Presentation "local network". Presentation "Computer networks
A computer network is a connection of computers to exchange information and share resources (printer, modem, disk memory, etc.).
- A computer network is a connection of computers to exchange information and share resources (printer, modem, disk memory, etc.).
- 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.
- Based on the way computers interact, local networks are divided into:
- peer-to-peer;
- networks with a dedicated server.
- In a peer-to-peer local network, all computers have equal rights. Shared devices can be connected to any computer on the network.
- Network structure with dedicated 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.
- Less powerful computers with less disk and RAM memory are usually used as workstations.
- 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.
- At the workstation
- client software is installed:
- operating system for workstations;
- client part of application software, etc.
- Dedicated server network software
- The most common methods for connecting computers are:
- bus (usually used for peer-to-peer networks);
- star (used for any local networks).
- Network hardware
- The cable runs from one computer to another, connecting computers and peripheral devices
- Each computer is connected to a separate cable from one central node.
- LAN Components
- To organize a local network, you need to install a network card in each PC and connect all computers using a special cable.
- LAN Components
- Sometimes the components necessary for connecting computers are already installed on the motherboard and then a separate network card is not needed.
- In this case, the socket for the network cable is located on the rear wall of the system unit.
- LAN Components
- Coaxial cable – transmission speed up to 10 Mbit/s.
- Twisted pair - transmission speed up to 100 Mbit/s.
- LAN Components
- Cable connectors
- for coaxial cable
- for twisted pair
- LAN Components
- Hubs (HUB or Switch) - used to connect computers on a network.
- A hub can have a varying number of connection ports (usually from 8 to 32).
- LAN Components
- The overall network connection speed when using the HUB is determined by the speed of the slowest network card.
- For Switch, the connection speed of any pair of computers is determined by the speed of the slowest network card in the pair (group).
- Network software
- To work on a local network, you need special network software.
- On Windows operating system
- you already have everything you need to install the network.
- Network software
- To organize a local network you need:
- 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).
- Network software
- This window
- used for installation
- computer name
- and the Working Group
- Network software
- These windows are used to install
- explicit IP address and subnet mask parameters
- This window
- used for installation
- access level
- to local computer resources
- 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
- Modes of access to network resources
- Only reading
- 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, for example, read-only or full access.
Computer networks A computer network is a system for exchanging data between different computers using hardware and software. Network hardware includes: network controllers, modems, hubs, cables. Network software includes: network operating systems.
Purpose of computer networks All computer networks have only one purpose - sharing resources. Resources mean: hardware (computers, network equipment, communication lines) software (programs running on computers) information support (data in files, database records, etc.) .d.)
Types of computer networks All computer networks can be divided into two types: local area networks (LAN) or local computer networks global networks
Local area networks are an association of several computers that allow users to share the resources of computers, as well as peripheral devices connected to the network (printers, disks, modems, etc.)
Main tasks of LAN File separation. LAN allows many users to simultaneously work with one file (document) File transfer. A LAN allows you to quickly copy files of any size from one machine to another without using magnetic storage media (disks, floppy disks, etc.) Separation of application programs. LAN allows different users to share the same copy of Printer Sharing. LAN allows multiple users to share one or more printers. E-mail. The LAN allows you to install a mail service to send messages, reports, and memos to other Intranet users. You can install intranet software on the LAN, which makes it possible to use global Internet technologies when preparing, publishing, indexing and using documents
LAN structure (configuration, architecture, network topology) - a general scheme for connecting computers into a local network. Types of structures: - ring; - radial (star); - tire.
The ring topology provides for the connection of network nodes in a closed curve - a transmission medium cable. The output of one network node is connected to the input of another. Information is transmitted along the ring from node to node. Each intermediate node between the transmitter and the receiver relays the sent message. The receiving node recognizes and receives only messages addressed to it. Ring topology is ideal for networks that occupy a relatively small space. Any type of cable can be used for connection. Consistent discipline in servicing the nodes of such a network reduces its performance, and the failure of one of the nodes violates the integrity of the ring and requires special measures to be taken to preserve the information transmission path.
The bus topology is one of the simplest. It involves the use of coaxial cable as a connection. Data from the transmitting network node is distributed along the bus in both directions. Intermediate nodes do not broadcast forward messages. Information arrives at all nodes, but only the one to which it is addressed receives the message. The service discipline is parallel, which ensures high network performance. The network is easy to expand and configure, and adapt to different systems. A bus topology network is resistant to possible failures of individual nodes, but failure of the bus disrupts the functionality of the entire network. It should be noted that they are short in length and do not allow the use of different types of cable within the same network. This is the simplest and cheapest connection scheme, but it is also the least reliable.
The star topology is based on the concept of a central node (hub), to which peripheral nodes are connected. Each peripheral node has its own separate communication line with the central node. All information is transmitted through a central node, which relays, switches and routes information flows in the network. The star topology greatly simplifies the interaction of network nodes with each other and allows the use of simpler network adapters. At the same time, the performance of a network with a star topology depends entirely on the central node. The advantage is that the central node (hub) can block the transmission of data prohibited by the administrator. Damage to a cable or peripheral computer does not affect the functionality of the entire network. Failure of the central node blocks the operation of the entire network.
Types of local networks Local networks, based on the way computers interact, are divided into: peer-to-peer; networks with a dedicated server.
Peer-to-peer local network In a peer-to-peer local network, all computers have equal rights. Shared devices can be connected to any computer on the network.
Network with a dedicated 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. Less powerful computers with less disk and RAM memory are usually used as workstations.
Network equipment A network card (network card, network adapter, Ethernet adapter) is a peripheral device that allows the computer to interact with other network devices.
Network equipment Sometimes the components necessary for connecting computers are already installed on the system board and then a separate network card is not needed. In this case, the socket for the network cable is located on the rear wall of the system unit.
Network equipment Network hub or Hub (HUB) is a device for combining several devices (computers) into a common network segment. Devices are connected using twisted pair, coaxial cable or optical fiber. A hub can have a varying number of connection ports (usually from 8 to 32).
Network equipment Network switch or Switch is a device designed to connect several computer network nodes within one network segment. Unlike a hub, which distributes traffic from one connected device to all others, a switch transmits data only directly to the recipient.
Network Equipment The overall network connection speed when using the HUB is determined by the speed of the slowest network card. For Switch, the connection speed of any pair of computers is determined by the speed of the slowest network card in the pair (group).
Network equipment A router or router is a network device that makes decisions about sending data packets between different network segments based on information about the network topology and certain rules (connecting different networks into a single whole).
Network equipment Modem (an abbreviation made up of the words modulator-demodulator) is a device used in communication systems and performs the function of modulation and demodulation. A special case of a modem is a widely used peripheral device for a computer that allows it to communicate with another computer equipped with a modem through a telephone network (telephone modem) or a cable network (cable modem).
Characteristics of communication channels Type of communication (types of cables used) Twisted pair of wires Coaxial cable (consists of a central conductor, single-core or stranded, and an external shielding braid) Speed, Mbit/s Distance, meters Noise immunity 10 – 100 90 Low 2 – 44 2000 High
Characteristics of communication channels Type of communication (types of cables used) Telephone line Fiber optic cable (consists of wires, each of which conducts light waves in one direction) Speed, Mbit/s Distance, meters 1 – 2 10 Gbit/s Noise immunity Low 10000 Absolute
Wireless connection To connect laptop computers to a local network, a wireless connection is often used, in which data is transferred using electromagnetic waves. An access point is used as the central network device. Wireless networks such as Wi-Fi can provide data transfer speeds of up to 54 Mbps, but the speed depends on the number of connected computers and their distance from the access point.
Managing data exchange between computers on a network Communication programs manage data exchange between computers on a network. Communication programs: n Client programs - programs that organize requests for data n Server programs - programs that organize the reception, processing and satisfaction of requests Based on the installed software, computers on the network can be divided: n Clients n Servers
Network services and protocols A network service is a server and client communication program working in pairs. Protocol - a single standard agreement for the interaction between devices on a computer network. Each service has its own protocols. Example of a service. File and printer access service for Microsoft networks. Example of TCP, IP protocols.
>>Informatics 9th grade >>Informatics: Installation and operation of a robot modem
Computer networks. The local network
A computer network is a connection of computers to exchange information and share resources (printer, modem, disk memory, etc.).
The 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.
Based on the way computers interact, local networks are divided into:
Peer-to-peer;
- networks with a dedicated server.
Peer-to-peer local network
In a peer-to-peer local network, all computers have equal rights. Shared devices can be connected to any computer on the network.
Dedicated server network
Network structure with dedicated 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.
Less powerful computers with less disk and RAM memory are usually used as workstations.
Dedicated server network software
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.
Client software is installed on the workstation:
Operating system for workstations;
- client part of application software, etc.
Network hardware
The most common methods for connecting computers are:
Bus (usually used for peer-to-peer networks);
- star (used for any local networks).
LAN Components
To organize a local network, you need to install a network card in each PC and connect all computers using a special cable.
Sometimes the components necessary for connecting computers are already installed on the motherboard and then a separate network card is not needed.
In this case, the socket for the network cable is located on the rear wall of the system unit.
Cables
Coaxial cable – transmission speed up to 10 Mbit/s.
- Twisted pair - transmission speed up to 100 Mbit/s.
Cable connectors
Hubs (HUB or Switch) - used to connect computers on a network.
A hub can have a varying number of connection ports (usually from 8 to 32).
The overall network connection speed when using the HUB is determined by the speed of the slowest network card.
For Switch, the connection speed of any pair of computers is determined by the speed of the slowest network card in the pair (group).
Network software
To work on a local network, you need special network software.
The Windows operating system already has everything you need to set up a network.
To organize a local network you need:
Define the name of the Working Group;
- assign each computer a unique name and IP address in this Workgroup, as well as set a subnet mask address (in some cases, an explicit IP address and subnet mask address may not be set).
Modes of access to network resources
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.
Only reading
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, for example, read-only or full access.
You can get to the presentation by clicking on the text “Presentation” and installing Microsoft PowerPoint
Vikonav: teacher of computer science SZSh No. 166 Solomyansky district of Kiev Meshcherinov Volodymyr Volodymyrovich
Slide 2
Let's perform the following steps: Crimping the twisted pair We look at the MAC address of the PC's network card We register the IP address and name of the workgroup We connect the LAN of the "Star" topology Using the "Ping" command we check the signal to another PC on the network (or to a site on the Internet) We open resources in the public domain access and open resources from another PC on the network Organizing remote control of a PC over a network and via the Internet using the “Team Viewer” program
Slide 3
We will need twisted pair crimping: Twisted pair RJ-45 connectors RJ-45 crimping tool
Slide 4
Carefully trim the end of the cable using the cutter in the crimping tool.
Remove the insulation from the cable; you can use a special knife to strip the insulation of a twisted pair; its blade protrudes exactly to the thickness of the insulation.
Slide 5
3. Separate, unravel and align the wires. Align them in one row, while observing the color coding. 4. Nibble the wires so that about a centimeter remains.
5. Insert the wires into the RJ-45 connector with the bottom of the connector facing you. 6. Check if you have placed the wiring correctly. 7. Place the connector with the installed pair into the pliers, then crimp smoothly and firmly.
Slide 7
7. Place the connector with the installed pair into the pliers, then crimp smoothly and firmly. The connector is ready! Now you need to crimp the cable on the other side and you can check the quality of the resulting patch cord using a tester.
Slide 8
We look at the MAC address of the PC network card. The MAC address is the unique physical address of the network card. For Windows XP Start / Control Panel / Network Connections For Windows 7 Start / Control Panel / Network and Internet / Network and Sharing Center / Changing adapter settings (left in column) Local Area Connection
Slide 9
Slide 10
Slide 11
We register the IP address IP, DNS server, gateway - can be configured in automatic retrieval or can be registered manually depending on the network settings. (When connecting via Wi-Fi, the IP address is obtained automatically from the router) For Windows XP Start / Control Panel / Network Connections For Windows 7 Start / Control Panel / Network and Internet / Network and Sharing Center / Change adapter settings (on the left in column) LAN connection
Slide 12
Slide 13
We register the IP address IP addresses should not be repeated! Each person assigns himself one of the following IP addresses: 192.168.100.180 192.168.100.181 192.168.100.182 192.168.100.183 192.168.100.184 192.168.100.185 192.168.100.186 192.168.100.187 192.168.100.188 192.168.100.189 Author: computer science teacher MBOU Secondary School No. 32 (city. N. Tagil) Chernavin Alexey Leonidovich
Let's repeat
What is an operating system?
Operating system (OS)- a set of programs that allows the user to communicate with a computer, manage computer devices, programs and information stored in the computer’s memory.
Let's repeat
What are the main functions of the OS?
- Providing a dialogue between the user and the computer.
- Manage programs installed on your computer.
- Controlling the operation of computer devices.
Let's repeat
What is a file system?
File system is designed to organize operations on files and folders (directories).
Let's repeat
What operations does the file system allow?
- create, rename and delete files;
- transfer and copy files from one medium to another;
- search for files stored on different media;
- launch programs for execution.
Let's repeat
What programs are called file managers?
File manager- a computer program that provides a user interface for working with the file system and files
Today in class we...
- learn what is called a computer network;
- Let's look at the types of computer networks and their features.
- Let's get acquainted with different types of network resources;
The desire to transfer information from one computer to another, to provide users with shared access to technical devices, software and information resources of computers, necessitated the integration of computers into a single network.
Computer network
Based on territorial characteristics, networks can be divided into four types:
- local;
- regional;
- corporate;
- global.
local network .
This is, as a rule, a network of one organization, educational institution, etc.
According to the method of organization, local computer networks are divided into:
networks with a dedicated server.
peer-to-peer networks
In peer-to-peer networks, all computers have equal rights.
A dedicated server network has one high-performance computer that controls the entire network. This computer is called server .
It makes its resources available for sharing among other computers on the network, called clients, and can control their work.
According to the connection method, computer networks can be:
wired
wireless
To organize the operation of computers connected to a local network, you need the appropriate hardware and software:
Hardware
LAN card
Network cable
Network port
All computers on the network must be equipped with network cards. They are designed to receive and transmit information on the network.
LAN card
Computers on a network are connected using a special network cable.
Network cable
The socket for connecting the network cable is located on the rear wall of the system unit.
Network port
"Tire"
Methods for connecting computers on a local network:
"Star"
Methods for connecting computers on a local network:
Wireless LANs use an access point, and each computer must have a special wireless network card installed WiFi .
Software support for the operation of computers on a local network is provided by the operating system
Computers are connected in networks to share network resources.
Network resources (network resources) computers can be:
- technical devices (printers, modems, disk drives, etc.);
- software (system, application and instrumental);
- information resources (files with information).
The user on whose computer the resource (file, disk, folder or device) is located is its owner and has full access to this resource.
The resource owner can allow other network users to access his disk, folder, or file.
Viewing available network resources is carried out in the folder Net .
The window of this folder displays the shared resources of the network to which the computer is connected (computers, folders, files, printers).
The most important characteristic of a local network is information transfer rate it contains the amount of information transmitted per unit of time.
The speed of information transfer over a network is usually measured in bit/s .
There are no uniform rules for user behavior on a local network. Let us note only some general requirements:
- do not share your network login name and password with other users;
- If possible, save information on your computer's drive rather than on public drives.
Let's repeat
Why are computers connected in networks?
Computer network- an association of computers that ensures the sharing of network resources.
Let's repeat
What network is called local?
Computers located at short distances from each other can be combined into local network .
Let's repeat
How are computers connected into a local network?
To organize the operation of computers connected to a local network, you need appropriate hardware and software: a network card, a network cable.
Let's repeat
What types of local networks are there based on connection method?
Peer-to-peer and dedicated server networks.
Homework
