How to encourage a LAN - a local network of small enterprises. Course work: Designing a local counting measure Pobudova local counting measure

In ієrarkhіchnih local merezhakh there are a few special computers - servers, from which the information is collected, spily vikoristovuvana with different koristuvachs.

The server in ієrarchіchnykh merezhakh - tse postіyne collection of resources, which are divided. The server itself can be a client or less a server of the highest equal of the hierarchy. Therefore, hierarchical lines are sometimes called lines from the seen server. Servers and sound with high-performance computers, possibly, with a small number of parallel processors, with high-capacity hard drives, with a high-capacity tethered card (100 Mb/s and more). Computers with access to information on the server are called stations or clients.

Scrap is classified according to recognition:

Merezhі terminal service. The stench is turned on by the EOM and the peripherals are possessed, vikoristovuvane in the exclusive mode by the computer, which is connected, or be a blatant resource.

Merezhі, on the basis of which the system of management of virobnitstvom and the installation activity was induced. The stench is united by a group of MAP / TOP standards. IDA describes standards, like industry. TOP describes the standards for merging, which are used in office mergers.

Merezhі, scho to build automation systems, design. The robotic stations of such networks are based on hard personal EOMs, for example, by Sun Microsystems.

Merezhі, z urakhuvannya kah pobudovan rozpodіlenі numbering system.

All LOMs are processed in one standard adopted for computer networks - the Open Systems Interconnection (OSI) standard.

Basic model osi (Open System Interconnection)

In order to mutually, people vikoristovuyu splnu mova. Even though stinks cannot move one by one without a middle, stinks zastosovuyet indpomіdnі podomіzhnі zasob poprodіvі podomlen.

Introducing a higher stage is necessary, if the notification is transmitted from the head of the government to the end.

In order to bring the process of transferring data into circulation, machines were victorious with the same coding of data and tied one by one. For a single presentation of data from the lines of communication, by which information is transmitted, the International Organization for Standardization (English ISO - International Standards Organization) was formed.

ISO is recognized for the development of a model of an international communication protocol, within the framework of which international standards can be developed. For a clear explanation, divide її into sіm rivnіv.

The International Organization for Standardization (ISO) has developed a basic model of open systems interconnection (OSI). This model is the international data transmission standard.

Model revenge sim okremyh rivniv:

Riven 1: physical- bit transfer protocols;

Riven 2: channel- shaping frames, managing access to the middle;

Riven 3: fencing- routing, curation by data streams;

Riven 4: transport- Safeguarding the mutual modality of remote processes;

Riven 5: session- Supporting the dialogue between distant processes;

Riven 6: tribute danikh - interpretation of the danikh that are transmitted;

Riven 7: applied- Koristuvalne management of danim.

The main idea of ​​this model lies in the fact that the skin layer has a specific role in that number and the transport medium. Zavdyaks of this important task of transferring data are divided into okremi easily accessible for a look at the task. Necessary areas for zv'yazku of one equal z more-i lower-stash are called a protocol.

Oskolki koristuvachі require effective management, the system of counting measures is presented as a complex budova, as a coordinator between the heads of koristuvachiv.

With the improvement of the visceral deposit, it is possible to introduce an advancing equal model for administrative functions, which will be put on the applied equal of the coristuvach.

Okremi lines of the base model pass straight down from the dzherel danich (from line 7 to line 1) and straight uphill from the landing line (from line 1 to line 7). Koristuvatsky data are transferred to the lower rіven at once with a heading specific for the rіvnya until the next day, until the remaining rіven is reached.

On the priymalny bots of data, which are needed, they are analyzed and, if necessary, they are transferred to the distance from the turf, until the information is transferred to the koristuvalnytsky applied ryven.

Riven 1Physical.

Physically, electrical, mechanical, functional and procedural parameters for physical communication in systems are determined. The physical connection is indistinguishable from it, operational readiness is the main function of the 1st level. Physical level standards include recommendations V.24 CCITT (CCITT), EIA RS232 and X.21. The ISDN standard (Integrated Services Digital Network) may play the primary role of data transmission functions. As the middle of the transmission of these data, there is a three-wire medium wire (shielded twisted pair), coaxial cable, fiber optic conductor and radio relay line.

Riven 2Channel.

The channel rіven forms data, transferred by the 1st rіvn, ranks "cadres" of the sequence of cadres. On this level, there is an access to the transmission medium, vicarious dekilkom EOM, synchronization, manifestation and correction of pardons.

Riven 3Merezhevy.

Merezheviy rіven vstanovlyuє zv'yazok counting ї merezhі between two subscribers. This is required for the routing functions to require that the router address be present in the packet. Merezheviy rіven is also responsible for ensuring the processing of pardons, multiplexing, and cherishing streams of tribute. The most important standard that can be applied to this level is recommendation X.25 of the CCITT (for a chain of wires with commutation of packets).

Riven 4Transport.

Transportation equalizes the uninterrupted transfer of data between two mutually interacting one-by-one core processes. The quality of transportation, bezmilkovist transfer, independence of counting measures, service of transportation from one day to the other, minimization of charges and addressing of calls guarantee uninterrupted and bezmilkovu transfer of data.

Riven 5session.

The session riven coordinates the reception, transmission and communication of one session. For coordination, it is necessary to control the working parameters, manage the data flows of the intermediate accumulators and dialogic control, which guarantees the transfer of clear data. In addition, the session line will take care of the additional functions of password management, pay for the cost of resource management, dialogue management, synchronization and voice communication in the session transfer after the failure of pardons on the lines below.

Riven 6 Giving tribute.

The date of submission of data is recognized as the interpretation of data; as well as the preparation of data for the koristuvach of applied rіvnya. On this level, there is a conversion of data from frames, which are used to transfer data to the screen format or the format for other extensions of the cinema system.

Riven 7Applied.

In applied science, it is necessary to give coristuvachas the already revised information. Zim can get into the system and the application software security.

For the transmission of information via communication lines, the data is converted into the lanchy of the offensive one by one battles (double coding for the help of two stations: "0" and "1").

Transmitted alphanumeric characters are given for additional bit combinations. Bit combinations are sorted in the same code table, which can be replaced by 4-, 5-, 6-, 7- or 8-bit codes.

The number of characters represented in the course of the deposit is the number of battles that are distinguished in the code: the code for the number of characters can represent a maximum of 16 values, 5-bit code - 32 values, 6-bit code - 64 values, 7-bit code - 128 values ​​and 8- bit code - 256 alphanumeric characters.

When transferring information between the same counting systems and types of computers, it is necessary to differ, stop the next code:

On the international level, the transmission of symbolic information is based on the help of 7-bit coding, which allows coding large and small letters of the English alphabet, as well as other special characters.

National and special signs cannot be detected with the help of a 7-bit code. For the representation of national characters, the most significant 8-bit code is required.

For the correct and, then, again, the transfer of data without mercy, it is necessary to wait for the compliance with the established rules. Please note the transfer protocol.

The protocol for transferring data with advanced information:

Synchronization

Under synchronization, the mechanism of recognizing the cob of the data block of that yogo cycle will be explored.

Initialization

Under the initialization, it is necessary to understand the establishment of a contract between partners, which should be mutually modified.

Blocking

Under blocking, it is necessary to understand the distribution of information that is transmitted to blocks of data of a strictly singing maximum duration (including recognition signs on the cob of the block and the beginning of the end).

Addressing

Addressing ensures the identification of a different vicarious possession of data, so that information is exchanged at the hour of mutual modality.

The manifestation of pardons

Under the appearance of pardons, the installation of battles of parity and, also, the calculation of control battles will be reconsidered.

Block numbering

The streaming numbering of blocks allows you to restore the information that has been transferred or wasted.

Data flow management

Data flow management to serve for rozpodіlu and synchronization of information flows. So, for example, if you don’t spend time in the buffer, I’ll add data, or if you don’t finish it, they’ll be processed in peripheral outbuildings (for example, printers), reminders and/or they will accumulate.

Methods of inspiration

After the process of transferring data is interrupted, the renewal methods are used to turn to the first position of retransmission of information.

Allowed access

Rozpodil, the control of such exchanges for access to data is set as a binding point for allowing access (for example, "only transfer" or "only acceptance").

Merezhevy annex and arrange communications

As zasobi kommunikatsiy most often twisted pair, coaxial cable fiber optic lines. When choosing the type of cable, the following indications should be given:

versatility for installation and maintenance,

speed of transmission of information,

Substitution for the size of the transmission line (without additional subsidiaries-repeaters (repeaters)),

safe transmission.

The main problem lies in the one-hour security of the transmission of data, for example, the security of the transmission of data is surrounded by the most possible means of transmission of data, with the necessary security of the transmission of data. Easy expansion and ease of expansion of the cable system can be injected into the її variety /

Twisted couple

The most inexpensive cable connection is the most common cable connection, often referred to as "twisted pair". It allows you to transfer information with speed up to 10 Mbit / s, it is easy to increase, it is easily stolen. The length of the cable cannot exceed 1000 m for a transmission speed of 1 Mb/s. Advantages are low price and problem-free installation. In order to increase the noise immunity of information, it is often necessary to use a shielded twisted pair, tobto. twisted pair, placed in a screen shell, similar to the screen of a coaxial cable. Tse zbіshuє vartіst torsion bet and nablizhaє її tsіnu to tsіni coaxial cable.

coaxial cable

The coaxial cable has an average price, good pereskodny and zastosovuetsya for zv'yazku on large distances (kilka kilometers). The speed of transmission from 1 to 10 Mb/s, and in some cases it can reach 50 Mb/s. The coaxial cable is twisted for basic and broadband transmission of information.

Broadband coaxial cable

Broadband coaxial cable is not susceptible to overshoot, easy to build up, but the price is high. The speed of transmission is 500 Mb/s. When transmitting frequencies to the basic smuz for a distance of 1.5 km, a repeater is needed, or so the titles of a repeater (repeater). Therefore, the total time for the transmission of information increases to 10 km. For calculating the size of the bus topology, the tree coaxial cable is responsible for the mother on the edge of the narrow resistor (terminator).

Ethernet cable

The Ethernet cable is also a coaxial cable with a 50 ohm support. It is also called a thin Ethernet (thick) yellow cable. Vіn vikoristovuє 15-contact standard included. After all, the switch is an expensive alternative to traditional coaxial cables. The maximum available distance without a repeater does not exceed 500 m, and the distance between Ethernet lines is close to 3000 m.

Cheapernet cable

A cheap, low-cost Ethernet cable is a Cheapernet cable, or, often referred to as, thin Ethernet. This is also a 50-ohm coaxial cable for the speed of data transmission at ten million bits / s.

When connecting segments of the Searegnet cable, you will also need repeaters. The number of measurements with Cheapernet-cable may be small and the minimum amount of damage when growing. Z'ednannya merzhevy boards carried out for the help of small-sized bayonet roses, which are widely vicorous (CP-50). Additional screening is not needed. The cable is connected to the PC for additional triplets (T-connectors).

The distance between two workstations without repeaters can be a maximum of 300 m, and the distance between two working stations on a Cheapernet cable is about 1000 m.

Local counting network of subscribers, who are located on a small distance one from one (between 10-15 km). Sound like this, the lines will be at the borders of one enterprise or organization.

Information systems, prompted by the improvement of local counting measures, ensure the accomplishment of such tasks:

Data protection;

Data processing;

Arrangement of access to coristuvachs to data;

Transfer of data and results of their processing to coristuvachs.

Computing systems implement the distribution of data processing. Here the processing of data is divided between two objects: the client and the server. At the data processing process, the client form is fed to the server for the processing of folding procedures. The server vickonuetsya, secures the collection of data from the incoming correspondence, organizes access to these data and transfers the data to the client. A similar model of an enumerative network has won the name of the client-server architecture.

For a sign of subdivision of functions, local computer networks are divided into peers and nobles (archarchy networks or networks with a visible server).

In peer-to-peer networks, computers are equal one to one. Kozhen koristuvach merezhі virishuє himself, as if the resources of his computer were bestowed on the gale of koristuvannya. In this rank, the computer acts as both a client and a server. Peer-to-peer subdivision of resources is generally acceptable for small offices with 5-10 co-workers, sharing them with a working group.

Dvorangovy merezha organizuetsya s urakhuvannya server, at which koristuvach merezhas are registered.

For modern computer networks, a standard network is removed, which combines work stations and servers, and some of the work stations establish peer-to-peer lines, and some of them lie with dwarf networks.

The geometric scheme of the link (configuration of the physical connection) in the node of the link is called the topology of the link. Use of impersonal variants of mesh topologies, basic ones such as bus, ring, star.

Tire. Channel zv'yazku, scho podnuє vuzli in merezh, utavlya lamanu line - bus. Whether any vuzol can receive information in an hour, and transmit - only once, if the bus is free. Data (signals) are transmitted by the computer to the bus. The skin computer reverifies them, depending on who the information is addressed to, and accepting data, as if the stench is sent to you, or ignoring it.

With a bus topology, the middle of the transfer is in the form of a communication path, accessible day to all working stations, which all can be connected. All working stations can contact without interruption from any working station that is in the area. As computers are distributed close to one another, the organization of a computer network with a bus topology is inexpensive and simple - you just need to lay a cable from one computer to another. Extinguishing the signal from the zbіlshennyam vіdstanі obmezhuє dovzhina bus і, also, the number of computers connected to it.

Working stations be, if, without interrupting the work of all counting measures, you can be connected to it. The function of calculating the number of deposits is to become a working station.

Kiltse. The knots are united at the measure of a closed curve. The working station is navigating to the last address of the information, forwarding the request from the ring. The transfer of data is only possible in one direct way. The leather vuzol also implements the functions of a repeater. Vіn accepts and transmits the notification, but receives only more brutally to the new one. Vykoristovuyuchi kіltsevu topology, you can come to a large number of knots, virishivshi problems crossing and extinguishing the signal due to the order of the skin knot. Overpowering support is even more effective, so that more support can be sent "on the road" through the cable system one by one. It's just possible to get a call on all stations. The frequency of transmission increases in proportion to the number of working stations, which are included in the calculation.

With a ring topology, the working stations are connected one by one behind a stake, that is. working station 1 with working station 2, working station 3 with working station 4, etc. The rest of the working station is connected with the first. The communication link is fading at the ring. Laying cables in one working station to another can be foldable and expensive, especially as geographically working stations are spread far away from the country (for example, in a line).

The main problem with the ring topology is that the skin working station is guilty of taking an active part in the transmission of information, and at the same time, if one of them wants to paralyze the entire network. Faults in cable connections are easily localized.

The connection of a new working station will require a short-line closure of the line, the oscillators under the hour of the installation of the ring may be rozimknene. There are no shards for the length of the counting line, shards of it, zreshtoy, are counted exclusively between the two working stations.

Zirka. Vuzli merezhі z'ednani z center exchanges. All information is transmitted through the center, which allows you to simply check for faults and add new nodes without interrupting the workflow. Prote vitrati on the organization of channels zv'yazku here sound everything, lower at the tire that ring.

The concept of topology at a glance came from the area of ​​great EOM, in which the main machine takes and processes all data from peripheral outbuildings as an active data processing unit. This principle is established in data transmission systems, for example, by RELCOM electronic mail. All information between two peripheral working areas is entered through the central high school of the counting line.

The capacity of the building is determined by the calculation of the pressure of the node and is guaranteed for the skin working station. Kolіzіy (zіtknen) don't blame them.

The creation of a computer network for the processing of these data itself on the basis of the EOM is the most promising solutions, the shards ensure the “clearance of the day” between computers, which does not vimagaє vod koristuvach zhdnyh dodatkovyh data for the exchange of danim. Crimium computers, at the edge can be switched on and other attachments (elements of the measure), which will ensure the processing or display of data.

According to the principle of territorial distribution of elements in the borders, the computer borders are subdivided into sprat species:

• 1) local enumeration of land - recognition of the association of computers in the territory of the area;
• 2) global computer networks - do not impose a border on the space of distribution of computers that are united;
• 3) bezdotovі kom'yutern_ merezhi - allow arbitrarily change the position of the elements in the merzhі - fallow in the range of the rozashuvannya of the elements in the merіzhі stink can be implemented within the framework of local and global technology.

Local counting measures

Local counting lines (LAN) - a communication system, which supports digital information transmission channels in the borders of a fenced-in territory with high-speed channels of digital information transmission between connected extensions of a short-hour monopoly switchboard.

The work of the computer network is based on a different scheme of data transmission. An analogy for such a scheme can be the organization of telephone conversations between two persons, which are spoken in different ways, as shown in Fig. 3.11.

Rice. 3.11.

The collection of data to the skin level is determined by the merezhev protocol. Merezhevy protocol - ce standardizations set the rules for the sake of victory over the hour of data transmission. The same protocol allows computers to understand one another. Write all the protocols and those that computers send and receive blocks of data - packets (chi frames), delete the addresses of the manager and the controller, data and the control sum of the frame. For different protocols, expanding packets, their headers and formatting addresses of the holder can be changed.

The largest wide range of protocols:

• Novell IPX(InterPacket Exchange- exchange of data packets) - the main protocol for networks with the network operating system "Novell NetWare";
• TCP/IP(Transport Control Protocol/Internet Protocol- transport control protocol/Internet protocol) - a set of mutually related protocols that are closely related to one another, recognized for data transfer in UNIX and global Internet networks, but can also be used in Windows networks;
• "NetBEUI"(Network BIOS Extended User Interface - merging interface extensions) - the main merging protocol for keruvanes of the Windows operating system.

All current mesh protocols are based on the OSI model ( Open System Interconnection), as a transfer of similar data transformations, which will ensure the operation of application programs in the enterprise (Table 3.3). The lowest, the first rіven describes the rules of interaction with the application program, and the lowest, first, - the interaction with the transmission medium.

Table 33

Bagatorivne architecture of the OSI model

Іsnuє impersonal ways of integrating computers at the border. The more computers, the more such methods. Merezha topology- tse її geometrical form or scheme of physical connection of computers one by one, giving the possibility to classify and classify different dimensions.

At wide-range topology all signals of one LOM element can be accepted by any other element of the merezhі. Tsya topology lie down to passive. Computers no longer "listen" to the data that are transmitted as often as possible, and accept those of them, the addresses of which they provide the addresses of the possessor. To that, out of harmony with one of the computers, the robots of others will appear. Before wide topology, there are three main types of mesh topology: “tire”, “tree”, and “star”.

The "bus" topology is shown in Fig. 3.12 Vykoristovu one transmission channel (sound coaxial cable), ranks of the bus.

Rice. 3.12.

All computers are connected without intermediary with the bus. At such a line, it is given to go in both straight lines at the same time. At the ends of the railings, there are special plugs (terminators), which ensure the protection of electrical signals. At the time of termination of the terminators, the signal was vibrated through the ends of the cable and turned into a mesh. This merezhovy topology does not allow sloppy connections at the same point. For other circuits, the "bus" topology allows the connection of computers with a minimum of wired cable.

In a network with "star" topology, all computers are connected via a hub (hub)- special attachment for connecting a group of computers (div. small. 3.12). Hubs can be active, which allow regenerating the signal, passive, which only switch the switching function, and hybrid, which allow connecting cables of various types.

For topology "star" direct connection between computers every day. The data of the skin computer are forced up to the concentrator, which transmits the data for recognition. The main problem of such a mesh topology is that if it is possible to connect between a computer and a hub, then the mesh will continue to function normally, only one computer with a flexible cable will be connected. Mismatch topology "star" є direct result of її troubles: out of tune with the concentrator will paralyze the work of all the networks. In most cases, for topology, you should also beware of a large cable wire.

The "tree" topology is shared by a large number of "bus" topologies through a hub, to be used for the expansion of networks with a large number of computers.

In the last topology, the skin element of the mesh transmits signals to only one (another) element of the mesh. For this type of topology, the most common type of topology is the "ring" topology (div. Fig. 3.12), which is characterized by the presence of end points of the closure (the rim is closed in the ring). Data in the measure are collapsing in one straight. On the vіdminu vіd "zіrki" "kіltsyu" nebhіdny non-exploring path between computers, that poshkodzhennya cable should be made to the new teeth of all merezhі.

Definitely, it’s important to pay attention to nutrition, as the topology of the border is better. "Zirka" is richly nadіynisha, shards of a broken link in one exchange can only be produced until the inclusion of that exchange, and the entire line of the line continues to function normally. However, the "zirka" vymagaє vikoristanny concentrator (to finish the folding and expensive add-on), out of the way to sound the robot of the merezhі. In order to equalize the different topologies, it is necessary to correct the impersonal factors, which should be added to a specific line, and only after their analysis of the growth of the visnovoks on the bark and other merry topology.

When you are prompted to finish the great merezhas, often the zmіshani merezheі topologies are victorious, sometimes even smarter.

At the same time, a part of the computer mesh is important for connecting wires or cables, which act as a physical medium for transmitting data between computers. The most wide are three groups of cables.

Coaxial cable for computer merezh maє 50 Ohm hvilovy opir. The wines are built up from the middle of the living, which exudes insulation, the screen looks like a metal braid and (or) a ball of foil and an outer shell. The presence of the screen well protects the signal from electrical faults. Transmission speed 10 Mbit/s. A thin coaxial cable (RG-58, about 0.5 cm in diameter, 10Base5 standard) is connected directly to the tie adapter card and can transmit a signal up to 185 m. A thin coaxial cable with a diameter of about 1 cm (10Base5 standard) can transmit a signal to up to 500 m. This cable is connected through a special attachment - a transiver ( transceiver).

Vita pair - tse two interchanged one around one insulated honey darts. A sprat of twisted pairs is often placed in a single shell. Curling darts often helps to avoid electrical overshoots. Unshielded twisted pair (UTP - lOBaseT standard) is also widely used in LOM, allows transmitting a signal to a distance of up to 100 m and is released in decal categories. In Denmark, the category has been expanded the most, as it allows you to transfer data with a speed of up to 100 Mbit / s, and it consists of a couple of pairs of the middle port. The biggest source of non-canceled betting twists is the low resistance to electromechanical shifts. Screened twisted pair (STP) may be braided midway, and the skin pair of wires is wrapped with foil.

To connect twisted bets to the truss elements, RJ-45 connectors are used with eight contacts, similar in shape to RJ-11 telephones.

On fig. 3.13 shows the connection diagram to the intermediary board of the betting computer (topology "star") and coaxial cable (topology "bus").

Rice. 3.13.

a: 1- Merezheva board, 2 - rose RG-45 for torsion pars; b: 1- Merezheva board, 2 - T-connector, 3 - BNC sockets on coaxial cable, 4 - terminator

AT fiber optic cable digital data is expanded by optical fibers at the sight of modulated light pulses. Theoretically, the speed of transmission can reach 200,000 Mb/s, and the range is over 2 km. So is the greatest theft, and the most expensive way of transferring data. Transmitting data is not up to electromagnetic shifts, and it is important to change. Sound, one fiber-optic cable with an additional frequency sub-base can transmit data from a number of devices (digital data, telephone conversations, TV signal thinly.).

The fiber optic cable is made up of two optical fibers for data transmission in two directions. For quality, the cable may be covered with Kevlar. At the main board of the computer, with the use of a fiber optic cable, the light pulses must be converted to digital signals.

Іnfrachervone vipromіnuvannya allows you to transfer data in one place to a distance of three more than 30 meters with a speed of up to 10 Mbps. Sound infrachervone viprominyuvannya vikoristovuєtsya transfers of data between the elements of the local merezhі, yakі can often move, and zadnannya with portable computers.

For the transmission of signals between portable elements, they are vicorated by a local mesh transivery- Installed outbuildings, tied with a cable from a scrap, as they receive and transmit infrared vibration.

Radio broadcast The data is based on a variety of radio receivers and radio transmitters. Radio transmission in the narrow spectrum of frequencies is carried out on one arbitrarily assigned frequency. The distance of the call to lie in the minds of the passage of the radio, and the speed can reach 4.8 Mbit / s. The radio transmission in the smuz of frequencies allows you to establish a call between the elements of the link in a number of radio bands (channels), choosing the best call to hear the call.

At the present time, for the connection of outbuildings in LOM, a radio transmission according to the IEEE 802.11 standard, more commonly under the Wi-Fi trademark, is widely victorious. The speed of transmission in a non-dart land is to be deposited as in the case between the points that are exchanged with money, so in the case of other factors, for example, the transfer is equal. For a speed of 11 Mb/s (maximum for 802.11b), the range becomes 30-50 m. As soon as it is determined by the strength of the signal, the protocol automatically selects the optimal transmission speed.

There, de vikoristovuyutsya computers, є elektromerezі. power lines. To that, it is natural to transfer it through electrical networks like electrical energy, and th data. In this case, it is necessary to install additional cables, so that when the computer is plugged into the wall outlet, it will automatically appear as a connection to the LAN. Advanced systems that transmit data over power lines can transmit data with a speed of up to 2 Mbps. In the future, this security will be promoted.

In order for the computer to work in a local area, it is to blame for the security of a special electronic board - a network interface card (synonyms - a network card, a network adapter), as well as a connection between the computer or another element of the network with the middle. Functions of mesh adapters are different: organization of receiving and transmitting data, making it easier to receive and transmit data, forming packets of data, encoding and decoding, control over the correct transmission of data.

Merezhevі adapters are prepared and functionally up to the standards of various meshing technologies and can be covered by different data transmission speeds. The most expanded technology is Ethernet.

Merezhi Ethernet can be like “stars”, and “tires”. If a coaxial cable is selected as a data link, the Ethernet network is configured as a bus. In this case, the cable connection with the computer's intermediary adapter is connected to the help of a T-shaped BNC connector (div. small. 3.13). The sumarna dozhina cable segment merezhі sound no higher than 180 m-code.

In case of a different twisted bet, the Ethernet is configured as a “star”. Dovzhina exchange of stars (walking from the computer to the hub) may change 80-100 m.

Merezhevі adapters support other transmission channels, tobto. іsnuyu pay for work in Ethernet networks with coaxial cable and pay for work with twisted pair. There are also combined payments, which can be connected to a coaxial cable, and to bet twists.

The tether adapter is responsible for providing access to the trim medium. Access method - tse nabіr rules, yakі vyznachayut, as the computer is guilty nadsilat and receive data over the cable. All the elements of the measure are due to the victoriousness of the very method of access for zapobіgannya sprobі one-hour vikoristannya physical medium. There are three access methods: multiple access by carrier control, access by passing a token, and access by priority request. The rest of the two methods are considered to be selective, but small stations can stop the transmission of data only after the removal of the general permission.

Multiple access with carrier control. In Ethernet networks, data transmission speed is 10 Mb/s, in its own method, all computers are able to “hear” the cable and start data transmission only once, if the cable is available. Through this method is often called the method of supernition, the fragments of the skin computer are able to “catch” the medium that is being transmitted. If two computers start a transmission at the same time, the conflict is resolved and the data transmission is renewed at the same hour interval.

The test of the transfer can be vikonan immediately after the necessary transfers, which allows you to organize even a quick job in small chains. However, the speed of data transmission drops sharply due to the greater number of elements and the cost of the merezhi.

Access by passing a token. The method is victorious for Token Ring and ArcNet merging, which is able to trace the "ring" topology. The marker (especially the combination of bits) constantly circulates around the ring. In order to send data, the computer is to blame for the arrival of the marker and the request for yoga. Once the transfer is complete, the computer will allow the token and the next computer may be requested.

Access to priority request. The method is only valid for networks with concentrators that comply with the IEEE 802.12 standard (Ethernet with 100 Mbps data transmission speed - 100VG-AnyLAN). The concentrators have access to the cable, sequentially examining all the elements of the network and influencing the transmission request. Otrimavshi one hour kіlka zapіv, the concentrator gives priority to zapіє with more high priority.

When merging computers in a local area, the role of that other computer may be the same. Ring out the servers and work stations.

The server is a computer, which gives its resources to other computers in the local area. Vin is responsible for ensuring the security of data and authorization of access to them. Below are the main types of servers:

• 1) the file-server is victorious as a centralized collection of information that will become of interest to a group of correspondents;
• 2) the addendum server gives its own calculation of the pressure for picking up an "important" addendum; at the same time, on low-power clients, only the results of the work are transferred to the power supply. Most such programs are database management systems;
• 3) remote access server to serve for access from a remote computer (telephone line) to the local network;
• 4) druk server secure the bed of a variety of printers in the local area;
• 5) mail server is engaged in the transfer of electronic communications between koristuvachs.

Servers can be seenі invisible. At the first turn, the server is no longer working on the network and cannot win as a working station. In another way, in parallel with the keruvannya merezhey, the server can be vikoristovuvatsya and like a working station.

Client (working station)- a computer that uses the resources of other computers in the network and acts as a backup for information from the server.

In some ways, the computers have been placed on the servers and the clients to get smart; one and the same computer at the same time can act as a local network server, and as a work station.

AT peer-to-peer all computers are equal. The skin computer functions as a server and as a client. "Vlasniki" of the computer independently administer all the resources of the personal computer, tobto. skin coristuvach can often vikonuvaty functions of the administrator of the measure. Peer-to-peer merezhichay vikorivuyutsya with a small number of computers at the merezhі (not more than 10-15) and in quiet depressions, if the merezhі is not expected to be highly productive and equal to zahistu. Peer-to-peer measures are easy to manage and maintain and do not detract from the knowledge of special knowledge.

In a peer-to-peer network, the skin computer can override the server functions, but also the exchange functions. Sound to see the file server and that server to another. Organize the program server in a peer-to-peer network.

In the Microsoft Windows operating system, a support for peer-to-peer networks is introduced - for such a network, additional software is not required.

important

If it is necessary to organize the work in a large number of coristuvachs, then the peer-to-peer merger becomes unsatisfactory: the productivity of the merger decreases sharply and administrative problems are blamed. Larger local networks of victorious servers are specially optimized for fast data processing. In great networks, the productivity can be accumulated depending on the fact that the functions of the network are correctly divided between the servers. Name the role of the file server, the server, the program of the mail server, hack different computers.

Merezhy on the basis of the server allow you to secure centralized access control to data, data protection, regular backup of the most important information, savings for data duplication in real time (mirror disks). But the main advantage of such measures is the possibility of one-hour work and a large number of coristuvachiv for the minimum cost of productivity.

Active operating systems allow you to beat the server as an invisible server. Such a computer can perform all server functions and become a working station at once. Keep in mind, for example, that in such a mode, the productivity of the server's work is significantly reduced (for small networks, it is acceptable). Vigrash is an additional work place.

It is possible to organize a combined type of mesh. Such merezhes will overcome the advantages of peer-to-peer merging and server-based merging. With this, on client computers, operating systems can function, which only support peer-to-peer networks. Koristuvachs can apply the resources of their computers (catalogues, disks, printers). Operating systems of computer-servers in order to ensure the functioning of all server services, the necessary protection of data on the server and administrative access. Pobudov of this type of merging, ale thought of rich merging administrators, and the most flexible and rational solutions.

• Trademark rights are owned by the Association of the Greatest Manufacturers of Computers and Wireless Wi-Fi Attachments (URL: http://www.wi-fi.org).

Great companies have a great obligation to give a different character to the turnover:

• text files;
• graphic;
• image;
• tables;
• schemes.

It is important for kerіvnitstva, that all information is small in a handy format, easily converted, and transferred to any nose at the need of a hand. But paper documents have long begun to be digitized, so that a computer can avenge impersonal data, with which it is easier to work on additional automation of processes. Also, to whom they transfer the information, call and contract with partners or companies that are being revised, without trivial relocations.

Thus, the demand for the widespread supply of all kinds of companies with electronic billing appliances was blamed. At the same time, there was a food about the integration of these devices into a single complex for protection, saving and saving the transfer of files.

At the same time, it is possible to make it easier to design a local enumeration (computer) measure for business.

What is SCRAP, її functions

The circuit is connected to a number of computers in one closed space. Often such a method of victorious is used by great companies, it is a waste of time. It is also possible to independently create a small link from 2 - 3 devices by winding it in the minds of the home. The more you turn on the structure, then it becomes foldable.

See the folded hem

There are two types of connection, they differ for the folding and the presence of the stone, central Lanka:

• Rivnopravnі.
• Bagatorivne.

Rivnoznachnі, stinks of the same rank, are characterized by similarity in terms of technical characteristics. On them, the same rozpodіl functions - leather coristuvach can take access to all important documents, perform the same operations. Such a scheme is easy to manage, for its creation it does not require numerical susilla. The minus is the exchange - three more than 10 members can join the whole, otherwise the overall efficiency of the work, security will be destroyed.

The server design of a local company is more laborious, however, such a system has a higher level of protection of information, as well as a clear distribution of obov'yazkiv in the middle of the web. The computer with the best technical characteristics (suppressed, supple, with more operational memory) is assigned as a server. The center is used as a scrap, here all data is saved, from the points you can either restore or assign access to documents to other shortlisted persons.

Functions of computer networks

The main powers that need to be protected when folding the project:

• Possibility of connection of additional outbuildings. More often in the city you can find a small number of cars, with expanded companies you may need additional inclusion. In the event of an increase in tension on the tse varto, take care, otherwise it is necessary to re-plan and buy new glass materials to increase the quality.
• Adaptation of different technologies. It is necessary to ensure the flexibility of the system and її connection to various trussed cables and various PZ.
• Availability of reserve lines. In the first place, it is necessary to reach the exit point of ordinary computers. In case of failure, you may be able to connect another cord. In another way, it is necessary to ensure the uninterrupted operation of the server with a bugatory connection. You can also make sure that you automatically switch to another hub.
• Hopefulness. Equipped with uninterrupted power supplies, reserves of autonomous energy, to minimize the possibility of interruption of calls.
• Defend against third-party pleas and evil. Data that is saved can be protected not just with a password, but with a whole link of attachments: a hub, a switch, a router and a remote access server.
• Automated and manual control. It is important to install the program, so that we can analyze the network at the skin moment, and tell you about the inaccuracies for your Swedish son. An example of such software is RMON. With this, you can win special monitoring through the Internet server.

Storage of technical equipment for the design and construction of local barriers (LAN) at the enterprise

Think of the powers that be, as it is necessary to protect the hour of the project's folding. The whole process of designing starts from the warehouse of the technical department (TK). Vono revenge:

• Norms of safety of statements.
• Security of all connected computers with access to information.
• Productivity parameters: hour of reaction to the request of the coristuvach to the demanded side, throughput building, so that data is collected from the robot and the transmission delay.
• Wash away the arrogance, so that the readiness to try and start a steady work without interruption.
• I will replace the complete set of expanding the network, add-ons included, or installation of equipment in case of pressure.
• Support for various types of traffic: text, graphics, multimedia content.
• Security of centralized and remote control.
• Integration of various systems and software packages.

If TK is stored with additional needs of coristuvachіv, select the type of inclusion of all points up to one line.

Basic topologies of LOM

Tse methods of physical installation of outbuildings. The most common representations of three figures are:

• tire;
• ring;
• star.

Shinna (linear)

When folded, there is one wired cable, which leads to the computers. The main cord without intermediary connections to the server, which collects information. At the new one, there is a choice and filtering of data, an exchange of access.

Advantages:

• Vimknennya or problems with one element do not destroy the other network.
• Designing a local organization is easy to do.
• Vіdnosno low varіst installation and window materials.

Noodles:

• Zbіy or poshkodzhennya carrying cable attaches to the robot of the system.
• A small business can be connected by such a rank.
• Shvidkodiya can be in the same suffering, it is more, so the call will pass between more and less than 10 outbuildings.

"Kіltse" (kiltseva)

All computers are connected sequentially - from one attachment to another. So often robbing at times of peer-to-peer scrap. In the whole ninth of tsya technology zastosovuєtsya daedals more.

Advantages:

• There is no charge to the concentrator, the router is the other way around.
• They can transmit information as soon as a sprat of koristuvachiv.

Noodles:

• The speed of transmission in all networks depends on the tightness of the most important processor.
• In the event of a malfunction in the cable, or if there is a connection of any element, the main robot is connected.
• It’s hard to complete such a system.
• When connected to an additional working place, the following work should be interrupted.

"Zirka"

Tse parallel inclusion of outbuildings to the edge to the sleeping dzherel - server. As a center, a hub or a concentrator is most likely to be installed. All data is transmitted through the new. In such a way, a robot can operate not only computers, but also printers, faxes and other devices. At present enterprises, it is the most common method of organization of activities that can be established.

Advantages:

• It is easy to connect one more month.
• The productivity of depositing in the form of a small number of elements, therefore, is left on a stable high level.
• Just know the breakdown.

Noodles:

• The inadequacy of the central attachment attaches to the work of all coristuvachiv.
• The number of connections is wired to the number of ports of the server building.
• There are a lot of cables on the grid.
• Road possession.

Stages of software design LOM

The whole process, which takes into account the competent participation of the rich fakhіvtsіv, oskolki sled ahead to open the necessary capacity of the cable building, to fix the configuration of the application, to install and adjust the equipment.

Planning a place for an organization

Slid roztashuvat cabinet pratsіvnikіv and bosses vіdpovіdno to the topology. If the shape of the star suits you, then place the main technique in the room where the main technique is placed in the center. Tse mozhe buti office kerіvnitstva. At the different bus station, the service can be rebuvat at the most distant corridor of the destination.

Pobudov's schemes of local measures

Armchairs can be built with specialized programs for automated design. Ideally, the products of ZVSOFT company are suitable - the stench is to avenge all the basic elements, which will be needed when you wake up.

Sitka is guilty of lying:

• maximum voltage;
• sequence of entry;
• possible interruptions;
• economy of installation;
• handy supply of electricity.

Characteristics of the LOM must be selected according to the plan for the placement of the organization and the possession that wins.

Parameters of computers and framing outbuildings

When choosing and purchasing elements of the network, it is important to insure the following factors:

• Summation from different programs and new technologies.
• The speed of transmission of data and the number of devices.
• Quantity and density of cables to be deposited according to the chosen topology.
• The method of managing exchanges at the merchant.
• Protection against pereskod and zboїv winding drotіv.
• Variability and tightness of mesh adapters, transiveries, repeaters, concentrators, commutators.

Principles for the design of SCRAP for the help of computer programs

When folding a project, it is important to pay attention to the great number of nuances. Tse dopomozhe software security vіd ZWSOFT. The company is engaged in the distribution and sale of rich functional software for automating the work of design engineers. Basic CAD is an analogue of the popular, but expensive pact from Autodesk - AutoCAD, but it will turn it over for ease and ease of licensing, as well as for a more loyal pricing policy.

Program benefits:

• Intuitively intelligible, clear interface in black color.
• Wide range of tools.
• Work for the two-world and three-world expanses.
• 3D visualization.
• Integration with files of most popular extensions.
• Organization of elements of SCRAP in visual blocks.
• Pidrahunok dozhin cable lines.
• Naochne raztashuvannya elementіv and vuzlіv.
• One-hour work with graphics and textual tributes.
• Ability to install additional programs.

For ZWCAD - a module that expands the functions of basic CAD in the field of designing multimedia circuits. All armchairs are connected with an automated distribution of cables in local counting lines and yogo marking.

Advantages:

• automation of selection of switching systems;
• wide library of elements;
• parallel to the filling of the cable magazine;
• automatic matching of specifications;
• adding possession to the library;
• one-hour work of kіlkoh koristuvachіv іz data base;
• Schematic signs of the refurbishment of outbuildings and objects of furniture.

To help you create a project with a voluminous look, create yoga in 3D. Intellectual tools allow you to easily route the Crowbar to the connection points, visually identify the cable passage area, organize the line span, and visualize the expansion of technological furniture (including in dynamic mode). For the help of the component editor, you can create a library like a shaf, switching devices, cables, clamps, etc., and also assign characteristics to them, on the basis of which you can add up the specifications of such calculations. In this way, the functions of this software will help to complete the master plan for the placement of organizations from the transfer of the used lines of the scrap.

Create a project of local enumeration at your enterprise at the same time using programs such as ZVSOFT.

Good day to the readers of the blog, today I want to tell you about the local Cisco network, in simple words, so I often change the nutrition related to this topic. I have written about them in one article, and the information for future engineers will be correct.

Cisco Lifecycle

Lifecycle, English language is translated like an hour of work, or the life of your decision, it includes six stages:

• Preparing > at this stage, encourage local measures to be taken, investing in a viable economic investment for the whole project
• Planning > Evaluation of readiness to support the proposed solution, for example, what is fahivtsi, who needs to work out what integrator
• Design > At this stage, the creation of a maximum report project, in which all the wants and needs of the business with technical assistance are described
• Provadzhennya > well, here it dawned on me that those who designed, it is necessary to implement
• Robot > good operation and security of uninterrupted work
• Optimization > search for solutions or technologies, for which it is possible to improve the work of local networks.

What is the all-world computer network

After that, as we have sorted out the cycle of life and the divisions of the borders, it is necessary to know the signs, as I describe it.

Merezha computer(Computer NetWork) - the totality of computers and other attachments connected by communication lines and exchanged information among themselves according to the rules - the protocol. The protocol plays an even more important role, the shards are not enough to connect the computer with communication lines.

Below is a general scheme, as if for the help of the Internet everything will be united in one goal, I guess that the Internet can be described with a simple description, the whole merezha, so that a bunch of local merezhes are united into one great merezha. Like a bachite for a little one, you allow offices to communicate with their central offices, mobile koristuvachs to work outside or at home, light becoming mobile. I think you have now realized that such an all-world computer network.

Physical components and measures

Let's explore some of the components of the local dimension. Yake the manager stood in front of the engineers, what are they doing measures, so that from the operational memory I will attach A, the ball was transferred to the operational memory of the annex B. They gave for the account of the supplements, which are worked out for the singing protocols, the information stays and hopes to be coristuvacha. The scheme is like this:

• The card is inserted into the computer
• Switch > manage your own line to your other router
• The router > can either change the router's lanyard, or the required switch may need to change the route, and then the packets are processed by the computer with the host and are sent back as information.

How to bachite a local network (LAN), even more logical and simple.

As if to marvel at the average statistical measure of business, it looks like this. The root switch, the core of the merezhі, to the new connection to the switch of another equal, as it is fixed, I described in the article How to set the cisco switch on the 3rd equal. The entire network can be segmented by VLANs, є Cisco DHCP server or on Windows, it doesn’t matter, send all traffic that goes beyond the local network, go to the router, and go further to the Internet, static Cisco routing. Apply the patching of the Cisco router already leading.

How to pour coristuvatsky programs on the mesh

Let's take a look, see how the traffic is present in the city and how to stink on it.

• Package programs > butts can be both ftp and tftp protocols, interfacing between computers and no direct messaging of people. Here smuga is missing, obviously, important, but does not play a key role.

• Interactive programs > tse offensive type of traffic > There is already є іnteraktiv mizh coristuvachem and computers. A simple butt - the same browser or downloads to databases. So, as a courteous ocular, the hour of the system's reaction is important for a new one, but not playing the most important role, as it were, obviously, no more than a long time. A simple butt came to the work of a person, but for a long time they got nasty and stepped on his foot, that one got wet :) hvilina, And after two wines there will be gundosity, that everything is nasty pracyuє, and from the same wines, having sprung up, having drunk, that ours played football with the English, then be it a zatrimka, there will be no attack on the new viklikati fiercely, wines for an hour ochіkuvannya talk about yesterday's football.

• Programs in real time > let's look at how busy the communication channels are and here the connection between people and people. Butt can be VOIP and Video traffic, sound is more priority over video. It’s even more critical after an hour of delay, messengers can serve as a butt, on ICQ kshtalt, de traffic is minimal, but a person can take away yoga mittevo.

• P2P traffic > all peer-to-peer networks (Peer-to-Peer), with a simple butt, they can be torrented 🙂 for operators in the linkage of the link, like clogged channels, but still not the blame for one simple reason that the tightness of the links in the linkage is allowed process the current needs of supporters and business. Before speech, Skype, so itself works for the p2p protocol.

Characteristics of local merezh

When prompted by the local Cisco network, that and not only її, it is necessary to secure a low level:

• Shvidkist
• Vartist
• Bezpeka
• Availability
• Scale
• topology

Models

We have already explained the main characteristics, now let's figure out how the models should be studied. First topology, yaku guessed, called

• Bus topology > with this model, stay connected, one full data transmission bus will come out, and all participants (I will add) receive a signal that nothing is predictable 🙂 I told you about the hub. The topology is even more unsafe, since it could easily take away the data that is not recognized for you, plus the opening of the central bus, leading to the complete impracticality of the local network. We began to think that it was still possible to grow a solution and guess.

• Ring topology > transmit signals to the call. Three pluses are less staining on cables, especially for optics. One point of view.

As a result of the struggle for stability to strength, they extended the axis of such a design, FDDI underpinned the Kielce topology. Here the signals are transmitted at the opposite straight lines. Vykoristovuetsya operators zv'yazku.

• All data is transmitted through the central vuzol, where the point of reference is critical, but in modern minds, everything is duplicated, beyond the clustering. І when shaving one of the line transmissions, the lines continued to work, it was necessary to reach the line with the lower models to induce a measure.

The axis is a further development and more stable, lower mirror-like topology, ale like a legacy and more expensive. Navіt yakscho to move the core, its segments of the local lines pracyuvatimut, and check if the core is lifted.

If you are going to be a corporate measure, it is your fault to think over everything and know all the weak points, so that if possible, you will try or zadublyuvat them.

There may be another option, leather with leather, it is completely resistant to wear, but the expensive one is not real. The butt can be used for a telephone call (not a style one), it is called a commercial topology.

Prodovzhuєmo raszbiratsya in pobudovі local ї merezі and razglyany like darts vykoryvayutsya for tsgogo zavdannya.

Merezhnі droti and sockets

Twisted couple

If you want to work on local strings, you need to choose some darts for which you will win. In today's offices, most of the connections for the local area use Ethernet technology, where the signal is transmitted over the so-called twisted pair (TP-Twisted Pair), which consists of several middle twists one by one (for changing the transition) pairs of wires. The leather administrator is responsible for the nobility of the sequence of embossing this dart in order to build a new patch cord.

If there is a need for a computer cable, most often a non-shielded CAT5 cable is used, and the CAT5e version is most often perfected. Cables of similar category allow transmitting a signal with a speed of 100 Mb/s with less than two pairs (half) of darts, and 1000 Mb/s with a variation of all four pairs.

For connecting to extensions (routers, commutators, tie cards), 8-pin modular connectors are installed on the ends of the twisted bet, RJ-45 everywhere (though the correct name is 8P8C).

Keep in mind that a great twisted couple is not approved for outdoor activities. Temperature drops, influencing moisture and other natural factors, can lead to gradual collapse of insulation and a decrease in functional capacities, which, perhaps, will lead to the exit of the segment of the border from the fret. In the middle mesh cable is visible on a fresh surface from 3 to 8 years, moreover, the quality of the mesh is more likely to fall back before the cable exits the operation. For tapping on a hardwire, it is necessary to tap a special twisted pair for hardwired wiring.

Pobudova local fencing, which transmits multiple cables for interconnecting computers at the fencing, you can obviously connect them without a middle to switches or routers to roses on the fencing cards of the PC, and also another option is the receptacle. In this case, one end of the cable is connected to the port of the switch, and in the correct way, the patch panel and from it are already in the switch, and the other with the internal contacts of the socket, at the outer rose, you can connect the computer or both outbuildings.

Why can you tell me to tweak the patch panel in our local area, it's easier to build it directly into the switcher, I'll point the pluses.

On a small animal of representations, the view of the patch panel is from the front and back. Like a leather port of numbering and you can sign the number of the socket with some kind of connection, which allows you to draw a map of the grid, and look for the socket you need to borrow a couple of mittevs from you, to see that the yakby socket would lead directly to the switcher, it’s elementary to fly with a signature and then use a probe to find out.

Another thing is that the patch panel is fixed and all the cables that go into it from the back, fasten with ties, that you transfer, that you don’t tamper with the connection between the socket and the patch panel, and we have a yakbi wired directly into the switch, then bula b the ability to destroy the link with the socket for the rahunok of the fluffy sound of the drota, for example.

Merezhnі sockets can but like vbudovuvaetsya in the wall, and so і are mounted zvnі, for example, in the box. Zastosuvannya sockets replace cables, what to wash, give a more aesthetic look to your work space. So the rosettes themselves can be manually twisted as reference points of various segments in the line. For example, you can install a switch or a router near the corridor, and then install the cables to the sockets, located at all necessary premises. In this rank, you take away a few points, spread out in different parts of the apartment, until you can connect not only a computer, but also a small building, for example, add-on switches to expand your home or office space.

One more trick, which you may need when you have a cable tie, you can winch, which you can win for the connection of two twisted pairs with already wrapped RJ-45 roses. For example, you have a pair of wires 3 meters, and you need 5 meters for connecting a working space, you can wire one for two small boxes.

Also, for connecting up to one cable to two computers without switching the switch, you can switch the wires. But again, I’ll remind you that in this period the maximum speed of data exchange will be 100 Mbit / s.

How to deal with local mergers with a rich variety of components and nuances, and knowledge of all warehouses, the guarantee of success and the presence of problems with the system administrator.

This is one of the first conductors, who victorious for the creation of strings. Take away the central conductor, the ball of the insulator in the copper or aluminum weave and PVC insulation. The maximum speed of data transmission is 10 Mbit. The cable is very thin to the electromagnetic guidance. At once, the Poshkojennya is renovated in the shared (Trinibna Pike I Retelna Izolyatsiya), Ale to be in the pirol tsovoi, the dylinka prazuu is unstable: the spongens of the Elektromagnikhi hwille, the rospyujsovye to the co -cups.

In Denmark, the coaxial cable is mainly used as a conductor for the signal of satellite dishes and other antennas. At local fencing, a cable with a soft support of 50 ohms is installed, and the transmission of a TV signal is 75 ohms, stink between them. In modern computer systems, the use of a coaxial cable, it sounds, is not true, and in the article, nothing can be seen.

For example, I have a provider in Moscow via a coaxial cable that gives me internet and TV, how to start my router, and if there is, I already take the internet via rj-45 to the computer.

Dali be