can not only connect a computer with a printer, or, for example, a scanner, but also connect two computers with each other - then they can exchange files.Then the simplest computer network is formed, which is called a direct connection.
But a direct connection has three significant disadvantages:
- it allows you to connect no more than 2 computers
- bandwidth is low
- the length of the direct connection is extremely small (up to 1.5 m for a parallel connection and up to 10 m for a serial connection)
To create more complex connections, network adapters are used. If a network adapter is installed on a computer, a so-called network port is formed on it. By connecting the network ports of different computers to each other using cables, computer networks are created.
Types of computer networks.
Based on geographic principles, a distinction is made between local and global networks.Local networks connect computers located a short distance from each other. Global networks can cover vast territories comparable to the size of a state.
Local networks, their basic properties.
These networks are small in scale and operate within one room, building, or enterprise. They are united by relatively few a large number of computers (up to 1000 pieces).
Typically, computers on the same local network are separated from each other at a distance of no more than one kilometer.
Using a local network meets two main goals:
- Sharing files between network users
- Use of publicly available resources: large disk space, printers, programs, etc.
Basic properties:
- High transmission speed, large throughput;
- Low transmission error rate;
- A precisely defined number of computers connected to the network;
- Has one or more interconnected control centers.
The last parameter essentially determines that this is a local network. For example, HP has one of the largest local networks, with computers distributed throughout the world. The main difference between such a network and a global one is the presence of a single control center, which is fundamentally absent in global networks.
Organization of drugs.
From the point of view of organizing the interaction of individual elements in drugs, there are two types:
1. Peer-to-peer network
All connected computers have equal rights. The user can have access to the resources of all computers connected to him. No special software needed. Peer-to-peer networks are supported by Windows95/98/00.
2. Network with a dedicated file server (host computer).
It is also called a client-server network.. There is one central machine, which is called a server, and many computers connected to it - workstations or clients. The central machine is usually a more powerful machine (has a large disk memory, a printer, scanner, modem, etc. are connected to it. Direct exchange of information occurs between the server and the workstation. Of course, in such a system, students can also exchange files, but in transit through server.
The name "server" comes from the English. and is translated as a serving device.The server plays the role of a collective file storage.
The operation of such a network is controlled by the network operating system. Its main purpose is to enable users to work in the LAN without interfering with each other. The most common operating systems for networks with a dedicated server are NOVELL NETWARE, WINDOWS NT.
Topology.
RING: Each computer is connected to each other. The signal carrying information goes in a circle.
BUS: Computers are connected in series. All computers are connected to one cable. The main disadvantage is that a cable break at any point breaks the network.
STAR: Uses a separate cable for each computer, routed from a central device (hub, HUB). More resistant to various cable damages.
SNOWFLAKE: A variety of “Stars”. There is one central server for the entire network and several file servers for different workgroups.
Network hardware.
To organize communication, computers were initially connected with a coaxial cable. However, recently twisted pair cables have become popular, used for laying telephone lines. As the cost decreases, fiber optic cable is also becoming widespread. Along with this, there are cableless network solutions that use radio waves, infrared radiation, etc.
The main parameters of communication lines are throughput (maximum information transfer speed), noise immunity, and cost. Let's write down the relative characteristics of communication lines (see Appendix 1).
Let's try to put our knowledge into practice. What kind of network do we have in our classroom?
Students: Local.
Teacher: That's right. And why?
Students: Because we can transfer information from one computer to any other and are located within the same building.
Teacher: What type of network: peer-to-peer or with a dedicated server, will we classify our network?
Students: Peer to peer! With a dedicated server!
Teacher: So, opinions are divided. How to determine this? Remember we had lessons when the “main machine” was not even turned on, and you were working on your computers. Could this happen if this machine was a server? Of course not. So this is a peer-to-peer network. Topology?
Students: Star.
Teacher: How did you identify it so quickly and correctly?
Students: Because there is a HUB. (the teacher previously, when explaining about the HUB, showed them it with an example)
Teacher: That's right.
Teacher : I propose to organize 4 groups to complete the following task. Each group will describe its option for building a network in a new computer lab, conduct an approximate cost calculation, and justify the advantages and disadvantages of its option.
So, today we learned what computer networks are and what they are needed for, there are two main types of them. We learned more about local networks, their organizations and topologies. In addition, we learned to apply our knowledge in practice.
Your homework will be to know the material in this lesson. In the next lesson I will ask you, and then we will continue to study this topic, we will find out how global networks are organized.
And now the lesson is over. Goodbye! You can be free.
Description of the presentation by individual slides:
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Topic: Connecting computers into a local computer network. Organization of user work in local computer networks. Compiled by: teacher of SMT of the Federal State Budgetary Educational Institution of Higher Education "Kerch State Marine Technological University" Sharatova Natalya Vladimirovna
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A computer network is a collection of computers connected to each other using special equipment, ensuring the exchange of information between computers of a given group and equipped with special communication software.
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Networks provide users with the opportunity not only to quickly exchange information, but also to collaborate on printers and other peripheral devices, and even to process documents simultaneously.
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The main characteristics of networks include: Bandwidth – the maximum amount of data transmitted by the network per unit of time. Bandwidth is measured in Mbit/s. Network response time is the time spent by software and network devices to prepare for transmitting information over a given channel. Network response time is measured in milliseconds.
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Computers can communicate with each other because there are sets of rules, or protocols, that help computers understand each other. Protocols are necessary to ensure that the communication process occurs without errors. Protocols help define how information is sent and how it is received. A network protocol is a set of rules for organizing work on a computer network.
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Local network (LAN - Local Area Network) - a network within an enterprise, institution, or one organization. Regional network (MAN - Metropolitan Area Network) - a network within a city or region. Wide Area Network (WAN) is a network on the territory of a state or group of states.
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Workstation (client-machine, workplace, subscriber station, terminal) is a computer at which a computer network subscriber directly works. A network of workstations is represented by a set of workstations and communication means that ensure interaction of workstations with the server and with each other.
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A server is a computer that performs common computer network tasks and provides services to workstations. A server network is a collection of servers and communications that connect servers to the underlying data network.
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The core data network is a set of means for transmitting data between servers. It consists of communication channels and communication nodes.
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A communication center is a set of switching and data transmission facilities at one point. The communication node receives data arriving through communication channels and transmits data to channels leading to subscribers.
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A local network is a system of interconnected computers operating within the same room, building, or organization. Local computer networks
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rapid exchange of information sharing of peripheral devices (printer, scanner, modem, etc.) simultaneous work with documents Based on the distribution of functions, local computer networks are divided into peer-to-peer and multi-peer
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In a peer-to-peer network, all computers have equal rights. Peer-to-peer networks are also called workgroups. A work group is a small team, so peer-to-peer networks most often have no more than 10 computers. Types of local networks A dedicated server is a server that functions only as a server (excluding client or workstation functions). Peer-to-peer network Dedicated server network
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peer-to-peer server-based Computers have equal rights. Users independently decide which computer resources to make publicly available. A computer used as a repository of general information resources and allowing connection to public technical devices. The local network
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Peer-to-peer network Computers in such a network have equal rights in relation to each other. Each user on the network decides for himself which resources of his computer he will provide for public use. The computer acts both as a client and as a server.
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Server (from the English server - service device) is a computer that distributes resources between network users, used as a repository of shared information resources and allowing connection to public technical devices.
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The server can provide various services, of which the most well-known are the following: storage and provision of files (file server); output to a printer (print server); receiving and forwarding fax messages (fax server); receiving, storing and transmitting messages Email(mail server); website hosting (web server).
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“Bus” topology A single cable is used along which all computers on the network are connected. A terminator is needed to absorb the transmitted signal at the ends. Simplicity If one computer fails, this will not affect the operation of the others. At any given time, only one computer can transmit data. A cable break leads to the termination of the network. If there are a large number of computers, the network works slowly terminator terminator
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Tire. The communication channel connecting nodes into a network forms a broken line - a bus. Any node can receive information at any time, and transmit only when the bus is free. Data (signals) are transmitted by the computer to the bus. Each computer checks them, determining who the information is addressed to, and accepts the data if it is sent to it, or ignores it. If computers are located close to each other, then organizing a network with a bus topology is inexpensive and simple - you just need to lay a cable from one computer to another. Signal attenuation with increasing distance limits the length of the bus and, therefore, the number of computers connected to it. Bus topology problems arise when a break occurs (contact failure) anywhere in the country; the network adapter of one of the computers fails and begins to transmit signals with noise to the bus; you need to connect a new computer.
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Ring topology Signals are transmitted along the ring in one direction and pass through each computer (closed network). The cable has no free end and therefore does not need a terminator. Each computer amplifies the signals and transmits them to the next computer. When one computer fails, the entire network stops functioning.
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Ring. The nodes are connected into a closed curve network. Data transfer is carried out in one direction only. Each node, among other things, implements the functions of a repeater. He receives and transmits messages, and perceives only those addressed to him. Using a ring topology, you can connect a large number of nodes to the network, solving the problems of interference and signal attenuation using the network card of each node. Disadvantages of a ring organization: a break at any point in the ring stops the operation of the entire network; the time of message transmission is determined by the time of sequential operation of each node located between the sender and recipient of the message; Due to the flow of data through each node, there is a possibility of unintentional distortion of information.
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“Star” topology Server Network management is centralized (there is a special central device (hub), from which “rays” go to each computer, i.e. each computer is connected to its own cable). If one computer fails, the network remains operational. For large networks, cable consumption increases significantly. If a server fails, the network stops functioning.
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Star. The network nodes are connected to the center by rays. All information is transmitted through the center, making it relatively easy to troubleshoot and add new nodes without interrupting the network. However, the cost of organizing communication channels here is usually higher than for a bus and ring.
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Tree topology A hierarchical connection of nodes emanating from a common root node. There is only one route between any two nodes. high efficiency of use; failure of one station or cable will not affect the operation of others; saving working time. requires a large amount of cable; Reliability and performance are determined by the central node.
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The combination of basic topologies - hybrid topology - provides a wide range of solutions that accumulate the advantages and disadvantages of the basic ones. In addition to the problems of creating local computer networks, there is also the problem of expanding (merging) computer networks. The fact is that a computer network created at a certain stage of development of an information system may, over time, cease to satisfy the needs of all users. In the same time physical properties signal, data transmission channels and design features of network components impose strict restrictions on the number of nodes and geometric dimensions of the network.
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Network hardware To organize a local network, you need to install a network card in each PC and connect all computers using a special cable.
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A network adapter is a device necessary to connect a computer to a local network. Each network adapter has a unique internal number, the so-called MAC address, which allows you to uniquely identify the source of information in the network environment.
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Network cards are characterized by: Bit capacity: 8 bits, 16 bits and 32 bits. The data bus through which information is exchanged between the motherboard and the network card: ISA, EISA, VL-Bus, PCI, etc. The controller chip on which this board is made. Supported network transmission medium. Operating speed: Ethernet 10Mbit and/or Fast Ethernet 100Mbit, Gigabit Ethernet 1000Base-T. MAC address
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The network adapter is connected to the cable using special connectors, the type of which depends on the type of cable. For example, for a twisted pair cable, an RG-45 type connector is used, which looks like a telephone connector. There are network adapters that use the wireless principle of interaction. Currently, the three main types of wireless data transmission are radio communication, microwave communication and infrared communication. Currently, the most common option for organizing a wireless local network is the use of WiFi equipment.
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Each network adapter has a unique internal number, the so-called MAC address, which allows you to uniquely identify the source of information in the network environment.
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Computer network hardware Transmission medium Information can be transmitted using physical signals of various natures. These can be electrical signals, electromagnetic radiation, optical signals. Depending on the type of signal, different transmission media are used - wired or wireless. The transmission medium is a physical environment in which it is possible to transmit information signals in the form of electrical, light and other impulses.
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Wireless environment Wired environment In wired environments, computers and other network devices are connected by cables, such as copper (twisted pair, coaxial cable) or fiber optics. Data is transmitted in the form of electrical or optical signals. TV and radio broadcast satellite communications
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Coaxial cable - transmission speed up to 10 Mbit/s Twisted pair - transmission speed up to 100 Mbit/s Types of cables Fiber optic cable - transmitting information over long distances
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Network cables Twisted pair is one of the components of modern structured cabling systems. Used in telecommunications and computer networks as a physical signal transmission medium in many technologies such as Ethernet, Arcnet and Token ring. Currently, due to its low cost and ease of installation, it is the most common solution for building wired (cable) local networks.
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The simplest design of a coaxial cable includes a copper core enclosed in insulation, a metal braided shield and outer shell. In some modifications there is an additional layer of foil, which means double screening. The strongest interference is overcome by cables containing four shieldings, including two layers of foil and two layers of metal braid. Network cables
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Fiber optic cable. In a fiber optic cable, digital data is distributed by optical fibers in the form of modulated light pulses. This is a relatively secure transmission method because it does not use electrical signals. So, it is impossible to connect to a fiber optic cable without destroying it and intercept data, which is not the case with any cable that conducts electrical signals. Fiber optic lines are designed to transmit large amounts of data at very high speeds, since the signal in them is practically not attenuated or distorted. Optical fiber is an extremely thin glass cylinder called the core. It is covered with a layer of glass (cladding) with a different refractive index than the core. Sometimes the optical fiber is made of plastic. Plastic is easier to install, but it transmits light pulses over shorter distances compared to glass optical fiber. Each optical fiber transmits signals in only one direction, so the cable consists of two fibers with independent connectors. One of them is used for transmitting, and the other is for receiving. The cable's rigidity is increased by a plastic coating, and its strength is increased by Kevlar fibers. Network cables
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Transmission Media Wireless Media Characteristics of Transmission Media In wireless media, cables are not used and data is transmitted over the air, usually in the form of radio signals. One of the main characteristics of the transmission medium is the data transfer rate, which is measured in: bits per second (bps), kilobits per second (Kbps), megabits per second (Mbps) and gigabits per second (Gbps) . The data transfer rate in computer networks is defined as the number of binary bits transmitted through a certain medium per unit of time.
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Wireless connection Uses airborne radio; this is convenient because no wiring is required, but it is more expensive than wired connections Wireless connection
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Network interfaces In order for a computer or other device to be connected to a local network, it must be equipped with a network interface (network card) to which a network cable is connected or which will provide communication via a radio channel. Network interfaces are manufactured in the form of boards. A network interface is equipment designed to connect a computer or other device on a local network
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Modems A modem is a device used to connect computers to global networks. To connect individual computers and local networks to the worldwide global network, the Internet can be used telephone communication, cable television networks, as well as satellite mobile communications. The parameters of the signals transmitted by these communication channels and the signals used in local networks and in the computer itself are different. Therefore, to connect to the global network, a special device – a modem – is required. Depending on the communication channel for which the modem is assigned, modems for telephone lines, television cable lines, satellite modems, and modems for mobile communications are distinguished. Modems are available as separate devices and as cards that are inserted into slots on the motherboard.
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* Modems analog signals digital codes digital codes 101001101 A modem is a device for connecting two computers using a telephone line. Modem (modulator/demodulator) is a device for converting an analog signal into a digital code and vice versa. Exchange rate (bits per second): reception up to 56 Kbit/s transmission up to 33 Kbit/s 101001101 modem modem
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Modems Modem CMOTECH Wireless high-speed modem One of the first USB modems for using mobile Internet.
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Modems Satellite modem Thrane Thrane Explorer 700 Modems for television cable lines
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Modems Modems for mobile phone calls Modems for telephone lines
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A simple local area network (LAN - Local Area Network) with Internet access consists of network adapters(installed in computers) that are connected to a hub or switch, which in turn is connected to a router. Currently, to build LAN networks in the office or at home, in the vast majority of cases, Ethernet technology is used, and the network cable is twisted pair.
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Hubs, switches and wireless access points To implement a star network topology, you need a device to which all computers on the network will connect and which will ensure the exchange of data between them. The function of such “central” devices can be performed by hubs and switches. A hub is a device that transmits received data to all devices connected to it. A switch is a device that determines who exactly the received data is addressed to, and therefore does not forward it to all devices, but only to the recipient. To create wireless networks, wireless access points are used, which function in the same way as hubs.
Local network Local network A local network unites computers installed in one room (classroom, office, etc.), in one building or in several nearby buildings. Typically, local network computers are located at a distance of no more than one kilometer. As the distance increases, special equipment is used.
Server Server (from the English server - service device) is a computer that distributes resources between network users. The server has a powerful processor, large RAM and disk memory, and stores the bulk of software and network data that can be used by all network users.
In networks with a dedicated server, client-server technology is implemented. Server software is installed on the server: server operating system; WEB server (Intranet organization); proxy server (ensuring work with Internet workstations); file server (providing file sharing), etc. Dedicated server network software
The most common ways to connect computers are: bus (usually used for peer-to-peer networks); star (used for any local networks); ring. Network hardware (Computer network topology) LAN topology –. LAN topology is the physical arrangement of network computers relative to each other and the way they are connected by lines.
To organize a local network you must: determine the name of the Working Group; assign each computer a unique name and IP address in this Workgroup, and also set a subnet mask address (in some cases, an explicit IP address and subnet mask address may not be set).
Local resource. Network users are prohibited from accessing computer resources. To ensure the availability of local resources, you need to set the switch to the Shared resource position. Shared resource. Allows the use of computer resources (disk memory and peripheral devices - printer, modem) to network users. To do this, you need to allow Sharing the folder. In this case, it is necessary to determine the access level. Modes of access to network resources
Read only Allows network users to open or copy files and folders. Full access Allows network users to perform all operations on files and folders (move, delete, edit, rename, etc.). Password Access This mode gives different categories of users different access rights, such as read-only or full access.
Connecting computers into a local network
The local network — the combination of several computers located at a short distance from each other (usually within the same building) to jointly solve information, computing, educational and other problems. A small local network may have 10-20 computers, a very large one may have about 1000.
Purpose local networks
· sharing common hardware (printer drives, modems)
· operational data exchange
· information system of the enterprise (institution)
Organization local networks.
Even though there are many in various ways connect computers together, there are essentially two types of computer networks: peer-to-peer networks and client-server networks.
Peer-to-peer network is an association of equal computers. Typically, a peer-to-peer network unites no more than 10 computers and is organized in homes or small offices.
Client-server network more common in organizations such as a school, business, or library rather than in the home. In this type of network, one computer, called a server, is the heart of the network. It stores information and resources and makes them available to other computers on the same network. The remaining computers using the network to obtain this information are called clients.
Client-server networks are the best option for connecting more than ten computers into a network. They are more expensive, but in cases where it is necessary to store a large amount of information, this is the best choice.
Models of various network configurations
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Topologies local networks
Local networks, depending on their purpose and technical specifications, can have different configurations. The general scheme of connecting computers on a local network is called network topology. Network topologies can be different. Most often, local networks can have a “bus” and “star” topology. In the first case, all computers are connected to one common cable (bus), in the second, there is a special central device (hub), from which “rays” go to each computer, i.e. Each computer is connected to its own cable.
IN tire topology, computers are connected to a common channel (bus), through which they can exchange messages.
The bus type structure is simpler and more economical, since it does not require an additional device and consumes less cable. But it is very sensitive to cable system faults. If the cable is damaged in even one place, then problems arise for the entire network. The location of the fault is difficult to locate.
IN radial topology (star topology), in the center there is a hub that sequentially communicates with subscribers and connects them with each other.
In this sense, the “star” is more stable. A damaged cable is a problem for one specific computer; it does not affect the operation of the network as a whole. No troubleshooting required
IN annular topology, information is transmitted over a closed channel. Each subscriber is directly connected to the two closest ones, although in principle it is capable of contacting any subscriber in the network.
In a network with a “ring” type structure, information is transmitted between stations along the ring with re-reception in each network controller. Reception is carried out through buffer drives made on the basis of random access memory devices, so if one network controller fails, the operation of the entire ring may be disrupted. The advantage of the ring structure is the ease of implementation of devices, and the disadvantage is low reliability.
Hybrid A topology is a combination of different topologies in one network. For example, you can connect several star bus networks with a single cable.
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Equipment local network
How do computers communicate with each other?
The operation of the network is based on the fact that all pieces of equipment are connected to each other in one way or another. Each computer and equipment such as printers, scanners, laptops are connected using different cable sizes, satellite communications or telephone lines. Today there are even wireless networks that connect computers using radio waves.
Local network equipment in general case includes:
· computers (servers and workstations);
· network cards (adapters);
· channels of connection;
· special devices that support the functioning of the network (routers, hubs, switches).
Each computer is connected to the network using a network card − adapter.
The network card is connected to the network card cable. If radio or infrared communication is used, no cable is required. In modern local networks, two types of network cables are most often used:
· unshielded twisted pair;
· fiber optic cable.
Typically, the choice of cable for a network depends on the following indicators: installation and maintenance costs, data transmission speed, limitation on the distance of information transmission without additional repeater amplifiers (repeaters), data transmission security.
is a set of eight wires twisted in pairs in such a way as to provide protection against electromagnetic interference.
Twisted pair is the cheapest type of cable. Twisted pair cable allows for a maximum transmission speed of up to 10 Mbit/s. The cable length should not exceed 1000 meters, and the data transfer speed will not exceed 1 Mbit/s. To increase noise immunity, shielded twisted pair is used. Each twisted pair connects only one computer to the network, so a connection failure affects only this computer, which allows you to quickly find and fix problems.
Fiber Optic The cables transmit data in the form of light pulses along glass wires. Fiber optic cables provide the highest transmission speeds; they are more reliable because they are not subject to electromagnetic interference.
Optical cable is very thin and flexible, making it easier to transport than heavier copper cable. The data transfer speed over an optical cable is hundreds of thousands of megabits per second, which is about a thousand times faster than over twisted pair wires.
A fiber optic line is the most expensive type of connection today, but the speed of information dissemination in it reaches several gigabits per second with a permissible distance of up to 50 kilometers. At the same time, communication lines built on the use of optical fiber are practically insensitive to electromagnetic interference.
Where do you plug the cable into your computer? You need an intermediate (interface) device, which is called a network card or network adapter, and in English NIC- Network Interface Controller.
, or NIC, is a built-in device that allows you to connect your computer to a network. Installed on every computer software, which allows it to communicate with other computers.
Wireless communications using radio waves can be used to organize networks within large premises where the use of conventional communication lines is difficult or impractical. In addition, wireless lines can connect remote parts of the local network at distances of up to 25 km (subject to line of sight).
In addition to cables and network adapters, twisted pair LANs use other network devices - hubs, switches and routers.
Hub(also called a hub) is a device that unites several (from 5 to 48) branches of a star-shaped local network and transmits information packets to all branches of the network equally.
(switch) does the same thing, but, unlike a hub, it ensures the transmission of packets to specified branches. This ensures optimization of data flows in the network and increased security against unauthorized penetration.
(router) - a device that transfers data between two networks, including between local and global networks. A router, in fact, is a specialized microcomputer that has its own processor, RAM and ROM, and operating system.
an interface device that connects two different types networks. It receives the information, translates it into the required format, and then forwards the translation to its destination.
Shared external devices include external memory drives connected to the server, printers, plotters and other equipment that becomes accessible from workstations.
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Organization transfers data on the network
A necessary condition for the operation of a unified local network is the use network operating system. Such operating systems ensure the sharing of not only network hardware resources (printers, drives, etc.), but also distributed collective technologies when performing a variety of work. The most widely used network operating systems NovellNetWare,
Linux And Windows.
Computers can communicate with each other because there are sets of rules, or protocols, which help computers understand each other. Protocols are necessary to ensure that the communication process occurs without errors. Protocols help define how information is sent and how it is received.
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_1.jpg" alt=">Combining computers into a local network. Organizing the work of users in local computer networks . Performed:"> Объединение компьютеров в локальную сеть. Организация работы пользователей в локальных компьютерных сетях. Выполнила: Преподаватель ГБОУ СПО «Самарский техникум кулинарного искусства» Иванова Н.Б.!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_2.jpg" alt=">Computer network - connecting computers to exchange information and share resources ( printer, modem,"> Компьютерная сеть – соединение компьютеров для обмена информацией и совместного использования ресурсов (принтер, модем, дисковая память и т.д.).!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_3.jpg" alt=">Local network A local network unites computers installed in the same room (study"> Локальная сеть Локальная сеть объединяет компьютеры установленные в одном помещении (учебный класс, офис и т.п.), в одном здании или в нескольких близко расположенных зданиях. Обычно компьютеры локальной сети расположены на расстоянии не более одного километра. При увеличении расстояния используется специальное оборудование.!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_4.jpg" alt=">Local networks according to the way computers interact are divided into: peer-to-peer; networks"> Локальные сети по способу взаимодействия компьютеров подразделяются на: одноранговые; сети с выделенным сервером.!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_5.jpg" alt=">Client - task, workstation or computer network user. In progress data processing client"> Клиент - задача, рабочая станция или пользователь компьютерной сети. В процессе обработки данных клиент может сформировать запрос на сервер для выполнения сложных процедур, чтения файлов, поиск информации в базе данных и т.д. Сервер, определенный ранее, выполняет запрос, поступивший от клиента. Результаты выполнения запроса передаются клиенту. Сервер обеспечивает хранение данных !} common use, organizes access to this data and transfers the data to the client.
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_6.jpg" alt=">Peer-to-peer local network In a peer-to-peer local network, all computers have equal rights. Shared devices can"> Одноранговая локальная сеть В одноранговой локальной сети все компьютеры равноправны. Общие устройства могут быть подключены к любому компьютеру в сети.!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_7.jpg" alt=">Advantages of peer-to-peer networks: · low cost; · high reliability. Disadvantages peer-to-peer networks:"> Достоинства одноранговых сетей: · низкая стоимость; · высокая надежность. Недостатки одноранговых сетей: · зависимость эффективности работы сети от количества станций; · сложность управления сетью; · сложность обеспечения защиты информации; · трудности обновления и изменения программного обеспечения станций!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_8.jpg" alt=">Network with a dedicated server Network structure with a dedicated server">!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_9.jpg" alt=">Network with a dedicated server Server (from the English server - serving device ) - a computer that distributes"> Сеть с выделенным сервером Сервер (от англ. server - обслуживающее устройство) - компьютер, распределяющий ресурсы между пользователями сети. В сервере установлен мощный процессор, большая оперативная и дисковая память, хранится основная часть программного обеспечения и данных сети, которыми могут воспользоваться все пользователи сети.!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_10.jpg" alt=">Network with a dedicated server Typically workstations"> Сеть с выделенным сервером В качестве рабочих станций обычно используются менее производительные компьютеры с меньшей дисковой и оперативной памятью.!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_11.jpg" alt=">In networks with a dedicated server, client-server technology is implemented. On the server server software is installed:"> В сетях с выделенным сервером реализуется клиент-серверная технология. На сервере устанавливается серверное ПО: серверная операционная система; WEB-сервер (организация Интранет); прокси-сервер (обеспечение работы с Интернет рабочих станций); файл-сервер (обеспечение совместного доступа к файлам) и т.п. ПО сетей с выделенным сервером!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_12.jpg" alt=">Client software is installed on the workstation: operating system for workstations;"> На рабочей станции устанавливается клиентское ПО: операционная система для рабочих станций; клиентская часть прикладного ПО и т.п. ПО сетей с выделенным сервером!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_13.jpg" alt=">The most common ways to connect computers: bus (usually used for peer-to-peer networks);"> Наиболее распространены следующие способы соединения компьютеров: шина (как правило используется для одноранговых сетей); звезда (используется для любых локальных сетей). Аппаратное обеспечение сети!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_14.jpg" alt=">Connection type - “bus” The cable runs from one computer to another , connecting computers and"> Тип соединения - «шина» Кабель проходит от одного компьютера к другому, соединяя компьютеры и периферийные устройства!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_15.jpg" alt=">Connection type - “star” A separate cable from one central node.">!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_16.jpg" alt=">Local network components To organize a local network, you must install in each"> Компоненты локальной сети Для организации локальной сети необходимо установить в каждый ПК сетевую плату и соединить все компьютеры с помощью специального кабеля.!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_17.jpg" alt=">LAN components Sometimes the components necessary for connecting computers are already installed"> Компоненты локальной сети Иногда необходимые для связи компьютеров компоненты уже установлены на системной плате и тогда отдельная сетевая плата не нужна. В этом случае гнездо для сетевого кабеля расположено на задней стенке системного блока.!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_18.jpg" alt=">LAN components Cables Coaxial cable - transmission speed up to 10 Mbit/ pp. Twisted pair"> Компоненты локальной сети Кабели Коаксиальный кабель – скорость передачи до 10 Мбит/с. Витая пара - скорость передачи до 100 Мбит/с.!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_19.jpg" alt=">LAN components Cable connectors for coaxial cable for twisted pair">!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_20.jpg" alt=">LAN components Hubs (HUB or Switch) - serve"> Компоненты локальной сети Концентраторы (HUB или Switch) - служат для соединения компьютеров в сети. Концентратор может иметь различное количество портов подключения (обычно от 8 до 32).!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_21.jpg" alt=">Local network components The overall network connection speed when using a HUB is determined by the speed"> Компоненты локальной сети Общая скорость соединения в сети при использовании HUB определяется скоростью самой медленной сетевой платы. Для Switch скорость соединения любой пары компьютеров определяется скоростью самой медленной сетевой платы в паре (группе).!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_22.jpg" alt=">Network software For working in a local network"> Программное обеспечение сети Для работы в локальной сети необходимо специальное сетевое программное обеспечение. В операционной !} Windows system you already have everything you need to install the network.
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_23.jpg" alt=">Network software To organize a local network you need to: define the name of the Working Group ;"> Программное обеспечение сети Для организации локальной сети необходимо: определить имя Рабочей группы; присвоить каждому компьютеру уникальное в данной Рабочей группе имя и IP-адрес, а также установить адрес маски подсети (в некоторых случаях явный IP-адрес и адрес маски подсети можно не устанавливать).!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_24.jpg" alt=">Network software This window is used to set the computer name and"> Программное обеспечение сети Данное окно используется для установки имени компьютера и Рабочей группы!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_25.jpg" alt=">Network Software These windows are used to set an explicit IP address and subnet mask settings">!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_26.jpg" alt=">This window is used to set the access level to local computer resources"> Данное окно используется для установки уровня доступа к локальным ресурсам компьютера Режимы доступа к ресурсам сети!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_27.jpg" alt=">Local resource. Access to computer resources is prohibited for network users. To ensure availability of local resources"> Локальный ресурс. Запрещается доступ к ресурсам компьютера пользователям сети. Для обеспечения доступности локальных ресурсов нужно установить переключатель в положение Общий ресурс. Общий ресурс. Позволяет использовать ресурсы компьютера (дисковую память и периферийные устройства - принтер, модем) пользователям сети. Для этого, нужно разрешить Открытие общего доступа к папке. При этом требуется определить уровень доступа. Режимы доступа к ресурсам сети!}
Src="https://present5.com/presentacii-2/20171208%5C3432-lokalnaya_set.ppt%5C3432-lokalnaya_set_28.jpg" alt=">Network resource access modes Read only Allows network users to open or copy files"> Режимы доступа к ресурсам сети Только чтение Позволяет пользователям сети открывать или копировать файлы и папки. Полный доступ Позволяет пользователям сети выполнять все операции над файлами, папками (переносить, удалять, редактировать, переименовать и т.п.). Доступ, определяемый паролем Данный режим предоставляет разным категориям пользователей различные права доступа, например, только чтение или полный доступ.!}
