Local networks of personal computers. Installation of a fence, installation of software security. Hardware and software security. More lessons – Hypermarket knowledge 2

For connecting computers in local networks, network adapters (merezhevі cards), concentrators, switches, routers are most often used.

Let's take a closer look at the skin type of installation.

Merezhevy adapter– This attachment is needed for connecting a computer to a local network. Merezhevy adapter is installed in a different slot (pin) of the computer's motherboard, like adapters, like other functions, for example, a video adapter. Merezhev adapters can be classified according to the following signs:

· Fallow according to the type and capacity of the vicorist in the computer of the internal bus;

· Fallow of the type adopted in the measure mesh technology- Ethernet, Token Ring, FDDI only;

· Zalezhno to the type of medium (channel) transmission of data - coaxial cable, fiber optic cable, twisted pair cable.

Merezhnye adapter comes to the cable for additional special connectors. For the cable, a twisted pair is twisted with a connector type RG-45, which is called a pink rose for connecting to a telephone. For connection to a coaxial cable, the so-called BNC connectors and T-connectors are used. Establish mesh adapters, which use the principle of interplay without dart. At this time, tryoma head types jetless transmission these are radio calls, calls in the micro-wave range and infrared calls. We will expand the most, in this hour, with the option of organizing a non-drotove local network WIFI whistleblower possession. WiFi is an abbreviation for "Wireless Fidelity" and is a standard jetless access, which ensures the speed of transfers up to 54 Mb/s.

The leather mesh adapter has a unique internal number, so called MAC address, which allows you to uniquely identify the underlying information in the middle of the mesh.

Different types cables vikoristovuyutsya like a nose, or the middle of the transmission of data. Although wireless data transmission technologies become the most popular ones, the main type of carrier for tethered communications is the cable. The most wide-ranging cables of offensive types:

· Cable type twisted pair;

· coaxial cable;

fiber optic cable.

Twisted pair cable– the largest extension of any type of cable, there are two types: unscreened and twisted pair. The internal structure is made up of a number of twisted pairs of copper wires, honed with a grounded sheath of a mid mesh, or aluminum foil at a screened bet. Іsnuє kіlka typіv nekranovanoї torsion bet. In Denmark, the type UTP-5 (UTP - Unshielded Twisted Pair) is the most victorious. UTP-5 cable provides secure transmission up to 1000 Mbps. The cable is unscreened, twisted pair - the most found and easy to install type of cable. Ale in the new є nedolіki. The cable is sensitive to the crossover from the side of the outer electromagnetic sockets and the mutual signaling between the cable wires. Dovzhina cable segment, tobto. the distance from the computer to the signal (repeat) cannot be overwhelmed by 100 meters, the signal is weakened by the cable.

Shielded Twisted Pair cable (STP – Shielded Twisted Pair) is smaller in the world up to standard electromagnetic inlets, more folding in the installation. The valley of the cable segment is surrounded by 100 meters.

coaxial cable guess the cable, which will be used for connecting the antenna to to a booth TV. Transmission speed for cim type of wearer to become 10 Mbit/sec. The length of the cable segment can be from 185 to 500m, fallow type coaxial cable. The widest nabula is called "thin" marking cable RG-58 and "thin" marking cable RG-8 and RG-11. The Danish type of cable is old and there are few twists at a time.

fiber optic cableє in the given hour we found, but also the most expensive medium for the transmission of information. Optical fiber is made from quartz, the basis of which is silicon dioxide. The cable is folded from the central fiber conductor, which expands the light signal honed by the smaller fiber ball. An indication of the breaking of the light exchange at these two balls of different sizes. There are two types of cables: single-mode, in which only one interval can be expanded, and multimodal, in which a large number of changes can be expanded. In a single-mode fiber, the diameter of the central fiber conductor is smaller, while it is lower in a multi-mode fiber. Transmission speed at vikoristanny this type the cable can reach 10 Gb/s (10000 Mb/s). Fiber optic cable is victorious mainly in global and regional areas, as well as on major highways. local mesh.

concentrator(bagatoportovy repeater, or HUB) - all attachments, which vikoristovuetsya for the union of okremikh working places (computers) at the local border. Modern hubs may, as a rule, have 8, 12, 16, 24 or 48 ports (pins) for connecting computers. Mustache of the concentrator equal. When the signal is removed from one of the connections to the new computer, the concentrator broadcasts all other ports. Thus, the concentrator is the central point of connection of computers at the border. Krіm funktії ї z'єdnannya kom'yuterіv, concentrator can vykonuvat schelka functions. Tse: strengthening (repetition) of the signal, auto-segmentation ( automatically turn on faulty ports), ensuring the collection of statistics from the merger. Concentrators can be connected one by one to increase the size of the network.

Switch(switch) – chain of attachments, which can also be used to combine computers or other segments in local networks (LZ). On the view of the concentrator, the switch, when the signal (data packet) is removed from one of the connections to the new computer, does not transmit to the port port, but transmits only to that port, until the computer is connected, which receives the data packet . As a result, the speed of data transmission increases, the shards in the measure shorten the number of colisms characteristic of Ethernet technologies.

Drugs may be powerful overgrowth of cob projects. For the growing companies grow and LZ. p align="justify"> Change the profile of the activity or the organization of the robot company can reconfigure the company. It becomes obvious if:

• it is unacceptable to stand at the cherry for a long time twill printer;
• zbіlshivsya hour to the database;
• We have changed so much about the protection of information.

Merezhі can not be expanded beyond the rahunka of a simple addition of working stations and cable laying. Be it topology or architecture can have its own infrastructure. However, є outbuildings, yakі can:

• segment the LZ so that the skin segment becomes an independent LZ;
• combine two LZs into one;
• Connect LZ to other networks for sharing them on the Internet.

Such attachments can be seen: repeaters, bridges, routers, router bridges and gateways.

Repeaters

These attachments, like receiving a fading signal from one segment of the merezhі, reinforce it and transmit it to the advancing segment, which increases the transmission distance between the other nodes of the merezhі (smaller below).

Connecting a repeater to a LAN

Repeaters transmit all traffic in both directions and work on physical equal OSI models. Tse means that the skin segment is responsible for the same: packet format, protocol, and access method. So, behind the help of a repeater, you can combine two Ethernet segments into one, and not Ethernet and Token Ring.

However, the repeaters allow you to connect two segments, which are different physical media for signal transmission (cable - optics, cable - a couple of thin ones). Deyakі bagatoportovі repeaters work like bagatоportovі concentrators that connect different types of cables.

The zastosuvannya of repeaters is right at the peaks, if it is necessary to improve the obezzhennya for the dozhina segment of the chi for the kіlkіstyu RS. Moreover, the traffic from the segment in the region does not generate increased traffic, and the variability of the LOM is the main factor. It is due to the fact that the repeaters do not lose their functions: isolation and filtering.

So, when transmitting a segment of leather bits of data from a segment, stinks will transmit both created packets, and packets that are not assigned to that segment. As a result, the problems of one segment appear on the other. Tobto. zastosuvannya repeaters do not ensure the function of segment isolation. In addition, repeaters will expand as much as possible all wide packets. If the attachments are not detected on all packets, otherwise the packets are permanently accessed by the extensions, if they do not seem to be, the productivity of the network drops, so that the repeaters do not filter the signals.

Bridges

Mіst - tse attachments, scho z'ednuє dvі merezhі, scho win the same ways of transferring data. Qi attachments, like repeaters, can:

• zbіlshuvati rozmіr merezhі and kіlkіst RS in nіy;
• connect different mesh cables. Prote important їх відміністию and those who stench work on the channel level of the OSI model, that is. on a higher, lower repeater and pay more features of the data that are transmitted, allowing:
• change the shape of the signals, but the bugs are less on equal packets;
• connect various segments of a network (for example, Ethernet and Token Ring) and transfer packets between them;
• increase productivity, efficiency, safety and reliability of the measure (which will be discussed below).

Principles of robotic bridges

The work of the bridge is based on the principle that all nodes in the network must have unique addresses, and they can transmit packets that follow the addresses of the node of recognition (small below).

Butt of complexation of segments of LOM with vikoristanny bridges

With access to the merezhі, mіst:

• hears all traffic;
• check the address of the gerel and the owner of the package;
• future routing table;
• transmits packets to the address of the acceptance node.

Mist maє deaky "іntelekt", oskolki vivchaє, where to send the data. If packets are sent across the bridge, the addresses of the senders are stored in the memory of the bridge, and the routing table is created. On the cob, the table is empty. Then, if nodes transmit packets, their addresses are copied to the table. Mayuchi tsі data, mist vyvchaє roztashuvannya kom'yuterіv in the segments of the merezhі. Listen to the traffic of all segments and receive a packet, search for the address of the transfer in the routing table. If the address of the dzherel was not found, then add it to the table. Let's check the address of the owner of the DB of the routing table.

• If the owner's address is in the table and the addressee is in the same segment with the dzherel, the package is displayed. Qia filtering changes the merging traffic and isolates the segments of the merging.
• Like the owner's address is in the table, but the addressee and the dzherelo are rebuyed in different segments, the place is transmitting the packet through the required port of the required segment.
• Since there is no address in the table, the packet is relayed to all segments, moreover, the signals are accepted.

In short, it seems that the mist knows the place of the roztashuvannya vuzla - the addressee, vin transfers the package to you. In another way - broadcast the package to all segments.

The reviewed option is the simplest, so we call the bridges clear. In this hour, you need to know the bridge with the spanning tree algorithm, the bridge with routing from dzherel and in.

Designation of bridges

1. The bridges allow to increase the distance of the entanglement of the fence, working like a repeater. With this, it is allowed to cascade the CROWN through the bridges. Moreover, tsі LOM can be different.
2. The choice of bridges promotes the productivity of a company through the possibility of segmentation. Shards of the bridge of the building filter the packages with certain criteria, then a large margin is divided into sprats of segments, connected by bridges. Two small segments are closer to each other, the lower one is large, so that the traffic is localized in the boundaries of the skin segment.
3. Zastosuvannya bridges improve the efficiency of robotic meshes, so for the skin layer (segment) it is possible to overcome different topologies and the transmission medium, and then bridge them with bridges. So, for example, if in other PCs connected by twisted pairs, then a bridge can be connected with a corporate LOM optical main line. Because win a bet cost cheaply, to save pennies, and the base highway (which gets more traffic) will win the middle of a high throughput capacity.
4. Bridges allow you to get more security (zahist) of tribute for the account of the fact that they can be programmed for the transmission of less than quiet packets, as if to avenge the addresses of the wrong officials and oberzhuvachivs. Tse allow you to live near RS, building facilities and receive information from other countries. For example, at the merezhі, scho serving buhoblik, you can put a place, which will allow you to receive information only to deyaky zvnіshnіm stations.
5. Bridges zbіlshuyut nadіynіst that vіdmovostіykіst merezhi. With a segmented measure, a vіdmova, whether or not a pіdmеrezhi, will not bring all the others to a grain. In addition, if a single file server goes out of tune, it attaches the whole mesh to the robot. If, for the help of internal bridges, two file servers are connected to insure one of one, then:

• growth of vіdmovostіykіst merezі;
• decrease the cost of traffic.

Distinguish local and distant bridges. In the distance, the bridges wink at the great chains, if the surrounding segments are connected by telephone (or other) communication channels.

However, if for the connection of two cable segments of the LOM there is only one local location, then at large networks it is necessary to achieve two distances, connected via synchronous modems to the visible channel of the link (small below).

Vikoristannya two distant bridges

Routers

Router - tse attachments for the connection of a network, which vikoristovuyut different architecture and protocols. Pratsyyuyuchi on the twill line of the OSI model, the stench can:

• commutate and straighten the packages through the sprat line;
• choose the best way for their transmission;
• bypass the wrong channels;
• to filter wide notifications;
• children yak bar'єr bezpeki mizhami.

The router at the top of the bridge has its own address and wins as an intermediate point of recognition.

To transfer information by channels, it is necessary to convert computer signals to signals of physical media.

For example, when transmitting information over a fiber optic cable, the data presented in the computer will be converted to optical signals, for which special technical attachments are used - merezhni adapters.

Merezhevі adapters (merezhnі cards) - technical attachments, wi improving the functions of computers obtained from communication channels.

Merezhev adapters are connected to the channels of communication. For dermal appearance, the channel needs a type of lace adapter. The adapter is inserted at the right socket of the computer's motherboard and connected with a cable from the third adapter of the other computer. On the border cards, put the addresses of the computers at the border, without which the transfer is impossible. If information circulates as much as possible, be it fencing computer choose from it only that which is recognized by youma itself. Vynazhayetsya vіdpovіdno to the computer's address.

Conectory (wake-up callers ) for connecting cables to the computer; roznіmannya for z'єdnannya vіdrіzkіv cable.

Transivery increase the rate of data transfer rate over the cable, to increase the signal reception from the least and the manifestation of conflicts.

Khabi (concentrators) that commuting habi (commutators) expand topological, functional and quickness computer merezh. Hub with a set of different types of ports allows combine segments and networks with different cable systems . It is possible to connect to the hub port as an okremiy vuzol merezhі, and another hub segment to the cable.

Repeaters (repeater) strengthen the signals that are transmitted over the cable for some reason.

For the construction of local merezzh, such outbuildings are built, as if to compete with each other for recognition of their possibilities:

Mist (eng. Bridge) - pov'yazuє two local borders. Transferring data between merezhami in a batch way, not slacking off the daily changes. Below the little one, there are three local borders, connected by two bridges.

Here the bridges created an expanded barrier, as if to secure access to previously inaccessible resources for their coristuvachi. For the most part, bridges can filter packets, protecting the entire network in local data flows and skipping the names of those data, which are recognized for other segments in the network.

router (Eng. Router) joint measures with a global protocol more effectively, lower locally. Vіn allows, for example, splitting large details of more frills, ensuring the interplay of local fringes from the size of the package.

The router can forward the packets to a specific address (there is less opportunity to filter out non-essential packets), choose the best route to pass the packet or more. What folding and more merezha, Tim more vygoda vіd vikoristannya routerіv.

bridge router (eng. Brouter) - a hybrid of a bridge and a router, which helps to reverse the routing, where it is possible, and then, in case of failure, switch to the bridge mode.

Gateway (eng. GateWay), on the vіdmіnu vіd bridge, zastosovєєtsya vіpadki, if mérezhі, scho zadnuyutsya, mаut raznі mezhezhі protocols. Information that came to the gateway in one line, transforms into another notification, which helps the advancing line. In this rank, the gateways do not just close the lines, but allow the construction of a single line. For additional gateways, local networks also connect to mainframes - universal hard computers.

Seeing this topic, you know:

Yakі іsnuyut raznovidi merezha;
- What are the main components of the measure;
- how to exchange information between computers;
- yaki technical background ensure the work of the computer system;
- yakі channels zv'yazku vikoristovuyut at computer communications;
- about the role of modems and mesh adapters in the mesh.

See computer mesh

Computers occupy more and more important space in the life of the people. Merezhi can unite information resources like small businesses, and great organizations, like occupying each other's places in the distance, arranging for an hour in different lands. It determines the way of connecting computers between each other and the type of the company: local, regional, corporate, global.

Local networks

Show your own computer between the polyclinic and the central computer, to remove information about all patients. At the office of a skin doctor there is a computer, on the screen of which, for consumption, you can see information about a particular sick person. The medicine is updated, taken from the database of the central (head) computer, and stinks become available to other doctors, for example, to a physiotherapist, neuropathologist, cardiologist. In addition, this information is displayed on the computer of the registry, the patient can make a referral for obstezhennia or by taking him to the necessary doctor. At the computer, you can also save information about the distribution of robots and fahivtsiv, I can see coupons for admission before them.

Computer mesh can be owned and trade enterprise. Here s її help you can collect information about the goods and їhnyu vartіst, obtain information about sales, conduct an oblіk yakostі of the goods sold and іn. All information is collected centrally, on the server.

The computer of the network can connect the computers of all schools, installed in various working areas: in the administration offices, in the library, in the computer science classes and in other offices. It is possible to unite for help, for example, two or three home computers of learning, how to live in charge.

In the office, working in the middle, different spіvrobіtniki may have access to the very internal sources of information for the preparation of various calls, laying out the layout and planning of the social activity of the enterprise. Special merezhevі programs allow you to automatically plan pickings, picking up the most in the distance for all workers at the hour, the boss can revise, chiconan yogo handover, yakі vіn rosіslav by measure, and so on. mystic meaning. As a rule, such lines are laid out by computers, spread out on small stands (about 50-100 meters) at the borders of houses, and that is why they are called local (mistsevi). Close to 90% of the information that circulates in such organizations is the information of a medical organization.

Local merezha - z'ednannya computers, roztashovannyh on small vіdstany one type of one.

Regional and corporate measures

Not infrequently, in the same office, schools and polyclinics, there is a need to take information from other similar organizations. At times among themselves, computers are installed, roztashovani at one chi and many offices.

Reveal the system of saving information in libraries. Here it is necessary according to the skin book of the mother of the difference: name, data about the authors, identification, number of obvious copies, annotation and change. If such information is made available to a great number of libraries, then it is possible to improve the services of readers, improve the organization of the inter-library fund for the exchange of books. Consolidation of libraries from a centralized computer network allows you to provide all libraries with access to any necessary information about books.

From the central library, it can be connected like a library, if there is only one computer, then the library, in which a local border is installed. For communication with computers, you can use a telephone line. Such a network already has regional significance. As an example, you can build a network of libraries in St. Petersburg and the Leningrad region.

Regional merging - combining computers and local merging common problems regional scale.

Let's guess about those, how the cash vouchers are made. Behind the request of any cashier-operator, information about the presence of free places at the train, the number of free tickets is displayed on the monitor. For the ticket of the passenger, the cashier through the fence to enter at the central computer asks for a receipt and draws up the sale. Moreover, the payment for the place is immediately forfeited for a distant sale. Please state that all computers were not connected to the measure. Todi absolutely used the sensation of victories, oskolki after a skin working day, it was necessary to work hard changes about the presence of available places at the skin-friendly computer, to tell other cashiers about unsold tickets and start thinking, how to organize the next sales ticket.

The centralization of the mesh easily overcomes such problems. Sale of tickets for one and the same route can be conducted from a number of places. And such a network can no longer be called local. Won to serve as a collection of information for one company and the association of firms and that is called corporate (like the word "corporation" - association).

Corporate merging - local merging at the boundaries of one corporation.

Corporate services are assigned to serve customers at different locations, for example, at hotels. The stench can appear at the borders of one corporation branch, which is in different countries. The information may be changed by practitioners in order to gain access to it. Descriptions of other measures can be used in other international regions, for example, to take information from distant databases of global significance, or to provide information on email in the meantime, send a fax.

Global Measures

The processing of data is not centralized, but the shards left from the fret of the central computer can be brought to waste important information otherwise, paralyzed the robot of the fence for some hour. To this end, the need for decentralized processing of information in the measure. The development of benefits and methods of transmission on a large scale has enabled the emergence of global networks. The idea of ​​their encouragement lies in the fact that turn on the computer they can relate to each other and can exchange information on a transcontinental scale.

Servers and global measures are given to other computers, we register on them, access not only to their own resources (information and software, electronic mail, computer conferences), but also to the resources of other servers in the measure, and to secure their ability to work between robots your computer, providing access to the resources of remote machines.

For the rest of the world, the global networks united among themselves, and so the Internet is called. Internet correspondents can know everything in this world that they don’t care about. These files, images, sounds, created in different computer environments and like in file archives of servers. You can copy it on your computer and use it for additional programs, de stink created. From the Internet, you can receive information that changes daily: weather forecasts, exchange rates, statistical information, theater repertoire and restaurant menus, be it programs, etc.

Remote access (access to information from great stani at least) allows you to organize training for any kind of distance (remote training). For example, you can conduct a lesson one hour at different schools of the world, communicating without intermediary with the skin present at such a lesson, or you can organize lectures by professors for a wide range of hearing people from different countries of the world. Zv'yazok z vіdrivom rob with real consultations of the great fakhіvtsіv pіd hіrgіchіchіh opperаcii, konsilіumіv, demonstratsіy tsіkh operіtsіy na navchannya medical personnel.

Particularly noteworthy is the choice of global media in connection with the development of multimedia tools, such as graphics, video and sound support. Documents that contain such components have become the most popular among the available information on the Internet.

To avoid getting lost in the majestic streams of information, on the servers of the borders there are special poke systems. Look for information, and analyze that data of the Koristuvachev for your request, the address of the necessary information.

The global network ensures efficient access to information on a global scale.

Global Merezha - the association of computers, which are distributed in the distant country, for the global selection of light information resources.

Communication channels for exchange of information between computers

The main meta-creation of whether a computer network (local or global) involves secure exchange of information between objects (servers and clients) of a network. It is evident that it is necessary to connect the computers between each other. Therefore, obov'yazykovymi components be-yakoy merezhі є all the channels zv'yazku (providnі and bezdrotovі), for some kind of vicarious different physical media. Vіdpovіdno up to tsgogo in merezhakh razraznyayut such channels zv'yazku, like telephone and fiber optic lines, radio zv'yazok, space zv'yazok and іn.

The purpose of the communication channels in the computer network is easy to understand, as if they were connected by the transport channels of the airline or passenger transport system. Transportation of passengers can be repeated, for help zaliznit abo water (marine chi-river) ways. Choose a car from the middle of transportation. Information is transported through computer networks. Seredovishcha, de vydbuvaetsya zv'yazok komp'yuterі v merezhi, vyznachayut zab'ednannya kom'yuterіv. Yakshcho tse middle, yake vimahaє phone call, Called via telephone cable. Widely zastosovuyutsya z'ednannya computers for additional electrical cables, radio, fiber optic cables too.

All the channels are connected. Call efficiency computer networks isttotno to deposit according to the upcoming main characteristics (parameters) of the channels of the link:

♦ throughput capacity (speed of data transmission), which is determined by the number of bits of information transmitted through the network per second;
♦ nadіynostі - zdatnostі to transmit information without causing costs;
♦ vartosti;
♦ Possibility of expansion (connection of new computers and attachments).

Align the characteristics of the channels with the connection indicated by the table 22.1.

Table 22.1. Characteristics of channels

It can be seen from the table that the electric cable connection can have more throughput building, lower telephone. The table has two types of electric cables. A double-wire cable (or a twisted pair) is cheaper and may be more high security of transmission of data, it is not protected from transmission.

A coaxial (shielded) cable can reduce permeability, but it is one of the most important characteristics. The protection of the crossover will require a wire, so there is a variety of such cables.

The choice of electric cables is much more expensive than the lower telephone channels. Therefore, electric cables are installed like a linking channel on small distances, that is, in local areas. Global networks have a telephone channel for those who have found it. However, there is a low transition to some of the main shortcomings. It can be seen from the table that the best communication channel is a fiber optic cable, which is higher than the highest.

Appointment of lace adapters

For transmission over communication channels, it is necessary to convert computer signals to signals of physical media, so that they can be transmitted by electrical, optical, telephone routes. For example, when transmitting information over a fiber optic cable, the computer data will be converted to optical signals. For this vicory, there are special technical attachments - merezhni adapters.

Merezhevі adapters (merezhnі cards) - technical attachments, scho vykonuyut functions spoluchennya kom'yuterіv іz channels zv'yazku.

Merezhev adapters are connected to the channels of communication. For a dermal view of the channel, a tie requires your own type of lace adapter.

The adapter is inserted at the right socket of the computer's motherboard and connected with a cable from the third adapter of the other computer. The addresses of the computers at the border are displayed on the maps, without which the transfer is impossible. If information circulates through the mesh, the skin of the mesh computer selects data from the global flow that are recognized by you. This choice is valid for the address of the computer.

It is also necessary to use software to set the mere addresses of computers. A large number of special mesh system casings have been disassembled. These allow you to specify the addresses of computers, to request the number of koristuvachіv merezhі, as if the border is fenced for the number of clients, to allow or to block access to the catalog or hardware resources for various computers, including the rights to the measure, the possibility of defending information is also transferred. Some catalogs can be made accessible only for reading, others - for reading and writing information, and even if they are in the heat, they can be made inaccessible. At the same time, coristuvachs can see only part of the server information. Merezhev programs allow to press life koristuvacham different access rights. This visit is necessary for the security of information and confidentiality.

Assigned to modem

The peculiarity of the global network is the meaning of the remoteness of computers one kind of one. For their connection, telephone lines and modems are widely used. The telephone line transmits the sounds of human voices (like analog signals). The digital signals from the computer are converted by the modem (module) into signals that can be transmitted over the telephone network, and at the other end of the day they are received by another modem and converted (demodulated) from analog digital signals of the computer.

The modem is an attachment that modulates (changes digital signals in analog) and demodulation (conversion of analog signals to digital).

The modem is connected to the computer from the telephone line. For robots with it, a special control program - the modem driver - can be captured in the operational memory. Z її to help carry out the adjustment of the relevant parameters of the modem (installation of the modem), without which the robot will work with it, and therefore, communication from the network of impossibility.

On the other end of the telephone line, you can also connect a modem, connect to another computer. If the receiver computer is able to receive signals from the network, then the modem will be replaced by the network adapter in the global network. If the computer is a client, then the vin can be assigned to the address of the computer, which vin is sent to the server. Qi installations are counted for the hour of adjusting the protocol and software security.

Modems are calling (they are connected to system unit through the last port) and internal (at the sight of the payment, which is installed at the nest of the mother board). The stench is distributed with the maximum speed of transmission.

Expanded at the same time the middle of the koristuvachіv modem mаyut shvidkostі 28800, 33600, 56 TOV bіt per second. Also available are more modems high swedishness exchange.

The shards of modems are replaced by the yard adapters at the yards, the telephone lines can serve as communication channels, they can be stuck on such yards of the yard, which are slandered by great lines. As soon as the modem vikoristovuvatime trivalo work at the merezhі, you happen to take a telephone channel. The call on the telephone channels is undesirable, and, moreover, the speed of its transmission is not as high as it is on cables. Therefore, in the local connections for the connection, it is customary to twist the electric cables.

The role of protocols in the exchange of information among companies

In order for the information, transmitted by one computer, to be understood by another computer after it was omitted, it was necessary to develop a single transmission rule in the ranks of protocols. During the development, all communication problems were covered and standard information delivery algorithms were vibrated.

In case of any transportation, it is necessary to strictly follow the rules. What are the rules, for example, about how to get rid of passengers on trains? Passengers buy tickets and borrow money assigned to them. Otherwise, the carriages will start to move without a lot of passengers, like they want to take a better job. The passenger does not have the right to carry tigers, bears and other wild creatures with him. For the transportation of your creatures, you have your own rules. Conductor of goiter guards behind the sanitary station of the car and the sanitary unit, obviously drive, otherwise the passengers can come to the station sick. The pull follows the layout, the teeth are necessary. When moving to European lands, the wagons are replaced with wheels for the passage of narrow-gauge gauges (also trains from rails). Bachite, like a lot of everything you need to transfer for an hour of transportation. The same when transmitting information.

True, the transfer of data is a foldable process, and it can be seen on different levels. We do not discuss everything in public. Prote torknemosya deyaky pitan.

The transfer protocol is set to suit the needs of computers that interact. In order to establish a connection between computers, it is necessary to enter their addresses. Qi addresses are assigned by intermediary adapters, telephone numbers and call programs. The rules for clearing the address of computers in the global network of faults are absolutely the same, regardless of those computers in the network can be different and victorious for different operating systems.

The transfer of data in one rich stream can lead to waste or creation. That's why the stench is divided into blocks (packages) of information about the song's history. The skin of such a block is accompanied by service information, including the recognition signs of the first cob and the beginning. Transfer protocols to replace the mechanism of recognition of the cob and the end of the block. The stench is to manage the flow of data, to spread it, to vibuduate from the devil. For the rest of the world, the receiver of information is to blame for the rules (protocols) themselves. Only one computer can understand what is being transmitted one to one.

The skin of the package will take the number, in order to recognize the pardon, or to spend the first hour of contacting the information, and also to re-energize the same package, to overcome such a winickly problem. You can match the transfer of these packages with the delivery of parcels by mail in the same screenshots and standard addresses. Aje skin dressing is also accompanied by service information. If you want to give you a little parcel and one of them didn’t come, you can ask for it, obviously.

At the link with the numerical orders, yakі may virishuvatisya standard rank, razraznyayut different mind protocols for the transfer of data, correction and correction of pardons and in.

At the edge of the Internet there is an international protocol TCP / IP, creations at the rocky. Mere management is decentralized. Tse means that out of harmony with any node (computer) of the network, the functioning of other computers is saved. Data packets are transferred as soon as possible to the computer with the required address, and in case of a faulty accident on one of the computers, they are automatically forced by another route. For the owner, it is not important, which route of that chi іnshiy package will reach the new one. In the city of recognition, the stench will come together in one place. So packages can reach the addressee and bypass routes.

Control nutrition and task

1. How do you see the line?

2. What is the recognition of a dermal appearance of a merez?

3. How do the terminals and the central machine look like computer networks?

4. What is called a client, what is a server?

5. Designate a variety of local measurements.

6. Designate a common corporate measure.

7. Choose the best global measure.

8. Name the main types of communication channels.

9. What is covered during the organization of the measure?

10. How to connect computers in one place?

11. Designate an hour for each transfer of a 6 MB file over coaxial cable9 over a telephone line over fiber optic cable.

12. Why are telephone lines broken in computer networks?

13. What is a lace card?

14. What is a modem? How do you use modems?

15. What are adapters and modems for?

16. Describe the functions and characteristics of modems.

17. Why would you want to buy modems with more transmission speed?

18. What is the best way to use a modem, and what is a network adapter for organizing a network?

19. What is called a protocol? Tell me about the functions of the transfer protocols.

Subject

• Hardware and software security.

Tsіl

• Learn about attachments and software tools, for the help of which the computer network is being created.

Hid lesson

For creation and functioning computer mesh you need special attachments and software tools. Up to the apparatus part for the folding of the barriers can be seen lace adapter, fencing cable, modem, router and host computer– the annexes themselves allow organizing a local network and the possibility of access to Internet.

Host

Basic technical buildingє special computer, which ensures the safety of informational functions. Such a machine is called a host - a computer - it is the fault of the host to change it at the switched on station, data transmission according to measure.

All other computers are required to be connected to the host machine. Adzhe leather coristuvach, which works in the middle of the merezhі, for any furnishing of vikoristuvach resource.

For the help of Ethernet - the equipment of the machine is connected one to one. Such a system is composed of such elements as a cable (vita pair), special roses and mesh adapters. The cable is twisted when transmitting and receiving information between working stations.

To connect the cable with roses, which are connected through T-conectory to merezhnyh adapters - special interfacing boards . They can either be integrated or plugged into the expansion slot of the computer's motherboard.

Routers required for connection to the open circuits of the city.

Cables are twisted for Ethernet equipment different types. Tse and coaxial cables (coax) and cables to the type of torsion of the bet. The dermal type cable needs a different rose and a water connection to lace card. Also, it should be noted that the coaxial type of connection is already a little deficient due to its correct portability and inappropriate connection. The characteristics of the wire are changed in the fall of the cable - the length of the cable is maximum number working stations that are connected to the new one.

The speed of transmission in the Ethernet network is close to 100 Mb/s.

To connect a computer with telephone line(through a connection to the Global Network), it is necessary for the mother special attachment – modem (MO dulyator - DIM odulator).

Modulation- The process of converting digital form and transferring information to analog.

Demodulation- a return to the recipient of information. Modems are both external and internal. The external modem is an add-on that connects to a PC via a COM port (connected to a skin computer), an internal modem is an electronic board that can be installed in the middle of the system unit.

One of the important characteristics of a modem is the speed of transmission (Kbps). Older modems may have a connection speed of 36 Kb/s, modern ones have a higher connection speed - 128 - 256 Kb/s just.

Merezhevy adapter

Merezheva card is a fee that is inserted into motherboard PC. Vaughn, like and impersonal other outbuildings can be integrated into the "motherboard". Merezhevі adapters є devices for receiving / transmitting data and are used for connecting work stations not only among themselves, but also between the host computer and the router for access to Internet.

Software security measures

Before |programming problems the functioning of the measure can be seen such components as Merzhevі operating systems Merzhevі programs(Browsers, etc.).

Merezheva operating system

Merezheva operating system- Tse the basis of the foundations be-like a merezhі. It is needed for handling by received/transmitted notifications between servers and working stations. Vaughn also allows any kind of coristuvachev to work with a hard disk or a printer, as it is not physically connected to your computer. Unix ta Microsoft Windows Server 2003 and 2008.

At the fences operating system, installed on a desktop PC, you can see the following characteristics:

• PC resource management (rozpodil operational memory, management peripheral buildings and other functions
• nadannya vlasnyh resursiv for zagalny vykoristannya (rozsharuvannya)
• sobi, for the help of those who need to exchange, that transfer is confirmed at the border.

The fallow of the functions of the computer itself in the same operating system can be either a client or a server part.

Browser (English) Browser) – a software security measure, recognized for the display of web pages written in special languages.

Also, browsers are recruited to promote and promote various content in the Global Merge.

Power supply

1. What is the cost of the hardware part of the service?

2. Do you still need a cross adapter?

3. What is a modem?

4. What are the functions of the operating system?

5. Tell me about browsers.

List of vicorists dzherel

1. Lesson on the topic: "Function of computer systems", Igolkin A.P., m. Makiivka.

2. Morgunov Zh. Ts. Modern computer facilities. - 2008

Edited and added by the contributor of Kievsky national university im. Tarasa Shevchenko Solovyovim M.S.

Practiced over the lesson

Solovyov M. Z.

Igolkin A.P.

APPLICATION AND CLASSIFICATION OF COMPUTER MERGE

Services of the global Internet.

The global network of the Internet. Addressing.

Appointment and classification of computer measurements.

INTERNET TECHNOLOGIES

Plan:

Merezha computer- The system of communication between computers and computer control.

Depending on the territorial distribution of subscriber systems, the number of measures can be divided into three main classes:

Globally counting network (WAN - Wide Area Network)- Tse system of computers united in a merezh, roztashovanih on great vistas one type of one.

Regional counting measure (MAN - Metropolitan Area Network) po'yazuє subscribers, roztashovannyh on a significant vіdstanі one type of one (tens - hundreds of kilometers).

Local counting network (LAN, LAN - Local Area Network) united subscribers, distribution at the borders of a small territory (2 - 2.5 km).

Hardware security of the local counting system, including workstations, server, communications.

Working station- a personal computer, connections to the merezhі and secures the access of the coristuvach to її resources.

Server – specialization computer at the merezhі, appointments for vikonannya on the new service software.

For connection of a working station from a channel, the connection is made lace adapter.

Communication channel in the computer network- Tse physical medium of transmission of information.

The communication channels are divided into three main capacities: building capacity, security, price.

Throughput capacity - the maximum speed of transmission over the channel. Sounds out in kilobits per second (Kbps) or megabits per second (Mbps).

Let's look at the channel zv'azku.

Twisted couple characterized by a nasty shift and low speed of information transfer 0.25 - 1 Mbit / s. Low varity.

coaxial cable May have high security and security of data transmission up to 10-50 Mbit/s.

fiber optic cable not weak to di ї elektromagnіtnіh polіv i himself practically can't change. Transmission speed is more than 50 Mbit/s.

Rootless merezhi. Technologies dartless sting computer networks are based on coding and transmission of signals in the form of electromagnetic vibration.

The widest range of transmission standards in the radio range: Bluetooth, Wi-Fi, GPRS, Wi-Max, 3G, LTE.

Establish transmission standards for the light range: infrared - IrDa and others.

Communications:

Merezhevy concentrator or hub– Lease extension, assignments for the integration of a number of Ethernet attachments on the open segment of the fence. Attachments are connected for the help of a twisted bet, coaxial cable or optical fiber.

At this hour, habi mayzhe are not allowed out - they came to change fencing switch(Switches)- outbuildings, designated for the construction of a number of nodes in the merezh in the boundaries of one or more segments in the merezh.

Router (router)– an annex, a kind of bi z'ednannya of administratively independent communications measures.

Mist– tse attachments that connect two lines, that use the same methods of data transmission

Gateway- ce attachments, which allow organizing the exchange of data between two measures, like victorious different protocols of mutual modality.