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What is the difference between SCS and Local Area Networks (LAN)?

LAN is computer network, built based on the requirements of one technology that will be used on a given network, most often it is Ethernet and it covers only computers. The main difference between SCS and LAN is its independence from applications that will be used subsequently, which allows it to support a wide range of applications.

SCS is a broader concept than LAN, since it covers the transmission of information from a wide range of tasks, such as the transmission of speech, data and video images, thereby allowing integration into a single information structure computer and telephone network, fire and burglar alarm, video surveillance, television, radio, etc. A properly constructed SCS is a reliable and flexible structure that has developed means for its management, monitoring and expansion.

SCS allow you to quickly and easily change the configuration of the cable system without changing its capital basis.

Advantages of structured cabling systems over conventional ones:

• a single cable system (transmission medium) is used to transmit data, voice and video signals;
• long service life, justifying investment;
• modularity and the ability to change configuration and expand without replacing the entire existing network;
• allow the simultaneous use of several different network protocols;
• do not depend on changes in technology and equipment supplier;
• use standard components and materials (copper unshielded and shielded twisted cable, fiber optic cable);
• allow the management and administration of a minimum number of service personnel;
• allow you to combine fiber-optic and copper cables in one network.
• reduction in the cost and time of installation of systems, since the installation of the entire cable infrastructure can be carried out by one rather than several companies.

Design and installation of SCS are carried out in accordance with international standard ISO/IEC 11801. The department is implementing a quality management system for certification for compliance with the state standard DSTU ISO 9001-2001.

The work is carried out using high-quality AMP, R&M components. 100% testing and certification of delivered objects is carried out with the provision of a component or system warranty from passive equipment manufacturers (15-25 years).

Functional groups of devices on the network

The main purpose of any computer network is to provide information and computing resources to users connected to it.

From this point of view, a local area network can be considered as a collection of servers and workstations.

Server- a computer connected to a network and providing its users with certain services.

Servers can perform data storage, management databases, remote job processing, job printing and a number of other functions that network users may need. The server is the source of network resources.

Work station- a personal computer connected to a network through which the user gains access to its resources.

A network workstation operates in both network and local modes. It is equipped with its own operating system (MS DOS, Windows, etc.), providing the user with all necessary tools for solving applied problems.

Particular attention should be paid to one type of server - a file server. In common terminology, the abbreviated name is accepted for it - file server.

The file server stores the data of network users and provides them with access to this data. This is a high capacity computer random access memory, high-capacity hard drives and additional magnetic tape drives (streamers).

It operates under a special operating system that provides simultaneous access for network users to the data located on it,

The file server performs following functions: data storage, data archiving, synchronization of data changes by different users, data transfer.

For many tasks, using a single file server is not enough. Then several servers can be included in the network. It is also possible to use mini-computers as file servers.

Managing the interaction of devices on the network

Information systems built on the basis of computer networks provide solutions to the following tasks: data storage, data processing, organizing user access to data, transferring data and data processing results to users.

In centralized processing systems, these functions were performed by the central computer (Mainframe, Host).

Computer networks implement distributed data processing. Data processing in this case is distributed between two objects: client and server.

Client- a task, workstation or computer network user.

During data processing, the client can create a request to the server to perform complex procedures, read a file, search for information in a database, etc.

The server defined earlier fulfills the request received from the client. The results of the request are transmitted to the client. The server provides storage of public data, organizes access to this data and transmits data to the client,

The client processes the received data and presents the processing results in a form convenient for the user. In principle, data processing can also be performed on the server. For such systems, the terms adopted are systems client-server or client-server architecture.

The client-server architecture can be used both in peer-to-peer local area networks and in networks with a dedicated server.

Peer-to-peer network. In such a network there is no single center for managing the interaction of workstations and there is no single device for storing data. The network operating system is distributed across all workstations. Each network station can perform the functions of both a client and a server. It can service requests from other workstations and forward its own service requests to the network.

The network user has access to all devices connected to other stations (disks, printers).

Advantages of peer-to-peer networks: low cost and high reliability.

Disadvantages of peer-to-peer networks:

• dependence of network efficiency on the number of stations;

• complexity of network management;

• difficulty in ensuring information security;

• difficulties updating and changing software stations.

The most popular are peer-to-peer networks based on the network operating systems LANtastic and NetWare Lite.

Dedicated server network. In a network with a dedicated server, one of the computers performs the functions of storing data intended for use by all workstations, managing interaction between workstations, and a number of service functions.

Such a computer is usually called a network server. A network operating system is installed on it, and all shared devices are connected to it. external devices - hard disks, printers and modems.

Interaction between workstations on a network is usually carried out through a server. The logical organization of such a network can be represented by a star topology. The role of the central device is performed by the server. In networks with centralized management, it is possible to exchange information between workstations, bypassing the file server. To do this, you can use the NetLink program. After running the program on two workstations, you can transfer files from the disk of one station to the disk of another (similar to the operation of copying files from one directory to another using Norton Commander).

Advantages of a network with a dedicated server:

• reliable information security system;

• high performance;

• no restrictions on the number of workstations;

• ease of management compared to peer-to-peer networks,

Network disadvantages:

• high cost due to the allocation of one computer for the server;

• dependence of network speed and reliability on the server;

• less flexibility compared to a peer-to-peer network.

Dedicated server networks are the most common among computer network users. Network OS for such networks - LANServer (IBM), Windows NT Server versions 3.51 and 4.0 and NetWare (Novell).

TYPICAL TOPOLOGIES AND LAN ACCESS METHODS

Physical transmission medium of LAN

The physical environment ensures the transfer of information between subscribers of a computer network. As already mentioned, the physical transmission medium of a LAN is represented by three types of cables: twisted pair wires, coaxial cable, fiber optic cable.

A twisted pair consists of two insulated wires twisted together (Fig. 6.19). Twisting the wires reduces the influence of external electromagnetic fields on the transmitted signals. The simplest version of twisted pair is telephone cable. Twisted pairs have various characteristics, determined by dimensions, insulation and twist pitch. The low cost of this type of transmission medium makes it quite popular for LAN.

Rice. 6.19. Twisted pair wires

The main disadvantage of twisted pair is poor noise immunity and low information transfer speed - 0.25 - 1 Mbit/s. Technological improvements allow higher transmission speeds and noise immunity (shielded twisted pair), but the cost of this type of transmission medium increases.

Coaxial cable (Fig. 6.20) compared to twisted pair has higher mechanical strength, noise immunity and provides information transmission speeds of up to 10 - 50 Mbit/s. For industrial use, two types of coaxial cables are available: thick and thin. A thick cable is more durable and transmits signals of the required amplitude over a greater distance than a thin one. At the same time, a thin cable is much cheaper. Coaxial cable, like twisted pair, is one of the popular types of transmission media for LANs.

Rice. 6.20. Coaxial cable

Rice. 6.21. Fiber optic cable

Fiber optic cable is an ideal transmission medium (Fig. 6.21). It is not affected by electromagnetic fields and has virtually no radiation itself. The latter property allows it to be used in networks that require increased confidentiality of information.

The speed of information transfer via fiber optic cable is more than 50 Mbit/s. Compared to previous types of transmission media, it is more expensive and less technologically advanced to operate.

LANs produced by various companies are either designed for one type of transmission medium, or can be implemented in various versions based on different transmission media.

Basic LAN topologies

The computers that are part of the LAN can be located in the most random manner in the territory where it is created computer network. It should be noted that for the method of accessing the transmission medium and methods of network management, it is not indifferent to how the subscriber computers are located. Therefore, it makes sense to talk about LAN topology.

LAN topology is an averaged geometric diagram of connections of network nodes.

Computer network topologies can be very different, but for local area networks only three are typical: ring, bus, star.

Sometimes, to simplify things, the terms ring, tire and star are used. One should not think that the types of topologies considered are an ideal ring, an ideal straight line, or a star.

Any computer network can be considered as a collection of nodes.

Knot- any device directly connected to the network transmission medium.

Topology averages the connection pattern of network nodes. So, an ellipse, a closed curve, and a closed broken line belong to the ring topology, and an open broken line belongs to the bus topology.

Ring The topology provides for the connection of network nodes in a closed curve - a transmission medium cable (Fig. 6.22). 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.

Rice. 6.22. Ring topology network

Ring topology is ideal for networks that occupy a relatively small space. There is no central node, which increases the reliability of the network. Relaying information allows you to use any type of cable as a transmission medium.

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.

Tire topology is one of the simplest (Fig. 6.23). It is associated with the use of coaxial cable as a transmission medium. Data from the transmitting network node is distributed along the bus in both directions. Intermediate nodes do not broadcast incoming messages. Information arrives at all nodes, but only the one to which it is addressed receives the message. The service discipline is parallel.

Rice. 6.23. Bus topology network

This ensures high performance of a LAN with a bus topology. The network is easy to expand and configure, as well as adapt to various systems. The bus topology network is resistant to possible malfunctions individual nodes.

Bus topology networks are the most common today. 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.

Star-shaped topology (Fig. 6.24) is based on the concept of a central node 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 online.

Rice. 6.24. Star network

The star topology greatly simplifies the interaction of LAN nodes with each other and allows the use of simpler network adapters. At the same time, the performance of a LAN with a star topology depends entirely on the central node.

In real computer networks, more complex topologies can be used, in some cases representing combinations of those considered.

The choice of a particular topology is determined by the scope of the LAN, the geographical location of its nodes and the size of the network as a whole.

Methods of access to the transmission medium

The transmission medium is a common resource for all network nodes. To be able to access this resource from a network node, special mechanisms are needed - access methods.

Media access method- a method that ensures the implementation of a set of rules by which network nodes gain access to a resource.

There are two main classes of access methods: deterministic and non-deterministic.

With deterministic access methods, the transmission medium is distributed between nodes using a special control mechanism that guarantees the transmission of node data within a certain, fairly small time interval.

The most common deterministic access methods are the polling method and the transfer method. The survey method was discussed earlier. It is used primarily in star topology networks.

The transfer of rights method is used in networks with a ring topology. It is based on the transmission of a special message - a token - over the network.

Marker - official message a specific format in which network subscribers can place their information packages.

The token circulates around the ring, and any node that has data to transmit places it in the free token, sets the token's busy flag, and transmits it around the ring. The node to which the message was addressed receives it, sets the confirmation flag for receiving the information, and sends a token to the ring.

The sending node, having received confirmation, releases the token and sends it to the network. There are access methods that use multiple tokens.

Non-deterministic - random access methods provide for competition between all network nodes for the right to transmit. Simultaneous transmission attempts by several nodes are possible, resulting in collisions.

The most common non-deterministic access method is Carrier Sense Multiple Access with Collision Detection (CSMA/CD). This is essentially the competitive mode described earlier. Carrier sensing is where a node wanting to transmit a message “listens” on the transmission medium, waiting for it to become free. If the medium is free, the node starts transmitting.

It should be noted that the network topology, the transmission medium access method and the transmission method are closely related to each other. The defining component is the network topology.

LAN purpose

Over the last five years, local computer networks have become widespread in various fields of science, technology and production.

LANs are especially widely used in the development of collective projects, for example, complex software systems. Computer-aided design systems can be created on the basis of a LAN. This makes it possible to implement new technologies for designing mechanical engineering products, radio electronics and computer technology. In the conditions of development of a market economy, it becomes possible to create competitive products, quickly modernize them, ensuring the implementation of the economic strategy of the enterprise.

LANs also allow you to implement new information Technology in systems of organizational and economic management.

In university teaching laboratories, LANs make it possible to improve the quality of teaching and introduce modern intelligent teaching technologies.

LAN COMBINATION

Reasons for combining LANs

A LAN system created at a certain stage of development over time ceases to satisfy the needs of all users, and then the problem of expanding it arises. functionality. It may be necessary to combine within a company various LANs that appeared in its various departments and branches at different times, at least to organize data exchange with other systems. The problem of expanding the network configuration can be solved both within a limited space and with access to the external environment.

The desire to gain access to certain informational resources may require connecting the LAN to higher-level networks.

In the very simple version LAN consolidation is necessary to expand the network as a whole, but technical capabilities the existing network is exhausted, new subscribers cannot be connected to it. You can only create another LAN and combine it with already existing using one of the methods listed below.

Methods for combining LANs

Bridge. The simplest option for combining a LAN is to combine identical networks within a limited space. The physical transmission medium imposes restrictions on the length of the network cable. Within the permissible length, a network segment is built - a network segment. Bridges are used to connect network segments.

Bridge- a device that connects two networks using the same data transfer methods.

Networks that unite washes must have the same network levels of the interaction model open systems, the lower levels may have some differences.

For network personal computers bridge - a separate computer with special software and additional equipment. A bridge can connect networks of different topologies, but running the same type of network operating systems.

Bridges can be local or remote.

• Local bridges connect networks located in a limited area within an existing system.

• Remote bridges connect geographically dispersed networks using external communication channels and modems.

Local bridges, in turn, are divided into internal and external.

• Internal bridges are usually located on one of the computers of a given network and combine the function of a bridge with the function of a subscriber computer. Expansion of functions is carried out by installing an additional network card.

• External bridges require the use of a separate computer with special software to perform their functions.

Router (router). A complex network, which is a connection of several networks, requires a special device. The task of this device is to send a message to the recipient in the desired network. Such a device is called a router.

Router, or router, - a device connecting networks different types, but using the same operating system.

The router performs its functions on network level, so it depends on the communication protocols, but does not depend on the network type. Using two addresses - the network address and the host address, the router uniquely selects a specific network station.

Example 6.7. It is necessary to establish a connection with the subscriber telephone network located in another city. First, the address of the telephone network of this city is dialed - the area code. Then - the node address of this network - phone number subscriber The router functions are performed by PBX equipment.

The router can also choose the best way to transmit a message to a network subscriber, it filters the information passing through it, sending to one of the networks only the information that is addressed to it.

In addition, the router provides load balancing in the network by redirecting message flows across free channels communications.

Gateway. To combine the LAN completely various types, operating on significantly different protocols, special devices are provided - gateways.

Gateway- a device that allows you to organize data exchange between two networks using different communication protocols.

The gateway performs its functions at levels above the network level. It does not depend on the transmission medium used, but depends on the data exchange protocols used. Typically a gateway converts between two protocols.

Using gateways, you can connect a local area network to the host computer, as well as connect a local network to a global one.

Example 6.8. It is necessary to unite local networks located in different cities. This problem can be solved using global network data transmission. Such a network is a packet switching network based on the X.25 protocol. Using a gateway, the local area network is connected to the X.25 network. The gateway performs the necessary protocol conversions and ensures data exchange between networks.

Bridges, routers and even gateways are constructed in the form of boards that are installed in computers. They can perform their functions both in the mode of completely separating functions, and in the mode of combining them with the functions of a computer network workstation.

In the modern world, local networks have become not only necessary - they are actually necessary to achieve a good level of labor productivity. However, before you start using such a network, you must create and configure it. Both of these processes are quite difficult and require maximum concentration, especially the first one. An incorrectly designed and configured LAN will not work at all or will function completely differently from what is needed, so creating a local network should become the focus of the person doing it.

What is a local network

As a rule, the creation of such communication systems is caused by the need for collective use of data by users who work on remote computers. A LAN not only allows for almost instantaneous exchange of information and simultaneous work with files, but also allows you to use network printers and other devices remotely.

A local network is a complete set of software and hardware resources aimed at creating a single information space. In fact, this is a number of computers located at a distance from each other and connected by a communication line - a cable. The main difference between a LAN and other types of networks is the short distance at which the workstations are located.

Pre-project preparation and design

Before you create a local network, you must first design it, that is, plan the process of its creation. This stage is one of the most significant, since the LAN includes a huge number of components and nodes.

Initially, a technical specification is drawn up based on primary data, defining several points:

• Functions and tasks of a LAN.
• Selected topology.
• List of available equipment.

Only after deciding on these points can you begin designing. The project itself must contain LAN diagrams, network equipment placement points, and a list of necessary software and hardware.

A local network is a complex mechanism, but if it is designed correctly and the equipment is selected in accordance with the requirements, then the likelihood of problems arising in the operation of the communication mechanism becomes minimal.

Required Hardware

There is a list of equipment without which no LAN can function. It includes:

• Data lines. The most commonly used cables are coaxial cable and optical fiber. In this case, the length of the coax cannot exceed several hundred meters, however, if it is necessary to extend the network over long distances, special repeaters are used - signal repeaters that prevent it from fading.
• Communication equipment: network cards (devices that perform duplex information exchange between the computer and the data transmission medium), hubs (break the network into separate segments, physically structuring the network), routers (take on the choice of the packet transmission route), switches (logically divide the LAN into segments, combining several physical circuits), repeaters (provide signal restoration, allowing you to increase the length of the transmission medium), transceivers (amplify the signal and convert it into other types, allowing you to use different data transmission media).

List of software tools

No LAN can do without software. Required programs for a local network include:

• Operating systems of worker nodes. The most commonly used OS remains Windows 7, although Windows XP is also not losing ground.
• Network operating systems installed on servers represent the basis of a LAN, since it is impossible to set up a local network without them. Exactly these software take control of all data flows between the main nodes and secondary nodes, providing the possibility of collective access to network resources. Typically, Microsoft operating systems are used: Windows Server 2003 or 2008.

• Network services and applications that allow users to access deleted files, printouts of documents on network printer, viewing worker nodes on the network, and sending email messages. The implementation of such services is carried out using software.

Creation and installation of LAN

Installation and adjustment work takes the most time, since creating a local network has to be done in several stages:

• Before you begin installing communication lines and switching devices, you must first prepare the room.
• Next, you can lay the cable, as well as install the necessary equipment.
• Server and workstation devices should be connected to the cable communication line.
• After this, the software is installed and configured.

Installation of cable and equipment has a number of features, so if you have difficulties with how to connect a local network, better solution leave this issue to specialists.

Connecting two computers to a LAN

In some cases, it may be necessary to combine two computers into one network, for example, to create a common information space. This is not very difficult to do if you follow a certain algorithm of actions:

• If necessary, install network adapters in both computers, not forgetting the drivers.

• Purchase a crimped network cable for connection. If you have the necessary knowledge and skills, you can do crimping yourself - a local network of two computers will not be of worse quality.
• Connect both workstations with a communication line.
• Configure the LAN in a specific order.

Algorithm for setting up a local network between two computers for Windows 7

• Select the Start menu, then click right click mouse on the “Computer” icon, enter the “Properties” submenu.
• You need to find “Computer name and domain name” in the list, and then select the option to change parameters.
• Working title computer must be changed by clicking on the corresponding icons.
• The group name should remain unchanged - “Workgroup”, however, the computer names are changed to “pc1” and “pc2” for the first and second subscriber, respectively.
• You can now click OK and restart your computer.

In most cases, you may need to assign each node a unique IP address:

• From the Start menu, select Settings and then Network Connections.
• Right-click to open the “Properties” submenu next to the “Local Area Connection” icon.
• In the “General” tab, select “Properties” of the “Internet Protocol” item.
• Make active the line “Use the following IP address” and enter the value 192.168.0.100. After this, save the changes made.

Local network and Internet

Work nodes united in a LAN can be connected to the Internet. A local network, to which the Internet can be connected in two ways, will work at a speed divided in two.

The first way to connect is to use a router, which is assigned an identification IP address. And in the second case, you can use a wireless connection.

In this case, a local network is the interaction of two computers, a master and a slave, so the IP address is registered in the gateway of the main one, which is previously connected to the worldwide network.

If the LAN is based on the use of a server, each workstation must have an individual IP address, and the proxy server through which access to the Internet is specified in the browser settings.

Wireless LAN

A wireless local area network is a subtype of LAN that uses high-frequency radio waves to transmit information. WLAN is an excellent alternative to a conventional cable communication system, having a number of advantages:

• Improved labor productivity. WLAN makes it possible to use the Internet without being tied to one room. You can freely change your location without losing your internet connection.
• Easy installation and configuration, financial savings and reliability - all these factors are due to the absence of a cable communication line.
• Flexibility. Installing a wireless network is possible where it is not possible to lay a cable.
• Possibility of expansion. Network scalability is greatly simplified thanks to wireless network adapters, which can be installed on any worker node.

WLAN has a certain range, which depends on the characteristics network devices and noise immunity of the building. As a rule, the range of radio waves reaches 160 m.

Necessary equipment to create a wireless local network

An access point is used to connect other workstations to the network. This device is equipped with a special antenna that controls full-duplex data transmission (send and transmit) using radio signals. Such a point can transmit a signal at a distance of up to 100 m indoors and up to 50 km in an open area.

Access points significantly expand the computing power of the entire communication system, allowing users to freely move between each of them without losing their connection to the LAN or the Internet. In fact, these radio points act as hubs, providing connection to the network.

Using access points allows you to scale up your entire wireless LAN by simply adding new devices. The number of subscribers that one radio point can support generally depends on the network congestion, since the traffic is divided equally between each user.

Wireless LAN: Windows 7. Setting algorithm

First, you should prepare an ADSL modem with WiFi technology, as well as client points with connected wireless adapters. After this, you can start building a wireless LAN:

• Connect the modem to the electrical network.
• Run the WLAN Setup Wizard on the client device.
• Select the SSID from the list of found wireless networks.

Access point setup:

• The first step is to configure the properties of the TCP/IP protocol by specifying the IP address and subnet mask.
• After this, specify the value of the DNS server, since it is not possible to fully configure the local network without this parameter. In most cases, it is enough to enable the option to automatically assign a DNS address.
• It is also mandatory to configure the parameters of the wireless network itself, in which security is important.
• At this stage, you need to configure the Internet connection and filtering for the Windows 7 firewall.
• And lastly, the wires are connected and the functionality of the WLAN network is checked.

To create an optimal information space, you can combine types of networks - cable and wireless, allowing you to use the advantages of each of them for the benefit of the enterprise. However, it is important to remember that in our time it is increasingly used wireless network WLAN, which has all the advantages of cable networks and lacks their disadvantages.

After completing the creation and configuration of the local network, it is important to provide for its administration and the ability to Maintenance. Even if the installation of a LAN is done perfectly, during its operation various malfunctions in the hardware or software almost inevitably occur, which is why maintenance must be regular.

With their help, users can work with the same resources, programs, data, without leaving their own workplace.

What is LAN?

The most common type of network is local

A LAN is a computer network that connects local machines of users located at some distance from each other. Although the range of such a network reaches several kilometers, it is usually used to connect computers over a short distance. As a rule, these are work machines of one enterprise or home personal computers.

LAN Configuration

According to the configuration, local networks with and without server control (peer-to-peer) can be noted.

Peer-to-Peer Local Networks

In such networks, all computers are similar in technical specifications. A peer-to-peer LAN is a local network in which each workstation can perform all available functions of both a client and a server. To effectively distribute the load on such a LAN, the number of participating computers cannot be more than 10. Otherwise, the performance of the entire network will suffer.

Server-managed networks (multi-level)

In such LANs, one of the computers is different better performance, memory capacity and other indicators. Such a PC is assigned to a LAN - these are computers with high performance and a large amount of memory compared to user local machines. It is he who ensures the interaction of other computers on the network, stores publicly accessible files and organizes access to them, transfers data to the client in the form of information for processing or the final result. LANs in which the server is used only to host shared data are called dedicated networks. file server. Along with such systems, there are LANs in which the server also carries out the work and the client receives only the result. These are so-called client-server systems.

LAN topology

All computers on the network are on physical level connected to each other. LAN topology is a way of connecting local machines. Nowadays, local networks use connection methods such as bus, star and ring.

Bus topology

In a LAN, the installation of which is planned according to this topology, a single cable is used during assembly, to which the local user computers are connected. Thus, information from one machine passes through all the others. The workstation to which the data is addressed selects necessary information from the general flow.

Advantages of LAN bus topology:

• failure of one of the local computers does not affect the operation of other machines and the network as a whole;
• relatively simple setup and design of a LAN;
• relatively low cost Supplies(with a short range, for example, within one organization).

Disadvantages of topology:

• cable damage blocks the operation of the network as a whole;
• limited range and small number of users;
• relatively low performance (depending on the number of computers on the network).

Star topology

A topology of this type involves the interaction of local computers through network equipment (hub or hub), which provides parallel connection working machines. Each station is connected to the central device via network card separate cable. As in the previous type of topology, outgoing data is available to all computers on the network and is accepted only by the user for whom it is intended.

Topology advantages:

• ease of organizing a new workplace;
• high performance;
• quick troubleshooting or cable breakage;
• Network operation is not affected by faults of individual local machines.

Disadvantages of topology:

• failure of the central device stops the operation of the entire network;
• the number of users is limited by the number of ports on the central device;
• uneconomical cable consumption;
• the cost of purchasing a hub (or other network equipment).

Ring topology

The LAN, which is installed according to the rules of this type of topology, consists of working machines connected in series, forming a ring. Data in this case passes from one computer to another and stops at the one to which it is addressed.

Advantages of the ring topology:

• there are no costs for network equipment (hub, router);
• the ability to transmit information by several computers simultaneously.

Disadvantages of topology:

• the performance of the entire network depends on the performance of each computer;
• if a cable breaks or one computer fails, the functionality of the entire network is blocked;
• complexity of setup and configuration;
• organizing a new workplace temporarily paralyzes the work of the LAN.

The “ring” topology is practically not used in practice due to its general unreliability, but is subject to various modifications.

Currently, almost no organization can do without a LAN. Star topology networks are more common due to their reliability and fault tolerance. LANs of the “ring” topology, on the contrary, do not meet modern performance and security standards. However, LANs in general have become a part of our lives and contribute to the efficiency of any enterprise.