Network card: purpose, classification, basic parameters. Network card on a computer

Network card, also known as network card, network adapter, Ethernet adapter, NIC (network interface card) - a peripheral device that allows the computer to interact with other network devices. Currently, 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 Mbit network cards for connecting to local network 3 types of connectors are used:

• 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)

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

• channel number direct access to DMA memory (if supported)

• base address I/O

• 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 functions firewall(for example, nforce).

Functions and characteristics of network adapters

The network adapter (Network Interface Card (or Controller), NIC) together with its driver implements the second, link layer models open systems at the final node of the network - the computer. More precisely, online 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 to be transmitted to the network is placed in these buffers by protocols upper levels, which extract 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 step is not used in all protocols - for example, Ethernet technology 10 Mbit/s does without it.

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

• Isolating signals from noise. This operation can be performed by various specialized chips or signal DSP 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 checksum is correct, then an LLC frame is extracted from the MAC frame and transmitted through the inter-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 CPU is forced to do this work instead of doing applied problems user.

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 built-in Intel processor i960.

Depending on which protocol the adapter implements, adapters are divided into Ethernet adapters, Token Ring adapters, FDDI adapters, etc. Since the protocol Fast Ethernet allows, through the auto-negotiation procedure, to automatically select the speed of the network adapter depending on the capabilities of the hub, then many Ethernet adapters Today they 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 usually specify the number IRQ interrupts, 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 usually come with drivers that work like the NDIS (NDIS Interface Specification) network driver), developed by 3Com and Microsoft and approved by IBM, and in the ODI standard (interface open driver), developed by Novell.

Third generation

Third generation adapters are based on specialized integrated circuits(ASIC), which increases the performance and reliability of the adapter 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 channels communications, 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 network speed.

Network adapters produced today can be classified as fourth generation. These adapters necessarily include an ASIC that performs the functions of the MAC level (MAC-PHY), the speed is developed up to 1 Gbit/sec, as well as large number high-level functions. These features may include agent support remote monitoring RMON, Frame Prioritization Scheme, Functions remote control computer, etc. B server options adapters are almost a must powerful processor, unloading CPU. Example network adapter fourth generation The 3Com Fast EtherLink XL 10/100 adapter can serve.

A device such as a network card allows a laptop or computer to work on the Internet and local network via WiFi, connected via USB or via a special cable. The adapter provides a unique address called MAC, which identifies the computer device transmitting packets of information over the network. If you cannot connect with a cable, you can purchase a wireless wifi adapter for your computer equipment.

What is a network card

An element of the hardware configuration of a laptop or computer is called a Network interface controller, which provides the ability to connect to a network, ensuring interaction between devices. Network cards are LAN adapters, NICs, Ethernet adapters or interface cards. Now the Network interface controller is part of the computer package, but previously it was produced separately.

Types of network cards

The Ethernet adapter is designed to connect computer devices to the local network. The Network interface controller, which provides an Internet connection, has the main characteristic of data transfer speed. To interface with a computer device, the NIC uses high speed interfaces. There are 4 design types of computer boards. They all have basic pros and cons.

Types into which microcircuits are divided according to their physical implementation:

• integrated - as the name suggests, built into the motherboard;
• wireless – for bluetooth networks and WiFi;
• internal (separate boards) – connected via PCI, inserted into a PCI-E or ISA slot;
• External network cards for laptops are inexpensive and connect via USB.

Why do you need a network card in a computer?

The main purpose of a network card is to connect computer devices with each other. The Ethernet adapter provides connection to the Internet. If there is no built-in Network interface controller, then USB modems are used, but then the ability to work over the network is reduced. By combining computers, laptops, peripherals(scanners, printers, etc.) on the same local network, you can exchange data via WiFi within the boundaries of an apartment, house or provider network.

Operating principle

Some of the functionality of the Network interface controller can be transferred to the central processor or driver. Information is transmitted over the network, which is grouped into data packets. They move from one device to another. There is software and hardware involved in data transfer. NIC refers to hardware. He is responsible for establishing physical connection between devices. An 8-pin RJ-45 or 15-pin AUI connector is used.

Where is the network card located in the computer?

The network card in the computer is located in the system unit. You can find it by slightly opening the side cover of the system unit. Modern computers do with an Ethernet interface. The built-in NIC is soldered onto the motherboard. If it is not built-in, then it is inserted into one of the free white slots. Operation and data transmission is carried out using a cable with optical fiber, connected to the adapter connector.

What does a network card look like?

You can see what a network card looks like in online stores that have photos of devices. Externally, the device looks like a flash drive, and internally it looks like a small chip or board located near the connection connector computer network. It is curved on one side. If you don't open sidebar system unit, the location of the Network interface controller looks like a socket for connecting a cable.

How to find out your computer's network card

In the operating room Windows system It will not be difficult to determine the NIC, which is necessary in case of malfunction or replacement. Programmers call such adapters consumables, because they tend to break. The network card for a PC is an important part of the system configuration, so you can use it to detect it. special programs such as "Everest" and "AIDA64". You can determine the model name yourself by following the path:

1. Start.
2. Control Panel.
3. System and security.
4. System.
5. Device Manager.
6. Network adapters.

How to check if a network card is working properly

A broken network card for a computer or a faulty Wi-Fi card will not allow you to access the Internet or local network. Serviceability problems may be hidden in system settings(if you have a built-in LAN adapter) or in the cable connection density (if external). You can try updating the drivers or testing. The check is carried out in the following way:

1. Computer properties.
2. Device Manager.
3. If there are no exclamation marks next to the name of your adapter, then the equipment is detected normally. Contact your provider.

How to install a network card on a computer

Before you decide to purchase a LAN adapter, you need to make sure that the motherboard does not have its equivalent. The NIC can simply be disabled. To enable it, you need to activate it in basic system input/output (BIOS). If it really doesn’t exist, then buy a NIC at a computer store, and then install and connect the network card:

1. Remove the side cover of the system unit.
2. By selecting free space on the motherboard, remove the plug on the back of the unit.
3. Install the NIC, secure with the mounting screw.
4. Connect the cable to the LAN adapter socket.
5. Turn on your computer. Light diodes will flash, indicating the exchange of information with the network.
6. Set up the connection: install the driver for the network card, register the server DNS (dns).

Price

The adapter will cost up to $5. The set of functions can be selected as desired (adapter with higher data transfer speed, 2 SFP ports). You can order a set of adapters through the catalog in specialized stores computer equipment or buy in the online store (from 299 rubles). In the table below you will find the price of a network card in Moscow.

Hello dear visitors.

Today we’ll talk about another piece of hardware, and more specifically about what a network card is. You work at a company where you have installed corporate communications between computers? Then you should learn more about the network adapter, since this is what serves link between office computers.

Let's get to know each other better

Not with me, but with the network card, of course.

On English it is called “network interface controller/card” (NIC), that is, “controller or card network interface" Also, according to the technology that is used in the operation of the device, it has another name - Ethernet adapter.

So that you understand its essence, I will decipher the first word: “ether” is translated as “ether”, and network is “network, circuit”. The concept itself means a family of technologies for packet transmission of information among networks of computers.

The network card is designed to create local networks between computers and/or connect them to the Internet. IN lately this is organized using special cable- an eight-core twisted pair cable equipped with an “8P8C” connector, that is, it has 8 conductors in the same number of places for them.

Connect this pair to modern network and a new model card, and you will get speeds from 100 Mbit/s to 1 Gbit (Gigabit).

This technology is called Gigabit Ethernet, which is now relatively popular. Among its main competitors: optical fiber, Docsis (connection of computers using TV cable) And DSL technology(use telephone cable).

The connection can also be made using the transceiver’s 15-pin AUI connector for a thick coaxial cable or a BNC connector for the same cable, only thin.

Types of network cards

The main criterion by which Ethernet adapters are distinguished is their method of connection to the computer:

Basic parameters

Are you thinking about buying a network card? When choosing, consider not only the cable types and interface, but also the following characteristics:

• Bit capacity ( throughput tires). It comes in 8, 16, 32 and 64 bits. IN regular computers As a rule, the device is installed at 32 bits, and in server rooms - the maximum volume. You have absolutely old computer and operating system? Then it might be worth looking at 16 or even 8-bit boards.
• Controller microcircuit (chip). The most reliable are third-generation adapters based on integrated circuits (ASIC). High-quality chipsets are now produced by brands such as Rialtek, Intel, Broadcom, etc.
• Data transfer rate. It starts from 10 Mbit/s and can reach 100 Gbit. But don't chase the highest score. It may be that your hardware is not capable of handling such speed.

What card is on your computer?

Can't answer this question? Then we'll find out now. We go along the path Start - Control Panel - Device Manager (if you have Wimdows). You can find it in the System and Security menu - System. Find the one you need among the devices available on your computer.

In principle, I think I wrote everything in detail.

You now have basic knowledge of network cards. Come back to me for more information.

See you soon, and don't forget to subscribe to blog updates.

Description of network cards for computers and laptops.

Navigation

A network card is a device that allows users to access the Internet, as well as a local network from a computer or laptop. As a rule, modern network adapters have an Ethernet connector to which an Internet cable is connected. It could be fiber optic cable, coming from Wi-Fi devices or the corresponding modem.

In addition, there are also wireless network adapters if the user does not have the ability or desire to run cables across the entire apartment.

In today's review we will discuss in more detail what network cards are, what they are needed for and how they work.

Network cards

As already noted, network cards are essential integral part computer or laptop that allows us to work on the Internet. Network cards may differ from each other in bandwidth, type and other parameters.

What types of network cards are there?

Here we list the main types of network cards:

• Wireless cards are cards that provide an Internet connection when Wi-Fi assistance or Bluetooth devices.
• External - usually used for external connection to laptops via USB port
• Integrated - the most common cards that are built into computers and laptops by default.
• Internal are network cards that can be additionally connected to computers in the corresponding slots on the motherboard.

How do network cards work?

We will not delve too deeply into the operating principle of network cards, since this information will be more understandable only to specialists. Let's explain it more simply. Let's say if you installed fiber optics at home and paid for the Internet, then your provider gives you access to the World Wide Web.

Transmitted via fiber optic cable digital information, which is then processed by the network card. There is nothing complicated about it. When you buy a computer or laptop, as a rule, these devices should already have a built-in network card on the motherboard. The driver for it comes along with the drivers for the motherboard. You only need to install the drivers from the disk, which must be given to you by the seller of your computer/laptop.

All this is so simple that most users simply do not realize that there is a network card on their computer. They connect the cable to network block PC or laptop, pay for the services of their provider and freely use the Internet.

As you might already guess, the computer’s network card is located in its system unit. You just need to open its side cover and pay attention to the lower left corner. You can see this in the screenshot:

How to find a network card on a computer?

If you want to buy a separate internal network card, then you can build it into the corresponding slot in the lower left area of ​​the system unit.

The network card looks like this:

How to find a network card on a computer?

To find out what card you have, you don’t have to go into system unit. Relevant information can be found in a systematic way. To do this, it is not necessary to install third party programs, it is enough to use the means " Windows».

• Go to " Control Panel» via menu « Start»

How can I find out which network card is installed on my computer?

• Next, go to “ System»

How can I find out which network card is installed on my computer?

• Then go to " device Manager»

How can I find out which network card is installed on my computer?

• In the new window, find the item “ Network adapters" and click on it

How can I find out which network card is installed on my computer?

How much does a network card cost?

It's hard to say how much a network card will cost tomorrow, since prices digital devices can constantly change. Different network cards have different prices, let's present some list for today:

How much does a network card cost?

How to choose the right network cards for laptops and computers?

When purchasing a card, of course, you should pay attention to parameters such as media type, bandwidth, and type of network card. It is important to know the classification. But, if you are not an expert, this information You can find out from the seller (buy digital equipment only in well-known official stores). The most important thing is to know in advance which network card from which company you should look for.

Let's list what you need to know when choosing a network card:

• The most famous top manufacturers of network cards: “ D-Link», « Tp-link», « Gembird», « Acorp».
• The network card must have connectors or a connector to be able to connect to a local network (be sure to ask the seller about this).
• To connect to computers, the network card must have a connector " PCI"(especially if you have old computer), and for computers – the “ PCMCIA».
• It is also important to consider what maximum speed Your network card will be able to provide Internet access. Standard cards support speeds up to 100 Mb per second.

Video: How to change the network card?

So what is a network card? The network card is part of the computer's hardware configuration. This device allows us to connect a computer to a network and provides interaction with it. Network cards are often called network interface cards, network adapters or LAN adapters.

Network cards were originally additional component, which could be purchased and installed on a computer not immediately, but after some time. However, today it has become obvious that network cards are a standard computer component that is installed in most laptops and computers sold.

Often, they are integrated into motherboards or other devices during the manufacturing process. If the card is installed in computer system, then it detects itself when connected to the network by small flickering LEDs, which are located at the network connector.

Network Card Identification

Any network card must be unique, so they are equipped with an address, which is abbreviated as MAC. Using it, you can identify any computer transmitting data over the network.

What is a wireless network card

Nowadays, with the help of network cards, you can connect computers using a cable (physical) connection, or you can do without it altogether, using the so-called wireless interface. When using a cable connection, you usually choose a standard network port, which has an RJ-45 format connector. For wireless connection The network does not require the use of different physical ports and interfaces.

Operating principle wireless card pretty simple. Responsible for receiving and transmitting data from the Internet wireless modem. Data from your ISP will be sent to the external port (cable input) wireless router, after which they will be converted into a radio signal, which will be transmitted over the air via an antenna. If wireless network cards are within range of the router's transmitter, they will receive the signal and then convert it into an electronic one, computer understandable signal.

In any case, besides the fact that the wireless network card does not require physical contact with it, its configuration is no different from the usual one. Both wireless and wired cards currently allow almost the same data transfer speed.