Driver for a network card: what it is and why it is needed. Wi-Fi network card: types, principle of operation and connection

Network cards are an external device and the computer system unit are installed as an additional extension. In general, this is reflected in the name itself. PCI network cards should be mentioned at the beginning of the conversation. This indicates the interconnection of peripheral components. Peripheral Component Interconnect means data input/output bus. Peripheral devices connected to the motherboard use this bus. These cards are connected using a PCI connector. They are clearly visible in the photo below.

This PCI interface is interesting because its throughput is peak. It corresponds to the 32-bit variant, which operates at a frequency exceeding 33 MHz and at a speed of 133 MB/second. The voltage used is up to 5 V. PCI is used to connect expansion cards, for example, a modem, video capture cards, network adapters and much more.

But what exactly can be installed there? Adapters cost about five or six dollars.

Other adapters can organize a wireless network - WI-FI.

That is, devices that perform different functions can be connected to the same interface.

But gradually this interface is losing popularity among developers, and network cards are also being modernized. Now network cards have the Pci Express 1X form factor.

But there are also built-in network cards. They are integrated into the motherboard. If there is a hole on the back of the system unit, highlighted in the picture with a red line, then you have a built-in network card.

This is the output of the network card and visually we can verify its presence.

Signal lights

There are usually information LEDs nearby. They are located near the twisted pair connector. These diodes also indicate whether there is a network and whether there is a connection to it.

In addition, these same diodes can signal the operating status of the device. That is, if the same twisted pair or network cable is connected, then the LED will blink, and it blinks rhythmically, just like information data packets arrive.

If the network adapter is not working, the indicators may show other signals. For example,

• The LED does not blink, but is constantly on,
• blinks, but the rhythm is monotonous,
• doesn't light up at all.

You need to know about this in order to observe and notice problems in time. Not only life consists of little things, but also the work of a computer.

Let's see what the built-in network card looks like when the case cover is opened. We find a familiar connector and a chip not far from it. It is soldered onto the motherboard and it performs the function of a network adapter.

It must be said that integrated network cards are not a reliable device. Very often they fail. And this happens with enviable regularity even on new computers. Therefore, all attention switches to the external network card.

Let's look at the connectors

Here's a new photo below. Look carefully, this is the network card connector. Can you see the difference?

The difference is that there are eight contact pads on one side and only four on the other. But both cards are capable of a data transfer speed of one hundred megabits/second.

But how so? Something's wrong here

Then let's take a look at the twisted pair cable that we've mentioned so many times. This is a cable and we have already laid a network with its help.

To put it correctly, this is a UTP cable. From English Unshielded Twisted Pair is translated as unshielded twisted pair. Twisted means twisted. This is clearly visible in the photograph. Twisting the conductors provides interference protection throughout the entire cable.

The veins do not have any additional braiding, and that is why the word “unshielded” appeared. And this makes the cable better protected. All conductors included in the cable are twisted in twos, which is why we are talking about a pair. All pairs vary in color. There is white-green - green, white-orange - orange, white-blue - blue, white-brown - brown.

But these pairs, four in number, are not used immediately when transmitting data at a speed of 100 megabits/second. As you guessed, the number eight appears here. But for the mentioned speed, two pairs, that is, four veins, are enough. But what kind of wiring will be used is strictly defined. These are postings numbered 1,2,3 and 6.

This is what these wires look like in an RJ-45 connector.

These numbers correspond to pairs of green and orange. Of course, color here plays only a symbolic role. If you have a different color at numbers 1,2, 3 and 6, then so be it. But the order must be strictly maintained, then the speed will correspond to 100 megabits/second.

Now look again at the network card connectors. This is the photo above. Where there are only four sites, look what they are like. You can easily guess that these are the first, second, third and sixth sites.

But then the question arises: why are there eight wires and when can they all be used? Answer: They will be used at a data transfer rate of one gigabyte/second. And at higher rates, all eight wires are used.

But let's return to the network card. We've already talked about what they are, but we'll talk more.

So, what network cards are there?

For example, let's take a network card for a laptop. Its standard is PCMCIA. Since this is an external board, we will connect it to a special connector. The PCMCIA standard or Personal Computer Memory Card International Association is translated as the international association of computer cards. At first it was used in the production of expansion cards. Now you can connect other peripheral devices, such as network cards, hard drives or modems.

Built-in card replacements

If the built-in card in a laptop suddenly fails, then there is no need to bite your elbows; in the photo below you see an excellent solution to the problem.

Or this is a solution, this device will be useful not only for a laptop, but also for a desktop PC.

These devices are called “USB network cards”. Despite the decision of the external design, their essence as a whole does not change. Other examples of devices can be seen below.

It's too early to say goodbye

We could have ended it here. But no. After all, external network cards are so diverse that it’s worth talking about more.

There is such a type of network card as a server one. It can only be used in advanced and high-performance systems. Of course, we compare it with a regular network adapter. They still have a standard interface. This is enhanced PCI-X or regular PCI.

The picture below shows an example of a server network card.

It is clearly visible that there are four network adapters here. But they are all in one device. And each connector has its own twelve-digit identifier, that is, a MAC address. Although one IP address can be assigned for the entire group of adapters. And the operating system perceives this group of cards as a single whole.

What is a MAC address? This, Media Access Control, translates as media access control. An address is always unique and, of course, there cannot be two identical addresses.

Port aggregation is not easy, and it is possible thanks to Port Aggregation technology. The name stands for the association. And this means that several network segments can be combined into one. This increases productivity. Well, accordingly, when all network pots are combined into one, then we are talking about the performance of one, that is, a single port. And its power is equal to the number multiplied by the number of these ports.

There are two modes for operation of server network cards. Let's get to know them now. Each card comes with software included. With its help, each of the present ports can be made active or standby.

There is also a mode when network traffic is distributed evenly across active segments. This is a distribution mode and it allows you to reduce the overall load on the adapter. In recovery mode, when the connection suddenly disappears, it restores. That is, the mode ensures uninterrupted communication between the network and the card.

Is it convenient to use the server card on a computer?

It all depends on how complex your PC is. If there are a lot of bells and whistles, then, in order not to load the central processor, the server card can take on some of the functions, for example, counting the sums of data frames. This data is transmitted over the network. It can also generate data.

Network card, also known as a network card, network adapter, Ethernet adapter, NIC (English network interface card) is a peripheral device that allows a computer to communicate with other devices on the network. Nowadays, especially in personal computers, network cards are quite often integrated into motherboards for convenience and to reduce the cost of the entire computer as a whole.

Types

Based on their design, network cards are divided into:

• internal - separate cards inserted into an ISA, PCI or PCI-E slot;

• external, connected via USB or PCMCIA interface, mainly used in laptops;

• * built into the motherboard.

On 10-megabit network cards, 3 types of connectors are used to connect to the local network:

• 8P8C for twisted pair;

• BNC connector for thin coaxial cable;

• 15-pin transceiver AUI connector for thick coaxial cable.

• optical connector (en:10BASE-FL and other 10 Mbit Ethernet standards)

These connectors can be present in different combinations, sometimes even all three at once, but only one of them is working at any given time.

On 100 Mbit boards, either a twisted pair connector (8P8C, erroneously called RJ-45) or an optical connector (SC, ST, MIC) is installed.

One or more information LEDs are installed next to the twisted pair connector, indicating the presence of a connection and the transfer of information.

One of the first mass-produced network cards was the NE1000/NE2000 series from Novell with a BNC connector.

Network adapter settings

When configuring a network adapter card, the following options may be available:

• hardware interrupt request line number IRQ

• DMA channel number (if supported)

• base I/O address

• RAM memory base address (if used)

• support for auto-negotiation duplex/half-duplex standards, speed

• support for tagged VLAN packets (802.1q) with the ability to filter packets of a given VLAN ID

• WOL (Wake-on-LAN) parameters

• Auto-MDI/MDI-X function automatic selection of operating mode for straight or cross-crimped twisted pair

Depending on the power and complexity of the network card, it can implement computing functions (mainly counting and generating frame checksums) either in hardware or software (by a network card driver using a central processor).

Server network cards can be supplied with two (or more) network connectors. Some network cards (built into the motherboard) also provide firewall functionality (eg nforce).

Functions and characteristics of network adapters

The network adapter (Network Interface Card (or Controller), NIC) together with its driver implements the second, channel level of the open systems model in the final node of the network - the computer. More precisely, in a network operating system, the adapter and driver pair performs only the functions of the physical and MAC layers, while the LLC layer is usually implemented by an operating system module that is common to all drivers and network adapters. Actually, this is how it should be in accordance with the IEEE 802 protocol stack model. For example, in Windows NT, the LLC level is implemented in the NDIS module, common to all network adapter drivers, regardless of what technology the driver supports.

The network adapter together with the driver performs two operations: frame transmission and reception. Transmitting a frame from a computer to a cable consists of the following steps (some may be missing, depending on the encoding methods adopted):

• Design of the MAC layer data frame into which the LLC frame is encapsulated (with flags 01111110 discarded). Filling the destination and source addresses, calculating the checksum. Receiving the LLC data frame through the cross-layer interface along with the MAC layer address information. Typically, communication between protocols within a computer occurs through buffers located in RAM. Data for transmission to the network is placed in these buffers by upper-layer protocols, which retrieve them from disk memory or from the file cache using the operating system's I/O subsystem.

• Formation of code symbols when using redundant codes of type 4B/5B. Scrambling codes to obtain a more uniform spectrum of signals. This stage is not used in all protocols - for example, 10 Mbit/s Ethernet technology does without it.

• Output of signals into the cable in accordance with the accepted linear code - Manchester, NRZ1. MLT-3, etc.

Receiving signals from the cable that encode the bit stream. Receiving a frame from the cable to the computer involves the following steps:

• Isolating signals from noise. This operation can be performed by various specialized chips or DSP signal processors. As a result, a certain bit sequence is formed in the adapter receiver, which with a high degree of probability coincides with the one sent by the transmitter.

• If the data was scrambled before being sent to the cable, it is passed through a descrambler, after which the code symbols sent by the transmitter are restored in the adapter.

• Checking the frame checksum. If it is incorrect, the frame is discarded, and the corresponding error code is sent to the LLC protocol through the inter-layer interface to the top. If the checksum is correct, then an LLC frame is extracted from the MAC frame and transmitted through the cross-layer interface upward to the LLC protocol. The LLC frame is placed in a RAM buffer.

The distribution of responsibilities between a network adapter and its driver is not defined by standards, so each manufacturer decides this issue independently. Typically, network adapters are divided into adapters for client computers and adapters for servers.

In adapters for client computers, a significant part of the work is shifted to the driver, thereby making the adapter simpler and cheaper. The disadvantage of this approach is the high degree of load on the computer's central processor with routine work on transferring frames from the computer's RAM to the network. The central processor is forced to do this work instead of performing the user's application tasks.

Therefore, adapters designed for servers are usually equipped with their own processors, which independently perform most of the work of transferring frames from RAM to the network and vice versa. An example of such an adapter is the SMC EtherPower network adapter with an integrated Intel i960 processor.

Depending on which protocol the adapter implements, adapters are divided into Ethernet adapters, Token Ring adapters, FDDI adapters, etc. Since the Fast Ethernet protocol allows, through the auto-negotiation procedure, to automatically select the operating speed of the network adapter depending on the capabilities hub, many Ethernet adapters today support two operating speeds and have the prefix 10/100 in their name. Some manufacturers call this property autosensitivity.

The network adapter must be configured before installation in the computer. When configuring an adapter, you typically specify the IRQ number used by the adapter, the DMA channel number (if the adapter supports DMA mode), and the base address of the I/O ports.

If the network adapter, computer hardware, and operating system support the Plug-and-Play standard, then the adapter and its driver are configured automatically. Otherwise, you must first configure the network adapter and then repeat its configuration settings for the driver. In general, the details of the procedure for configuring a network adapter and its driver largely depend on the adapter manufacturer, as well as on the capabilities of the bus for which the adapter is designed.

Classification of network adapters

As an example of adapter classification, we use the 3Com approach. 3Com believes that Ethernet network adapters have gone through three generations of development.

First generation

Adapters first generation were implemented on discrete logic chips, as a result of which they had low reliability. They only had one frame of buffer memory, which resulted in poor adapter performance as all frames were transferred from the computer to the network or from the network to the computer sequentially. In addition, the first generation adapter was configured manually using jumpers. Each type of adapter used its own driver, and the interface between the driver and the network operating system was not standardized.

Second generation

In network adapters second generation To improve performance, they began to use the multi-frame buffering method. In this case, the next frame is loaded from the computer memory into the adapter buffer simultaneously with the transfer of the previous frame to the network. In receive mode, after the adapter has fully received one frame, it can begin transmitting this frame from the buffer to the computer's memory simultaneously with receiving another frame from the network.

Second-generation network adapters widely use highly integrated circuits, which increases the reliability of the adapters. Additionally, the drivers for these adapters are based on standard specifications. Second-generation adapters typically come with drivers that run on both the NDIS (Network Driver Interface Specification) standard developed by 3Com and Microsoft and approved by IBM, and the ODI (Open Driver Interface) standard developed by Novell.

Third generation

In network adapters third generation(3Com includes its adapters of the EtherLink III family) a pipeline frame processing scheme is implemented. It lies in the fact that the processes of receiving a frame from the computer’s RAM and transmitting it to the network are combined in time. Thus, after receiving the first few bytes of the frame, their transmission begins. This significantly (by 25-55%) increases the performance of the “RAM - adapter - physical channel - adapter - RAM” chain. This scheme is very sensitive to the transmission start threshold, that is, to the number of frame bytes that are loaded into the adapter buffer before transmission to the network begins. The third generation network adapter performs self-tuning of this parameter by analyzing the operating environment, as well as by calculation, without the participation of the network administrator. Bootstrapping provides the best possible performance for a particular combination of the performance of the computer's internal bus, its interrupt system, and its DMA system.

Third-generation adapters are based on application-specific integrated circuits (ASICs), which improves adapter performance and reliability while reducing its cost. 3Com called its frame pipeline technology Parallel Tasking, and other companies have also implemented similar schemes in their adapters. Increasing the performance of the adapter-memory channel is very important for improving the performance of the network as a whole, since the performance of a complex frame processing route, including, for example, hubs, switches, routers, global communication links, etc., is always determined by the performance of the slowest element of this route. Therefore, if the network adapter of the server or client computer is slow, no fast switches will be able to increase the speed of the network.

Network adapters produced today can be classified as fourth generation. These adapters necessarily include an ASIC that performs MAC-level functions (MAC-PHY), speeds up to 1 Gbit/sec, as well as a large number of high-level functions. The set of such functions may include support for the RMON remote monitoring agent, a frame prioritization scheme, functions for remote computer control, etc. In server versions of adapters, it is almost necessary to have a powerful processor that offloads the central processor. An example of a fourth generation network adapter is the 3Com Fast EtherLink XL 10/100 adapter.

Network card for computer- This is part of the PC hardware configuration. This device will allow you to connect a personal computer or laptop to networks of any size and ensure interaction with them. Network card for computer, Usually called an Ethernet card, it also has an alternative name - network interface cards (NIC), network adapter or LAN adapter.

Standard Components

Network card for computer At first it was one of the components of an add-on, which can be purchased and installed on a computer not immediately with all the components, but after some time when the need arises. But today it has become obvious that network card for computer becomes one of the standard components that are installed in the absolute number of all produced desktop computers, laptops and NET-books. Network cards are integrated into a large number of modern motherboards and other devices during the initial manufacturing process. If network card for computer was installed in the system when assembling the system unit, then when connected to the local network it will reveal itself with small flickering indicators located near the network connector on the rear wall of the system unit.

Network Card Identification

Absolutely every one network card for computer must be unique and for all this it is routinely equipped with a so-called “media access control” address, or otherwise known as a MAC, which helps identify each computer transmitting data packets through the network. This address is a 48-bit digital-character sequence that is installed using the firmware method into the chip's read-only memory (ROM) soldered onto the network board. The first row is the 24 bits of the MAC address and is called the group unique identifier “organizationally unique identifier” or OUI. Typically the MAC address is tied to the manufacturer of the network card. Subsequently, it can be replaced with another using MAC spoofing technology.

OSI model

The network card operates mutually at two levels of the open systems interaction model or another OSI. The first level, as a rule, is the physical level, which quite naturally determines the fact that network card for computer can provide physical access to the network. A network card for a computer can also operate at the second level of the OSI model, which is called the data link layer and is responsible for addressing. The main task of addressing using these two layers is to encode the MAC address into the data packets sent by each network card on any computer.

Types of network cards

Today, network cards can connect their computers both via a cable (physical) connection and via a wireless interface. When connecting via cable, a standard network port with an RJ-45 connector is usually used. A wireless network connection does not require the use of any physical ports or interfaces.

Characteristics and capabilities of network cards

Both types of network cards, wired and wireless, currently allow approximately the same data transfer speed. It typically ranges from 10 megabits per second to 1000 megabits per second (Mbps), depending on the manufacturer and model. Also, network card for computer serves to connect to the Internet, again via network protocols. , You can find out by following the link.

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A network card driver is an important component of the operating system. It allows the computer to exchange data with other similar devices. The article we bring to your attention describes in detail the installation procedure for this software, as well as its configuration. All this will allow you to easily connect your computer to a computer network and start exchanging data with other similar devices and more.

What is it and why is it needed?

A driver for a network card is a special program that is part of the operating system. It controls the operation of this particular device. Without installing this software, the operating system will identify it as an “unknown device”. And the adapter itself will not fully function. Therefore, the installation of this software is very important and relevant. The problem is solved as follows:

• Determine the type of network card installed on the computer.
• Find the driver and install it.
• Set the network connection settings.
• We carry out visual inspection and performance testing.

It is in connection with this algorithm that the installation of adapter drivers will be described in the future.

Types of network cards

According to the installation method, such adapters can be soldered to the motherboard (they are sometimes also called integrated), internal (installed inside the system unit) and external (connected to external connectors of a personal computer). In the first case, this is a microcircuit with connectors that are located on the main board of a personal computer. It is in this design that such devices can most often be found today. The second version of the network adapter can be seen much less often in practice. This is a separate board that is installed in the PCI expansion slot of the motherboard. And in the latter case, such a component of a computer system resembles a flash drive that is connected to the USB universal serial bus port. The second classification of such devices is based on the method of data transmission. The first one is wired. That is, information is transmitted using twisted pair cables. The second one is wireless. In this case, electromagnetic radiation is used, and information is transmitted using the Wi-Fi standard.

Plug and Play

On the most popular and most common models, the driver for the network card is installed automatically when installing the operating system. This can be checked as follows:

• Place the mouse pointer over the “My Computer” shortcut (it can also be found in the “Start” menu). Right-click on it to bring up the menu.
• In the list that appears, select “Properties”.
• Next, in the left column, select “Device Manager”.
• In the window that opens, pay attention to two sections. The first one is network adapters. It must contain all devices of this class. Then expand the “Unknown devices” section (if there is one) and move on to the next paragraph of this article. If this section is missing, then you can immediately begin setting up the adapter, since all the necessary software for its full functioning has already been installed.

Determining the installed network card

If the adapter came with a CD and it is available, then we proceed directly to the installation. First, we study the documentation for the personal computer. It must indicate the manufacturer and model of the adapter. If the documentation is irretrievably lost, you can use specialized software, for example, AIDA 64. Download this utility and install it. After startup, we look at the hardware configuration and find out which adapter is installed in the computer system. The next step is to download the adapter driver from the manufacturer’s official website. All other sources cannot be used, since you can download the wrong software from them.

Installing drivers

Next, the driver, which was downloaded from the Internet or is on a CD, must be installed on the computer. To do this, launch its installation version. Then, following the instructions, install this software on your local computer. At the end of this operation, it is recommended to restart the PC.

Another solution

The previously described manipulations can be made much simpler. To do this, just download the DriverPackSolution program and run it. Then it will scan the list of equipment installed on the computer and update all software of that class. The advantage of such a solution is obvious - minimal user participation in the process. But the disadvantage is that the DriverPackSolution utility takes up a lot of space and takes a long time to download. It contains a driver for each Realtek network card model. The situation is exactly the same with equipment from other manufacturers. As a result, its size today is more than 7 GB.

Setting up a network connection

At the next stage, after the Realtek network card driver has been installed, you need to configure the connection parameters. All required values ​​must be specified in the contract that you entered into with the provider. Next, go to “Start”, then select “Control Panel” and find “Network Center”. Then in the right column, click on the line “Change adapter settings”. A window will open containing all the network cards of this personal computer. Open the properties of the custom adapter by double-clicking on its icon. In the window that opens, we gradually expand the configurations for each of the parameters using the same action. Then enter the values ​​and save them. Usually it is enough to configure only 2 parameters: “Internet Protocol version 6” and “Internet Protocol version 4”. This is where the PC network addresses and DNS are set. This information, as noted earlier, must be provided by the provider. By default, the system is configured to automatically accept these parameters.

Visual functional check

Any network adapter is equipped with indicator lights. After correctly installing the software and setting up the network connection, one of them should definitely work. As a rule, this is a green LED that blinks periodically. It is usually located next to the twisted pair connection (for internal and integrated adapters) or on top of the flash drive (for external devices). If this is all true, then we proceed to the next stage.

Due diligence

The last step is to perform a comprehensive connection check. To do this, you need to find out the IP address of the network router or another computer on the local network. You can obtain this information from your system administrator. Home routers have the address “192.168.1.1”. Using his example, we will consider a comprehensive check of connection to a local area network. Press the key combination “Win” (it shows the Windows logo) and “R”. The Run window will open. In its field, enter the command “CMD” and press “Enter”. A command prompt window will open. You need to type the following command into it: “ping 192.168.1.1”. As it is not difficult to understand, the last 4 digits are the address of the computer on the network. In response, connection testing will begin. Based on its results, a message will be displayed with the number of packets sent and received in response. If the quantity is equal, then everything is fine. Otherwise, check the network connection settings. Then, if our PC is connected to the Internet, we can launch a browser, enter the address of any portal (for example, rambler.ru) into it and press “Enter”. After this it should open.

Finally

A driver for a network card is that part of the operating system, without which it is difficult to imagine its full functioning today. Within the framework of this article, the process of its installation, configuration and testing was described in detail and step by step. There is nothing complicated in this operation, so feel free to take it and do it.

Let's touch on a topic like the network card of our computer. Let's start with the fact that network cards are different and may differ both in the range of tasks they solve and in the form factor (appearance). The network card is also often called (Ethernet controller, network or NIC (Network Interface Card) adapter).

First of all, let's divide network cards into two large groups:

• External network cards
• Built-in or integrated (onboard)

Let's start with the external ones. From the name itself it follows that network cards of this type are installed into the computer additionally (with a separate expansion card) or as another external device.

First, let's talk about PCI network cards. The abbreviation stands for (Peripheral Component Interconnect) - the interconnection of peripheral components or - an input-output bus for connecting peripheral devices to. These cards are called that because they are installed in one of the PCI slots (connectors). Here they are, in fact:

The PCI interface itself has a peak throughput for the 32-bit version, operating at a frequency of 33.33 MHz at 133 MB/s, the connector voltage consumption is 3.3 or 5V. Serves for installing additional expansion cards into the computer (old video cards, modems, network adapters, TV tuners, various video capture and video conversion cards, etc.).

So, what network cards are installed there? And here are the most common dollars for five or six:

There are adapters of another type - Wi-Fi (for organizing wireless networks).

As you can see, the connection interface is the same (PCI), but the operating principle is different.

Now, due to the gradual “withering away” of this interface, network cards of the “Pci Express 1X” form factor are being produced.

This applies to external network cards. There are also built-in (integrated into the motherboard) cards. You can determine the presence of a built-in network by looking at the back wall of the system unit.

Here we can visually observe the output of the integrated network card. One or more information LEDs are installed next to the twisted pair connector, which can be used to indicate the presence of a connection and the general activity of the network.

By the way, using these LEDs you can indirectly get an idea of ​​the performance of the device. Let me explain my idea: when the computer is turned on and the network cable (twisted pair) is connected to the card, the LED on it blinks, as they say, in time with the reception (transmission) of information data packets by the adapter to the network.

If the network adapter is not working, the indicators may behave as follows:

1. None of the LEDs light up at all
2. The LED is constantly "on" (not blinking)
3. The indicator blinks, but absolutely monotonously. The period and amplitude of this “blinking” are the same throughout the entire time

So - take note of such moments. Everything is in the details! :)

From the markings we see that this is an RTL chip (from Realtek) with number 8211BL.

Notes e: built-in solutions, unfortunately, are not reliable. In our organization, for example, failures of integrated network cards happen regularly. I can’t say that often, but consistently. By the way, my work computer (bought half a year ago) literally burned out the network card the other day, which once again strengthened my opinion about the unreliability of integrated components. I had to install an external one.

I want you to take a close look at the following photo:

Here we look inside the network card connector. Do you notice the difference? One connector (on the right in the photo) has four contact pads, and the other (on the left) has eight. Moreover, both cards are designed for network transmission speeds of 100 megabits per second.

What's the catch here? And he, in any case, is present here :) Let's remember what the twisted pair cable itself looks like, with the help of which we laid networks in one of our free lessons.

It is correctly called UTP cable (Unshielded Twisted Pair - unshielded twisted pair). The fact that it is twisted (twisted) we can clearly see from the photo above. Its individual conductors are wrapped around each other to improve the noise immunity of the entire cable as a whole.

The designation “unshielded” means that there is no additional protective shield (braid) made of foil or metal over the veins. Again - for better cable protection. And “pair” because the conductors in the cable are twisted in pairs and according to color (white-orange - orange, white-green - green, white-brown - brown, white-blue - blue).

Now - the most important: to ensure data transmission over a network at a speed of 100 megabits per second, you do not need to use all four pairs (eight conductor cores), two pairs (four cores) are enough! Moreover, strictly defined numbers are used: first, second, third And sixth postings

Directly from the RJ-45 connector it looks like this:

According to the above, to ensure a speed of 100 megabits, we use “veins” numbered 1, 2, 3 and 6. Look at the figure above. These are two pairs: orange and green.

Note: Naturally, it is up to us to decide which cores to use when terminating the cable. The main thing to remember is that these should be the 1st, 2nd, 3rd and 6th conductor (for networks with a transmission speed of 100 megabits/s).

Now look again at the photo, which shows a close-up of the computer’s network card connectors. In the right image there are only four contact pads: the first, second, third, the next two are skipped and then... which one? That's right - sixth! :)

When are all eight sites used? In networks with transmission speeds of one Gibabit per second (and higher). This is where all the conductors of the network cable are used to their fullest :)

So, for some reason you and I (or rather, I alone :)) “veered” away from the main topic. What other network cards are there? Let's look at an external adapter for a laptop based on the PCMCIA standard. This is an external expansion card that is inserted into the appropriate slot.

PCMCIA stands for Personal Computer Memory Card International Association. Initially, the standard was developed for memory expansion cards. After some time, the specification was expanded and it became possible to use “PCMCIA” to connect various peripheral devices. As a rule, network cards, modems or hard drives are connected through it.

Imagine an unpleasant picture: your laptop (to the left three times) the card built into it has failed. What to do? The solution is in the photo below:

There are, however, other solutions that are suitable not only for mobile computers, but also for stationary ones. These are USB network cards.

They can be made in different ways, but the principle of their operation does not change. Here, for example, are two such devices in the photo below:

Or even like this, more like a flash drive :)

I was about to end the article here, but... changed my mind! :) I also wanted to tell you about a type of external network cards called server network cards, which are used in high-performance systems and have more advanced (compared to conventional adapters) networking capabilities.

As a rule, they have a standard connection interface - PCI (or its extended version - PCI-X). Here, for example, is a server network card " D-Link DFE-580TX».

As you can see, these are essentially four network adapters combined into one physical device. Each of the four network ports (cards) has its own MAC address (a unique 12-digit physical identifier of any card or other network device). At the same time, the entire group of ports can be assigned one logical identifier (IP address). For the operating system, a group of such cards looks like one virtual card.

Note: MAC (Media Access Control) address is also often called a physical or hardware address (Hardware Address). For example: the MAC address of my network adapter at work is 00-1B-11-B3-C8-82. There cannot be two identical hardware addresses on a network. You can find it out by entering on the command line: ipconfig /all or such a wonderful team using the utility of the same name, like getmac. Getmac will show you all the MAC addresses of all network devices installed on your computer in a very convenient and visual form.

Let's continue. Combining several cards into one becomes possible using the “Port Aggregation” technology (aggregation or port consolidation). Port aggregation means combining several network segments into one with greater performance. When several network ports form one virtual one, its throughput (theoretically) is equal to the performance of an individual port, multiplied by their number.

Server network cards can operate in two main modes. Let's take a closer look at them. Using the software that comes with cards of this class, you can configure each port as “active” (load balancing mode) or reserve any ports to ensure fault tolerance (recovery mode).

The network load sharing (distribution) mode evenly passes network traffic (data flow) through active segments, reducing the overall load on the adapter, and the recovery mode (in the event of a physical connection failure) ensures uninterrupted communication between the network card and the network.

What else is good about a server network card on a computer? Depending on its “sophistication” :) it can implement computational functions (counting and generating checksums of data frames transmitted over the network) in hardware, without adding additional load.

On such adapters, specialized LSIs (Large Integrated Circuits) are installed, which take on a significant part of the work (collision detection, assembly and disassembly of data packets, checking frame checksums and retransmitting damaged packets). Thus, as we have already said, a significant part of the load is removed from the processor, which already has something to do in a server system :)

Moreover, expensive server network cards have their own processor installed. Such cards show very good performance, as they can effectively cope even with heavy loads. The presence of its own processor allows you to install up to one megabyte on them. And this already transfers these products from the category of just network cards to the category of communication network processors.

It is also impossible not to note such a useful feature as self-healing drivers for such devices. What it is? For example, after a network failure, the adapter can independently decide to restart the network card driver, enable a network connection integrity check, or even forcefully disable the failed port.