Internet via adsl telephone line. aDSL Technology Basics

The acronym ADSL stands for Asymmetric Digital Subscriber Line. ADSL is translated as “Asymmetric Digital Subscriber Line”. This is one of the high-speed data transmission technologies related to DSL (Digital Subscriber Line) technology, also referred to as xDSL.

The group of DSL technologies also includes:

• High speed digital subscriber line. HDSL – High data rate Digital Subscriber Line;
• Ultra-high-speed digital subscriber line. VDSL – Very high data rate Digital Subscriber Line;
• ETTH("Ethernet...");
• GPON;
• FTTH.

What is ADSL technology?

As you already understand, ADSL technology is a technology for connecting to the Internet via wired networks, in particular telephone wires such as twisted pair. The essence of the technology is the ability to carry out high-speed data transmission over twisted pair telephone wires.

To implement this technology, an ADSL line is created that connects two ADSL modems. A twisted pair telephone cable is used to connect ADSL line modems. Each modem is connected to a telephone cable via an RJ-11 connector.

The technology creates 3 channels of information transmission:

• Downdraft;
• Updraft;
• POTS telephone channel.

In this case, the telephone channel is allocated by filters and does not depend on the ADSL connection.

Features of ADSL technology

Firstly, ADSL technology is asymmetrical. This means that the speed of data transfer towards the end user is higher than the speed of data transfer from the user to the network. That is, the speed of the downward flow is higher than the speed of the upward flow.

Secondly. Information transmitted over telephone wires using ADSL technology is compressed. For compression, digital signal processing is used using specially created algorithms, advanced analog filters and analog-to-digital converters.

Third. ADSL technology uses a method of dividing the bandwidth of a copper telephone cable into several carrier frequency bands. This separation allows several signals to be transmitted simultaneously over one line.

In this case, different carrier bands simultaneously transmit different parts of the transmitted data. This process is called Frequency Division Multiplexing (FDM), which means frequency division multiplexing of the communication line.

FDM allows you to allocate one band for the upstream data stream, and a second band for the downstream stream. In this case, the downstream range is divided into high-speed channels and low-speed data channels. The upstream is also divided into low-speed data links.

It is possible to overlap the upstream and downstream ranges with Echo Cancellation technology.

Fourthly. ADSL technology allows you to reserve a narrow band of bandwidth for the transmission of regular telephone service (POTS) signals. POTS is Plain Old Telephone Service. When using ADSL, telephone communication will not be disrupted, even during a power outage.

ADSL Advantage

Despite all the shortcomings, ADSL technology allows you to use already laid telephone wires to connect to the Internet. This globally expands Internet connectivity. This does not require expensive upgrading of switching equipment, as for ISDN technology.

Flaws

The main disadvantage of ADSL is the weakening of the signal on long-distance telephone lines. For example, at a standard speed of 1 MHz, signal loss can be up to 90 dB.

ADSL speed

The first letter in the name ADSL means asymmetric. That is, the transfer of data from the network to the computer (downstream) and the transfer of data from the computer to the network (upstream) will occur at different speeds.

The transmission speed depends on the condition of the line, cable cross-section, and the presence of taps. In fact, the limit for an ADSL subscriber line is a length of 3500 - 5500 meters with a cable cross-section of 0.5 mm 2.

In practice, ADSL will provide speeds to the computer of 1.5 - 8 Mbit/s, and speeds from the computer from 640 to 1.5 Mbit/s.

ADSL and Internet

If you want to connect to the Internet via ADSL, you need to understand that you do not need to dial telephone numbers to communicate. ADSL technology immediately creates a broadband channel for data transmission over an existing telephone line.

Immediately after installing the ADSL modem, you will receive a constant high-speed Internet connection. At the same time, only 1% of the bandwidth is left for telephone communications (low frequency up to 4 kHz). 99% goes to ensuring high-speed data transfer. In this case, different frequency bands are used for different functions.

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Connecting an ADSL modem and setting up an ADSL connection

To establish a connection to the Internet using ADSL technology, you must perform the following steps:

• • Connect the ADSL modem to the telephone line;

  Set up your computer.

Connecting ADSL equipment

Equipment required to connect to the Internet using ADSL technology:

computer;
ADSL modem (hereinafter simply “modem”);
splitter (microfilter);
a set of cables for connecting a computer to a modem and a modem to a telephone network.

Depending on the design of the modem (USB or Ethernet), before connecting, the network adapter (network card) or the driver for the USB modem (USB port) must be installed and working on the computer.

Equipment connection procedure
Connect the splitter to the telephone socket through the LINE connector using the telephone cable supplied with the modem;
Connect your telephone to the splitter via the PHONE connector;
Connect a modem to the splitter by connecting the MODEM connector on the splitter with the DSL connector on the modem using a telephone cable, using the telephone cable included in the delivery kit;
Connect your computer to the modem. The connection is made either by connecting the modem connector (ETH or LAN) and the Ethernet interface of the computer (computer network card), or by connecting the modem to the USB port of the computer using the USB cable included in the delivery kit;
If necessary, connect additional telephone sets in parallel through microfilters that protect phones from high-frequency modem signals.

Connecting an ADSL modem to a telephone line

A typical ADSL modem connection diagram is shown in the figure:

The ADSL splitter separates the frequencies of the voice signal (0.3 - 3.4 KHz) from the frequencies used by the ADSL modem (26 KHz - 1.4 MHz). Thus, the mutual influence of the modem and the telephone is eliminated.
Externally, the ADSL splitter is a small box with 3 RJ-11 type connectors (telephone “Euro sockets”), which are designated “Line”, “Phone” and “Modem”. The telephone line from the city PBX is connected to the “Line” connector of the splitter. The telephone device is connected to the “Phone” connector of the splitter. And finally, the “ADSL” connector of the ADSL modem is connected to the “Modem” connector of the splitter.

Note: Depending on the modem model, the “ADSL” connector may be designated differently, for example “DSL” or “xDSL”. Next, you need to connect the ADSL modem to the computer with an Ethernet cable. To do this, an Ethernet cable is connected at one end to the “Ethernet” connector of the ADSL modem, and at the other end to the computer’s network card.

Connection diagram when using more than one telephone set

Those. The first device connected to the telephone line from the PBX should be an ADSL splitter, to which all other devices are connected. Otherwise, each telephone must be connected through a separate microsplitter:

Connecting a computer to a modem

If your modem allows connections via both Ethernet and USB interfaces, connect the corresponding ports on the computer and modem with the required cable.

If you have a modem with only a USB port, then connect the USB port on your computer with a USB cable to the USB port on the modem.

After

After successfully connecting the modem to the computer and turning on the power, a DSL connection is established between your modem and the Provider’s equipment. In this case, the DSL indicator on the modem should light up and stay lit.

Setting up your computer settings

To configure a PPPoE client in Windows XP, follow these steps:

For Windows

Click Start → Settings → Control Panel → Network Connections →<Мастер новых подключений>(Make new connection) → the Wizard will start, then follow the Wizard menu, click Next (Next) → Connect to Internet → Set up my connection manually → Through a high-speed connection requesting username and password (Connect using a broadband connection that requires a user name and password) → In line<Имя поставщика услуг>(ISP Name) write PeterStar → In the field<Имя пользователя>(Login) write your login in the field<Пароль>(Password) write the password from the sheet<Параметры для пользования Услугой>(received by you at the stage of paying for service connection) → Finish → Connect.

Installing and configuring PPPoE varies somewhat for different operating systems of the Windows family.

Internet connection

To access the Internet, click on the icon.

After entering your login and password, press the OK (Call) button.

If authentication is successful, a connection is established.

Next, launch your Internet browser and type the address www.ya.ru, you are taken to the guest area of ​​the site " www.ya.ru", where (using the login and password from the sheet<Параметры подключения>received at the stage of payment for service connection) you get access to the management page personal account.

On the personal account management page, following the activation instructions attached to the Multicards, activate the Multicards received at the stage of payment for connecting to the Service, and thereby replenish your personal account with the required amount of funds.

After replenishing your personal account, you must<разорвать>and establish a network connection again, to do this, right-click on the icon<сеть>(image of two screens) in the far right bottom corner of the Windows desktop and select<прервать>. After this, run the remote connection program again with your username and password and get full access to the Internet.

Requirements for the Subscriber's computer
CPU 200 MHz and higher
64MB random access memory
network card with Ethernet 10Base-T interface (when connected via an Ethernet cable) or USB (when connected via a USB cable)
operating system Windows 95/98/2000/XP/NT 4.0 and higher. Note: under the Windows NT 4.0 operating system, only ADSL equipment with an Ethernet 10Base-T interface is used

Configuring the TCP/IP protocol parameters of the Ethernet network card to which the ADSL modem is connected. Setting features depend on the specific operating system (OS) installed on the computer and access technology.

Setting up Windows 95, Windows 98, Windows Millenium

First you need to open the network properties window:

Select the “Configuration” tab;
Select the “TCP/IP” element from the list (by clicking the left mouse button);

Finally, you need to enter the TCP/IP protocol parameters:
Select the “IP address” tab;
Select the “Gateway” tab;
If the “Installed gateways” window is not empty, then you need to delete all elements in this window by clicking the “Delete” button;
Select the “DNS Configuration” tab;
Set the “Enable DNS” switch (by left-clicking on this switch);
Enter the network name of the computer you saved earlier in the “Computer name” input field;
If the window located under the “Viewing order” input field DNS servers”, is not empty, then you need to delete all elements in this window by clicking the “Delete” button;
Enter the IP address “195.5.61.70” into the “Order for viewing DNS servers” input field (no need to enter separating dots);
Click on the “Add” button;
Click on the “OK” button;
Click on the “OK” button;
Reboot your computer.

Setting up Windows 2000, WindowsXP

First you need to open the TCP/IP protocol properties window:
Right-click on the “Network Neighborhood” icon on your desktop;
Select the “Properties” menu item;
In the window that appears, right-click on the network connection icon (if there are several network connections, then you need to click on the icon that corresponds to the network card connected to the ADSL modem);
Select the “Properties” menu item;
In the window that appears, select the item “Internet Protocol (TCP/IP)” from the list (by clicking the left mouse button);
Click on the “Properties” button.

Then you need to enter the TCP/IP protocol parameters:
Set the “Obtain an IP address automatically” switch (by left-clicking on this switch);
Set the switch “Use the following DNS server addresses:” (by left-clicking on this switch);
Enter the IP address “195.5.61.70” in the “Preferred DNS server” input field (no need to enter separating dots);
If necessary, clear the “Alternate DNS server” input field;
Click on the “OK” button;
Click on the “OK” button.

Modem settings

To configure the modem, simply specify the following parameters in menu 4 -Internet Acceess Setup:

ISP's Name= killer
Encapsulation= RFC 1483
Multiplexing= LLC-based
VPI #= 0
VCI #= 33

VPI #= 1
VCI #= 32

Operating procedure and troubleshooting.

1.Turn on the power of the ADSL modem

After turning on the power, you need to wait for the modem to boot, which takes about 30 seconds.

2. Make sure that the “Link ADSL” LED of the ADSL modem is lit continuously.

This LED is an indicator of a successful connection to the modem on the station side. While attempting to establish a connection, this LED flashes. The connection is established in approximately 20-30 seconds. Once the connection is established, this LED lights up continuously.

If the LinkADSL LED is off or blinking, then the ADSL modem was unable to communicate with the modem on the station side. This may happen for the following reasons:
The presence of interference in the line or its break;
Splitter malfunction;
Modem freezes;
Poor contact in the telephone wire connectors connected to the splitter and ADSL modem.

Pick up the handset of the seal telephone connected in parallel with the ADSL modem. A telephone buzzer (continuous tone) should be heard in the handset. If there is no buzzer, then connect the telephone directly to the line, bypassing the splitter. If the buzzer appears, then the splitter is faulty, otherwise there is a line break. If the buzzer is heard against a background of strong interference (noise, crackling), then in this case there is interference in the line.

If the line is broken or there is interference in the line, you must contact technical support.

If the buzzer is normal, then try connecting the ADSL modem directly to the line, bypassing the splitter. If after this the connection is established (the “ADSLLink” LED is continuously lit), then the splitter is faulty.

If the connection still does not appear, try the following:
Reboot the modem by cutting the power supply;
Check the integrity of the telephone wires connecting the splitter and the ADSL modem;
Press the plugs of the telephone wires connected to the splitter and ADSL modem into the connectors (it is possible that the plug is not fully inserted into the connector);

If specified measures did not help, then you need to contact technical support.

3. Make sure that the “Link LAN” LED of the ADSL modem is on.

If this LED is not lit, then there is no connection between the ADSL modem and the computer via the Ethernet network. Try the following:
Check the integrity of the Ethernet cable connecting the computer and the ADSL modem;
Press the plug of the Ethernet cable connecting the computer and the ADSL modem into the connectors (it is possible that the plug is not fully inserted into the connector).

If Windows 2000 or Windows XP is installed on your computer, then for some reason the network interface may be disabled by software. In this case it is necessary:
Right-click on the “Network Neighborhood” icon on your desktop;
Select the “Properties” menu item;
Make sure that the network interface to which the ADSL modem is connected is turned on (below the name of the network connection there should be a line “Enabled”).

If the network interface is disabled (there is a line “Disabled”), then you must:
Right-click on the network connection;
Select the “Enable” menu item.

If none of the above measures help, then you need to contact technical support.

4. Go online.

If one or another HTML page cannot be opened, this does not mean there is a malfunction. It is possible that the server on which the requested page is located is turned off or unavailable. Try opening pages located on other servers. If this fails, then try opening the page at www.ya.ru. If this page does not open, then you need to contact technical support.

In recent years, the development of the telecommunications services market has led to a shortage of capacity for access channels to existing provider networks. If at the corporate level this problem is solved by providing high-speed data transmission channels for rent, then what alternative can be offered to subscribers on existing lines, instead of a dial-up connection, in the residential and small business sectors?

Today, the main way end users interact with private and public networks is access using a telephone line and modems, devices that provide the transmission of digital information over subscriber analog telephone lines - the so-called Dialup connection. The speed of such communication is low, the maximum speed can reach 56 Kbps. This is still enough for Internet access, but the pages are saturated with graphics and video, large volumes Email and documents, the ability for users to exchange multimedia information, posed the task of increasing the throughput of the existing subscriber line. By decision this issue, was the development of ADSL technology.

ADSL technology (Asymmetric Digital Subscriber Line - asymmetric digital subscriber line) is the most promising at present, at this stage of development of subscriber lines. It is part of a general group of high-speed data transmission technologies, united by the general term DSL (Digital Subscriber Line).

The main advantage of this technology is that there is no need to lay a cable to the subscriber. Already laid telephone cables are used, on which splitters are installed to separate the signal into “telephone” and “modem”. Different channels are used to receive and transmit data: the receiving channel has significantly greater throughput.

The general name for DSL technologies arose in 1989, when the idea of ​​using analog-to-digital conversion at the subscriber end of the line first appeared, which would improve the technology of data transmission over twisted pair copper telephone wires. ADSL technology was developed to provide high-speed (one might even say megabit) access to interactive video services (video on demand, video games, etc.) and equally fast data transfer (Internet access, remote access to LANs and other networks). Today DSL technologies are presented:

• ADSL (Asymmetric Digital Subscriber Line - asymmetric digital subscriber line)

This technology is asymmetric, that is, the data transfer rate from the network to the user is much higher than the data transfer rate from the user to the network. This asymmetry, combined with the state of a “permanently established connection” (which eliminates the need to dial each time phone number and wait for the connection to be established), makes ADSL technology ideal for organizing access to the Internet, access to local area networks (LAN), etc. When organizing such connections, users usually receive much more information than they transmit. ADSL technology provides downstream data rates ranging from 1.5 Mbit/s to 8 Mbit/s and upstream data rates from 640 Kbit/s to 1.5 Mbit/s. ADSL allows you to transmit data at a speed of 1.54 Mbit/s over a distance of up to 5.5 km over one twisted pair of wires. Transfer speeds of the order of 6-8 Mbit/s can be achieved when transmitting data over a distance of no more than 3.5 km via wires with a diameter of 0.5 mm.

• R-ADSL (Rate-Adaptive Digital Subscriber Line)

R-ADSL technology provides the same data transfer speed as ADSL technology, but at the same time allows you to adapt the transfer speed to the length and condition of the twisted pair wires used. When using R-ADSL technology, the connection on different telephone lines will have different data transfer rates. The data rate can be selected by line synchronization, during connection or by signal coming from the station

• G. Lite (ADSL.Lite)

It is a cheaper and easier to install version of ADSL technology, providing downstream data speeds of up to 1.5 Mbit/s and upstream data speeds of up to 512 Kbit/s or 256 Kbit/s in both directions.

• HDSL (High Bit-Rate Digital Subscriber Line)

HDSL technology provides for the organization of a symmetrical data transmission line, that is, the data transmission speeds from the user to the network and from the network to the user are equal. With transmission speeds of 1.544 Mbps over two pairs of wires and 2.048 Mbps over three pairs of wires, telecommunications companies are using HDSL technology as an alternative to T1/E1 lines. (T1 lines are used in North America and provide a data transfer rate of 1.544 Mbit/s, and E1 lines are used in Europe and provide a data transfer rate of 2.048 Mbit/s.) Although the distance over which the HDSL system transmits data (which is about 3.5-4.5 km) is less than with ADSL technology, telephone companies can install special repeaters to inexpensively but effectively extend the length of an HDSL line. The use of two or three twisted pairs of telephone wires to organize an HDSL line makes this system an ideal solution for connecting remote PBX nodes, Internet servers, local networks, etc.

• SDSL (Single Line Digital Subscriber Line)

Just like HDSL technology, SDSL technology provides symmetrical data transmission at speeds corresponding to the speeds of the T1/E1 line, but SDSL technology has two important differences. Firstly, only one twisted pair of wires is used, and secondly, the maximum transmission distance is limited to 3km. Within this distance, SDSL technology provides, for example, the operation of a video conferencing system when it is necessary to maintain the same data transfer flows in both directions.

• SHDSL (Symmetric High Speed ​​Digital Subscriber Line - symmetrical high-speed digital subscriber line

The most modern type of DSL technology is aimed primarily at ensuring guaranteed quality of service, that is, at a given speed and data transmission range, ensuring an error level of no worse than 10 -7 even in the most unfavorable noise conditions.

This standard is a development of HDSL, since it allows the transmission of a digital stream over a single pair. SHDSL technology has several important advantages over HDSL. First of all, these are better characteristics (in terms of maximum line length and noise margin) due to the use of more efficient code, a pre-coding mechanism, more advanced correction methods and improved interface parameters. This technology is also spectrally compatible with other DSL technologies. Because the new system uses a more efficient linear code compared to HDSL, then at any speed the SHDSL signal occupies a narrower frequency band than the HDSL signal corresponding to the same speed. Therefore, the interference generated by the SHDSL system to other DSL systems is less powerful than the interference from HDSL. The spectral density of the SHDSL signal is shaped in such a way that it is spectrally compatible with ADSL signals. As a result, compared to the single-pair version of HDSL, SHDSL allows you to increase the transmission speed by 35-45% at the same range or increase the range by 15-20% at the same speed.

• IDSL (ISDN Digital Subscriber Line - IDSN digital subscriber line)

IDSL technology provides full duplex data transmission at speeds up to 144 Kbps. Unlike ADSL, IDSL's capabilities are limited to data transmission only. Despite the fact that IDSL, like ISDN, uses 2B1Q modulation, there are a number of differences between them. Unlike ISDN, the IDSL line is a non-switched line that does not increase the load on the provider's switching equipment. Also, an IDSL line is "always on" (like any line organized using DSL technology), while ISDN requires a connection to be established.

• VDSL (Very High Bit-Rate Digital Subscriber Line - ultra-high-speed digital subscriber line)

VDSL technology is the "fastest" xDSL technology. It provides downstream data transfer rates ranging from 13 to 52 Mbit/s, and upstream data transfer rates ranging from 1.5 to 2.3 Mbit/s, over one twisted pair of telephone wires. In symmetric mode, speeds up to 26Mbps are supported. VDSL technology can be seen as a cost-effective alternative to laying fiber optic cable to the end user. However, the maximum data transmission distance for this technology is from 300 meters to 1300 meters. That is, either the length of the subscriber line should not exceed this value, or the fiber-optic cable should be brought closer to the user (for example, brought into a building in which there are many potential users). VDSL technology can be used for the same purposes as ADSL; In addition, it can be used to transmit high-definition television (HDTV), video on demand, etc. signals. The technology is not standardized; different equipment manufacturers have different speed values.

So what is ADSL? First of all, ADSL is a technology that allows you to turn twisted pair telephone wires into a high-speed data transmission path. The ADSL line connects the provider's DSLAM (DSL Access Multiplexor) access equipment and the customer's modem, which are connected to each end of the twisted pair telephone cable (see Figure 1). In this case, three information channels are organized - the "downstream" data transmission stream, the "upstream" data transmission stream and the regular telephone service (POTS) channel (see Figure 2). The telephone communication channel is allocated using a frequency splitter filter, and directs it to the usual telephone device. This scheme allows you to talk on the phone simultaneously with the transfer of information and use telephone communication in the event of a malfunction of the ADSL equipment. Structurally, the telephone separator is a frequency filter, which can be either integrated into the ADSL modem or be a separate device.

Rice. 1


Rice. 2

ADSL is an asymmetric technology - the speed of the “downstream” data flow (that is, the data that is transmitted towards the end user) is higher than the speed of the “upstream” data flow (in turn, transmitted from the user to the network). It should be said right away that there is no cause for concern here. The data transfer rate from the user (the "slower" direction of data transfer) is still significantly higher than using an analog modem. This asymmetry is introduced artificially; the modern range of network services requires a very low transmission speed from the subscriber. For example, to receive videos in MPEG-1 format, a bandwidth of 1.5 Mbit/s is required. For service information transmitted from the subscriber (command exchange, service traffic), 64-128 Kbit/s is quite sufficient. According to statistics, incoming traffic is several times, and sometimes an order of magnitude, higher than outgoing traffic. This speed ratio ensures optimal performance.

To compress large amounts of information transmitted over twisted pair telephone wires, ADSL technology uses digital signal processing and specially created algorithms, advanced analog filters and analog-to-digital converters. Long distance telephone lines can attenuate the transmitted high frequency signal (eg at 1MHz, which is the typical transmission rate for ADSL) by up to 90dB. This forces analog ADSL modem systems to operate under a fairly heavy load to allow for high dynamic range and low noise levels. At first glance, the ADSL system is quite simple - high-speed data transmission channels are created over a regular telephone cable. But, if you understand in detail how ADSL works, you can understand that this system belongs to the achievements of modern technology.

ADSL technology uses a method of dividing the bandwidth of a copper telephone line into several frequency bands (also called carriers). This allows multiple signals to be transmitted simultaneously on one line. Exactly the same principle underlies cable television, when each user has a special converter that decodes the signal and allows them to see a football match or an exciting film on the TV screen. When using ADSL, different carriers simultaneously carry different parts of the transmitted data. This process is known as Frequency Division Multiplexing (FDM) (see Figure 3).

Rice. 3

In FDM, one band is allocated for the upstream data stream and another band for the downstream data stream. The downstream information stream is divided into several information channels - DMT (Discrete Multi-Tone), each of which is transmitted on its own carrier frequency using QAM. QAM is a modulation method - Quadrature Amplitude Modulation, called quadrature amplitude modulation (QAM). It is used to transmit digital signals and provides for discrete changes in the state of a carrier segment simultaneously in phase and amplitude. Typically, DMT splits the 4 kHz to 1.1 MHz band into 256 channels, each 4 kHz wide. This method, by definition, solves the problem of dividing the bandwidth between voice and data (it simply does not use the voice part), but is more complex to implement than CAP (Carrierless Amplitude and Phase Modulation) - amplitude-phase modulation without carrier transmission. DMT is approved in the ANSI T1.413 standard and is also recommended as the basis of the Universal ADSL specification. In addition, echo cancellation technology can be used, in which the upstream and downstream ranges overlap (see Figure 3) and are separated by local echo cancellation.

This is how ADSL can provide, for example, simultaneous high-speed data transmission, video transmission and fax transmission. And all this without interrupting regular telephone communication, for which the same telephone line is used. The technology involves reserving a certain frequency band for regular telephone communications (or POTS - Plain Old Telephone Service). It's amazing how quickly telephone communication turned not only into "simple" (Plain), but also into "old" (Old); it turned out something like “good old telephone communication”. However, we should pay tribute to the developers of new technologies, who still left telephone subscribers a narrow band of frequencies for live communication. In this case, a telephone conversation can be carried out simultaneously with high-speed data transfer, rather than choosing one of the two. Moreover, even if your electricity is cut off, the usual “good old” telephone connection will still work and you will not have any problems calling an electrician. Providing this capability was part of the original ADSL development plan.

One of the main advantages of ADSL over other high-speed data transmission technologies is the use of ordinary twisted pair copper telephone cables. It is quite obvious that there are much more such pairs of wires (and this is an understatement) than, for example, cables laid specifically for cable modems. ADSL forms, so to speak, an "overlay network".

ADSL is a high-speed data technology, but how high-speed? Considering that the letter “A” in the name ADSL stands for “asymmetric”, we can conclude that data transfer in one direction is faster than in the other. Therefore, there are two data transfer rates to consider: "downstream" (transferring data from the network to your computer) and "upstream" (transferring data from your computer to the network).

Maximum speed reception - DS (down stream) and transmission - US (up stream), depends on many factors, the dependence on which we will try to consider later. IN classic version, ideally, the reception and transmission speed depends on and is determined by DMT (Discrete Multi-Tone) dividing the bandwidth from 4 kHz to 1.1 MHz into 256 channels, each 4 kHz wide. These channels in turn represent 8 digital streams T1, E1. For down stream transmission, 4 T1,E1 streams are used, the total maximum throughput of which is 6.144 Mbit/s - in the case of T1 or 8.192 Mbit/s in the case of E1. For up stream transmission, one T1 stream is 1.536 Mbit/s. Maximum speed limits are indicated without taking into account overhead costs, in the case of classic ADSL. Each stream is provided with an error correction code (ECC) by introducing an additional bit.

Now let's look at how real data transfer occurs using the following example. IP information packets generated as in local networks clients and personal computers directly connected to the Internet will be sent to the input of an ADSL modem framed by the Ethernet 802.3 standard. The subscriber modem splits and “packs” the contents of Ethernet 802.3 frames into ATM cells, supplies the latter with a destination address and transmits them to the output of the ADSL modem. In accordance with the T1.413 standard, it “encapsulates” ATM cells into the digital stream E1, T1, and then the traffic over the telephone line arrives at the DSLAM. The DSL multiplexor station concentrator - DSLAM, carries out the procedure of “restoring” ATM cells from the T1.413 packet format and sends them via the ATM Forum PVC (Permanent Virtual Circuit) protocol to the backbone access subsystem (ATM network), which delivers the ATM cells at the address indicated in them, i.e. to one of the service delivery centers. When implementing Internet access services, cells arrive at the Internet provider's router, which performs the function of a terminal device in a permanent virtual channel (PVC) between the subscriber terminal and the Internet provider's node. The router performs the opposite (in relation to the subscriber terminal) transformation: it collects incoming ATM cells and restores the original frame of Ethernet 802.3 format. When transmitting traffic from the service delivery center to the subscriber, completely similar transformations are carried out, only in the reverse order. In other words, a “transparent” local network of the Ethernet 802.3 protocol is created between the Ethernet port of the subscriber terminal and the virtual port of the router, and all computers connected to the subscriber terminal perceive the Internet provider’s router as one of the local network devices.

The common denominator in the provision of Internet access services is the IP network layer protocol. Therefore, the chain of protocol transformations carried out in a broadband access network can be represented as follows: client application - IP packet - Ethernet frame (IEEE 802.3) - ATM cells (RFC 1483) - modulated ADSL signal (T1.413) - ATM cells (RFC 1483 ) - Ethernet frame (IEEE 802.3) - IP packet - application on a resource on the Internet.

As mentioned above, the stated speeds are only possible ideally and without taking into account overhead costs. So in the E1 stream, when transmitting data, one channel (depending on the protocol used) is used to synchronize the stream. And as a result, the maximum speed, taking into account overhead costs, will be Down stream - 7936 Kbps. There are other factors that have a significant impact on the speed and stability of the connection. These factors include: line length (the throughput of a DSL line is inversely proportional to the length of the subscriber line) and wire cross-section. The characteristics of the line deteriorate as its length increases and the wire cross-section decreases. The data transfer speed is also affected by the general condition of the subscriber line, the presence of twists, and cable outlets. The most “harmful” factors that directly affect the ability to establish an ADSL connection are the presence of Pupinov coils on the subscriber line, as well as a large number of taps. None of the DSL technologies can be used on lines with Pupin coils. When checking a line, it is ideal not only to determine the presence of Pupin coils, but also to find the exact location of their installation (you will still have to look for the coils and remove them from the line). The Pupin coil used in analog telephone systems is a 66 or 88 mH inductor. Historically, Pupin coils were used as a structural element of a long (more than 5.5 km) subscriber line, which made it possible to improve the quality of transmitted audio signals. A cable outlet is usually understood as a section of cable that is connected to the subscriber line, but is not included in the direct connection of the subscriber to the telephone exchange. The cable outlet is usually connected to the main cable and forms a "Y" shaped branch. It often happens that the cable outlet goes to the subscriber, and the main cable goes further (in this case, this pair of cables must be open at the end). However, the suitability of a particular subscriber line for using DSL technology is influenced not so much by the fact of the connection itself, but by the length of the cable outlet itself. Up to a certain length (about 400 meters), cable outlets do not have a significant impact on xDSL. Additionally, cable outlets affect different xDSL technologies differently. For example, HDSL technology allows for a cable outlet of up to 1800 meters. As for ADSL, cable outlets do not interfere with the very fact of organizing high-speed data transmission over a copper subscriber line, but they can narrow the line bandwidth and, accordingly, reduce the transmission speed.

The advantages of a high-frequency signal, which makes it possible to digitally transmit data, are its disadvantages, namely susceptibility to external factors (various interference from third-party electromagnetic devices), as well as physical phenomena that arise in the line during transmission. An increase in the capacitive characteristics of the channel, the occurrence of standing waves and reflections, and the insulation characteristics of the line. All these factors lead to the appearance of extraneous noise on the line, and faster attenuation of the signal and, as a consequence, to a decrease in the data transmission speed and a decrease in the length of the line suitable for data transmission. The ADSL modem itself can provide some values ​​of the characteristics of the ADSL line, by which one can directly judge the quality of the telephone line. Almost all models of modern ADSL modems contain information about the quality of the connection. Most often, the Status->Modem Status tab. Approximate contents (may vary depending on the model and manufacturer of the modem) are as follows:

Modem Status

Connection Status Connected
Us Rate (Kbps) 511
Ds Rate (Kbps) 2042
US Margin 26
DS Margin 31
Trained Modulation ADSL_2plus
LOS Errors 0
DS Line Attenuation 30
US Line Attenuation 19
Peak Cell Rate 1205 cells per sec
CRC Rx Fast 0
CRC Tx Fast 0
CRC Rx Interleaved 0
CRC Tx Interleaved 0
Path Mode Interleaved
DSL Statistics

Near End F4 Loop Back Count 0
Near End F5 Loop Back Count 0

Let's explain some of them:

Connection Status Connected - connection status
Us Rate (Kbps) 511 - Up Stream speed
Ds Rate (Kbps) 2042 - Down Stream speed
US Margin 26 - Outgoing connection noise level in db
DS Margin 31 - Downlink noise level in db
LOS Errors 0 -
DS Line Attenuation 30 - Downlink signal attenuation in db
US Line Attenuation 19 - Signal attenuation in the outgoing connection in db
CRC Rx Fast 0 - number of uncorrected errors. There are also FEC (corrected) and HEC errors
CRC Tx Fast 0 - number of uncorrected errors. There are also FEC (corrected) and HEC errors
CRC Rx Interleaved 0 - number of uncorrected errors. There are also FEC (corrected) and HEC errors
CRC Tx Interleaved 0 - number of uncorrected errors. There are also FEC (corrected) and HEC errors
Path Mode Interleaved - Error correction mode is enabled (Path mode Fast - disabled)

Based on these values, you can judge, and also control yourself, the state of the line. Values:

Margin - SN Margin (Signal to Noise Margin or Signal to Noise Ratio). The noise level of interference depends on many different factors - getting wet, the number and length of branches, line synchronicity, cable “breakage”, the presence of twists, the quality of physical connections. In this case, the signal of the outgoing ADSL stream (Upstream) decreases until it is completely absent and, as a consequence, the ADSL modem loses synchronization

Line Attenuation - the attenuation value (the greater the distance from DSLAMa, the greater the attenuation value. The higher the signal frequency, and therefore the connection speed, the greater the attenuation value).

Testing Methodology for ADSL

The testing methodology is intended to evaluate and visually display test results when problems arise when working on the Internet.
You can read how to take a “screenshot” .

We draw your attention to some features of working on the Internet:
1) When the Subscriber connects to its Data Network, the Provider is not responsible for the quality of communication outside the subscriber's terminal device (if any) connected to the Provider's equipment.
The provider guarantees Internet access speed only under the condition of a direct connection, i.e. The Provider's cable connects directly to a laptop or personal computer. You can read more about the Procedure for the provision of services.
2) You can familiarize yourself with the division of areas of responsibility between the Provider and the Subscriber.
3) When using ADSL technology, the data transfer speed is always less than the connection speed by at least 13-15%. This is a technological limitation, which we will discuss in more detail later. It does not depend on the provider or the modem used.
Under ideal conditions, with a connection speed of 12 Mbit/s, you can count on maximum real speed~ 10 Mbit/s.
Note! You can find out more about the factors affecting the data transfer speed when using ADSL technology.

Attention! If you use Wi-Fi wireless networks to surf the Internet, it will be useful for you to read the information below.
1. Sources of interference affecting the operation of wireless Wi-Fi networks may be the following:
- material of walls and partitions in your apartment or office;
- location of your neighbors' Wi-Fi points. For example, if your neighbor’s point is located near the wall adjacent to your apartment, and your point, in turn, is located near this wall, then the signals from both points will interrupt each other;
- Wi-Fi module in your PC or other mobile device. A mobile device may not have the most modern module installed, which has a maximum speed limit;
- simultaneous downloading from different devices, both inside your apartment and at neighboring points outside your apartment;
- Bluetooth devices operating within the coverage area of ​​your Wi-Fi device;
- various household appliances that use the 2.4 GHz frequency range when operating within the coverage area of ​​your Wi-Fi device.
You can find out more about possible sources of interference affecting the operation of wireless Wi-Fi networks.

2. To speed up your work on the Internet and make it more stable, you need to:
- configure the router to work with mobile devices. How to do this on a TP-Link router, see;
- choose a freer channel;
- select the optimal location of the Wi-Fi point;
- purchase an external Wi-Fi adapter;
- use a two-antenna wireless access point operating in the 2.4 GHz band;
- use a wireless access point operating in the 5 GHz band;
- work via Ethernet cable.

You can learn more about ways to increase your Wi-Fi connection speed and bandwidth.

Testing methodology

Attention! If you are connected through additional equipment or use wireless Wi-Fi networks, you must first connect the Internet cable directly to your laptop or personal computer without additional devices, and then perform the speed testing procedure.

To obtain adequate results during each of the test points, NO work on the Internet should be carried out!

For Windows OS
Download the archive. Unpack it to any folder on your computer. The file should appear in the same folder TEST.bat. We launch it and wait from 10 to 20 minutes (depending on the quality of the DSL connection).
Attention! For Windows 7 and Windows 8, you must run the file as an administrator (right-click on TEST.bat and select “Run as Administrator”). When the BAT file has completed all the actions, you will see the following window.

Press any key on the keyboard and the window will close. After that we go to Drive C and find text files there PING.txt, PATHPING.txt And CONFIG.txt . We attach these files to the results.

For Mac OS X
Download the archive. Unpack it to any folder on your computer. After unpacking, a file should appear in the same folder Test.app. We launch it and wait from 10 to 20 minutes. After completing the test, press any key on the keyboard - the window will close.
Once testing is complete, three text files will appear on your desktop - CONFIG, PING, TRACEROUTE. We attach these files to the results.

• We measure Internet speed.
  A) Let's go by link and press the button "Begin Test". We are waiting for the test to complete.

  When the test is completed, you will be presented with a window similar to this. Let's make it " screenshot” and attach it to the results.

  b) Download the file (size about 75 MB) from here: http://www.apple.com/itunes/download/
  We start downloading by clicking on the button "Download Now".
  During the download process we do "screenshot"
  Attention! To display the download speed in the browser, you need to go to the Downloads section by pressing the key combination Ctrl+J.

  With) Upload the file big size(about 2.3 GB) from here:
  ftp://ftp.freebsd.org/pub/FreeBSD. During the download process we do "screenshot" Your download manager or browser and attach it to the testing results.
  Attention! There is no need to download the entire file! It’s enough to wait a minute or two until a stable speed is established, then do 2-3 “ screenshot"with an interval of 20-30 seconds and stop the download.

  d) Download the file using a torrent client. For correct speed testing, it is necessary to exclude local retrackers. You can see how to do this.
  Attention! It is necessary to test the connection speed when downloading 3-4 files at the same time, for which the number of uploaders is more than 100. During the download process, do “ screenshot» Your torrent client and attach it to the test results.

• We measure speed from internal resources. For this Minsk subscribers come in next link .

  On the website click on "Change Server".

  In the search bar we write "Atlant Telecom" and select it as a server.

  Then press the button "GO".
  We are waiting for testing to be completed.

  As a result, a window with the results should appear.

  We take a screenshot and attach it to the overall results.

  Regional subscribers go to the following links and download the file:
  - link for Brest;
  - link for Vitebsk;
  - link for Grodno;
  - link for Gomel;
  - link for Mogilev.
  During the download process, we take a “screenshot” of your download manager or browser (except Internet Explorer) and attach it to the testing results.

• Download the program and install it (for D-link brand modems - program).

  Zyxmon- free Windows program for managing and monitoring the status of Zyxel routers.

  Unpack the zip folder using some archiver. For example, WinRAR or WinZIP. Run the executable file " ZyxMon" A program window will open. Click on the button " Settings"(circled in red).

  

  The following window will appear. Filling out the fields Router IP And Router password. Click " OK».

• After pressing " OK"we will return to the Main window of the program. We activate the connection with the modem. To do this, press the button " Telnet Router Connections" (circled in pink), while the indicators " Telnet connection status" And " PPPoE session status"will have to change color from red to green.

  Description of bookmarks:
  Telnet: Modem connection status and PPPoE status.
  Log: Modem text log;
  SyslogD: Messages received from the Syslg Daemon modem;
  SNMP: RealTime channel filling statistics;
  DynDNS: Dynamic DNS status (not used);
  Line: Data required for testing the line: noise margin , attenuation . To receive data you need to press the “ Get ”.

  Let's do " screenshot” of the obtained result and attach it to the test results.

We check at what speed the modem receives/sends data.

a) telnet.
Let's go to command line: Start -> Run -> cmd -> Ok . In the window that appears, write the command telnet (for example, telnet 192.168.1.1) and press the key "Enter". In the next step you will be prompted for a password. "Password" , enter the password (by default - 1234 ) and press the key "Enter".
From the main menu of the modem, go to the menu 24.1 - System Maintenance - Status . To do this, press on the keyboard 24 - “Enter”, 1- “Enter”. Let's take screenshots of this window:




Explanations for the fields of interest to us in this menu:
Tx B/s - transfer speed in Bytes per second;
Rx B/s [Reception speed, Bytes/s] - reception speed in Bytes in seconds;
Up Time [Connection time] - duration of connection between the modem and the provider;
My WAN IP (from ISP) [my IP address on the global network (from the provider)] - the IP address received by the modem from the provider;
Line Status [Line status] - current xDSL line status: Up - up, Down - not up;
Upstream Speed [Outgoing speed] - transmission speed of outgoing traffic in Kbps;
Downstream Speed [Incoming speed] - transmission speed of incoming traffic in Kbit/s;
CPU Load [CPU load] - percentage of modem CPU load.

b) For modems ZyXel 660R, ZyXel 660R-T1, ZyXel 660RU-T1, ZyXel 660HT1, ZyXel 660HW-T1 via WEB interface.

192.168.1.1 and press the key "Enter". 1234 and press the button "Login". "Ignore"
In the main menu of the modem, select "System Status". In the window that opens, find the button "Show Statistics" and press it. Let's do " screenshots» last window:
- first: during downloading from the Internet;
- second: during downloading from internal resources.
We name the files accordingly and attach them to the results.

c) For modems ZyXel 660R-T2, ZyXel 660RU-T2, ZyXel 660HT-2, ZyXel 660HW-T2.

Type in the address bar of your Internet browser (Chrome, Mozilla Firefox, etc.) the address 192.168.1.1 and press the key "Enter". Next, a window will appear asking for a password. We register 1234 and press the button "Login". A window will appear in which you are advised to change the password for logging into the modem. Press the button "Ignore"
In the main menu of the modem, click "Status", and in the window that opens, click the link "Packet Statistics".
As a result, a statistics window will open, do it “ screenshot»:
- first: during downloading from the Internet;
- second: during downloading from internal resources.
We name the files accordingly and attach them to the results.

d) For D-Link 2500/2540/2600/2640U v.2 modems

Type 192.168.1.1 in the address bar of your Internet browser (Chrome, Mozilla Firefox, etc.) and press the " Enter " Next, a window will appear asking for a user and password. We register the user - admin and password - admin , press the button " Ok ».
Next we go to the menu Device Info -> Statistics -> WAN
As a result, a window will open, do it “ screenshot»:
- first: during downloading from the Internet;
- second: during downloading from internal resources.

We diagnose the DSL channel connection.
To do this we go: Start -> Run -> cmd -> Ok.
In the window that appears, write the commands one by one (after each press the key "Enter" ):
netsh("Enter")
ras("Enter")
set tracing ppp enable("Enter")
exit("Enter")
Next, go to the Windows folder (usually c: Windows) and create a folder there tracing . If it writes to you that such a folder already exists, do not be alarmed. We go into it (example path: c:Windowstracing) and copy the ppp.txt file from there with the results of the commands we entered earlier. We attach this file to the results of the method.

Analyzing the DSL channel on the modem.

a) For modems ZyXel 660R, ZyXel 660RT1, ZyXel 660RU1, ZyXel 660HT1, ZyXel 660HW-T1
We go to the modem configurator, as shown in step 6-a, go to the menu - modem command line. We write the commands one by one (after each press the key "Enter" ):
wan adsl chandata ("Enter")
wan adsl opmode (“Enter”)
wan adsl linedata far (“Enter”)
wan adsl linedata near (“Enter”)
wan adsl perf (“Enter”)
wan hwsar disp (“Enter”)
Let's do " screenshots» the results obtained. First of all, the state of the 1st (physical) level is analyzed. This information is retrieved using the commands “xdsl state”, “wan adsl linedata far”, “wan adsl linedata near”. Link for information: http://zyxel.ru/kb/1543.
The main parameters for monitoring are “SNR margin value”, “Loop attenuation” for 782 and 791, and “noise margin downstream”, “attenuation downstream” - for 642, 650, 650, 660. Both values ​​are measured on the receiving channel of the transceiver. The first universally characterizes the noise immunity margin of the line. A level of 6 db roughly corresponds to an error rate of 10E-6 and is the threshold for reliable communication. This parameter clearly depends on the speed, i.e. the higher the speed, the smaller the margin. It is also worth noting that the measured values ​​at each of the line terminals may differ. This indicates that the source of interference is located closer to one end of the line.
Attenuation downstream is the attenuation of the signal in the line and clearly depends on the active resistance of the wire. The effect of noise on communication quality and maximum speed is higher than that of attenuation. You need to do this several times a day different time days. The results should be attached to the results of the method.

b) For modems ZyXel 660RT2, ZyXel 660RU2, ZyXel 660HT2, ZyXel 660HW-T2, ZyXel 660RT3, ZyXel 660RU3, ZyXel 660HT3
When entering the modem settings via telnet (as shown in point 6-a), you will immediately be taken to the modem command line, where you need to enter the commands indicated above.

c) For ZyXel 700 series modems (782 and 791)
In a similar way, go to the modem configurator (see point 6-a) and go to the menu 24.8 - Command Interpreter Mode.
We write the commands one by one (after each press the key "Enter" ):
xdsl cnt disp ("Enter")
wan hwsar disp (“Enter”)
xdsl state ("Enter")
Let's do " screenshots» obtained results and attach them to the test results.

d) For D-Link 2500/2540/2600/2640U v.2 modems
We go to the modem configurator, as shown in point 6-d, go to the menu Device Info -> Statistics -> ADSL .
Take a screenshot and attach it to the results.


We save all the results of the testing methodology in one archive and send them to the technical support email address [email protected] indicating client data (personal account number/organization name, contact phone number/email address) for feedback.

Rostelecom is one of the largest providers in Russia, providing a variety of services: Internet, interactive television, telephone communications and others.

Most devices on the market can work on its network. Some of them are offered by the company to subscribers upon connection.

One of them is D-Link DSL-2640U. Let's look at what kind of device this is and how to configure it for the correct operation of all services.

Short description

The DSL-2640U router manufactured by D-link is a universal device for accessing the Internet using ADSL technology, that is, through a telephone line. Additionally, the device is equipped with 4 ports for connecting computers, set-top boxes or other equipment and a built-in Wi-Fi interface for wireless Internet access.

Firmware versions

Users may encounter two types of interface of the DSL-2640U router from Rostelecom, slightly different from each other. They depend on the firmware version. It is very easy to distinguish between old and new firmware:

• Old software version. The interface is designed in white and blue.
• New firmware version. Interface colors: dark gray and black.

Login to the router settings management interface

Before you start setting up the DSL-2640U router from Rostelecom, you need to take it out of the box, connect it to the telephone line, computer and outlet.

Once the physical installation is complete, you can begin configuring the device. All configurations are performed through the router management web interface. To access the settings, you must perform the following steps in sequence:

1. Launch any browser (Google Chrom, Opera, IE, etc.).
2. Type 192.168.1.1 in the address bar.
3. Press Enter.
4. When prompted to enter your username and password, enter “admin” without quotes in both fields. This is the data that is used for authorization.

Internet setup

Rostelecom uses PPPoE in most places to connect to the Internet, so we will consider configuration based on it. In the old and new versions Firmware settings items are located slightly differently, so we will provide a description for each option separately.

Old firmware

In the main menu, sequentially select the items “Network”, “Connections” and click on the add button. On the screen that appears, set the following parameters:

• "Connection type". Here you need to select the PPPoE mode. This will allow the D-link DSL-2640U to operate in router mode.
• VPI and VCI. These options vary in each region. You can clarify them in technical support using a toll-free number or by finding the corresponding table on the Internet.
• We enter a username and password for access. You can find out this data from the documents that were received upon connection. Important! The password must be confirmed in the next field.
• Service name. At this point, enter a name for the connection that will allow you to identify it, for example, “Internet”.
• Extra options. For normal operation, you must enable the checkboxes next to the “Keep Alive” and “IGMP” items.

If the line leaves much to be desired and frequent connection breaks are possible, then it is better to indicate the actions to take if an authorization attempt is unsuccessful. In the “LCP failures” field we indicate the value 2, and in the “LCP interval” - 15. This will allow the device to first try to establish a connection twice, and then pause for 15 seconds.

New firmware

The sequence of actions in the new firmware is somewhat different. After logging into the management interface, the user sees several buttons and information about the device and ADSL operation status on the main page.

The first thing you need to do to set up the Internet is to switch to advanced management mode. The button for this is located at the very bottom of the screen.

In the “Network” section, select “WAN”. A window with available connections will open. If it is not empty, then before setting it up you need to delete all connections; to do this, click on them successively with the mouse and select “Delete” in the lower right corner of the screen.

Click the “Create” button in the WAN interfaces and begin configuration.

In the window that appears, you must specify standard parameters, namely:

1. Connection type - PPPoE. This is what Rostelecom uses for all subscribers connected via ADSL technology.
2. “Interface” - DSL (new). Otherwise, it will not be possible to specify the VPI and VCI settings.
3. VPI and VCI. These two parameters can be found in technical support.

At this point, the Internet settings are completed and if you do not need to connect a set-top box for IP TV, you can save the settings and reboot the DSL-2640U. To do this, at the top right of the D-link logo, find the “System” menu and select the desired action.

Setting up a router to connect an IPTV set-top box

IPTV is actively promoted by Rostelecom under the name “Interactive Television”. Often subscribers can use this service for several months as a gift when connecting to the Internet. To configure the service on the DSL-2640U router from D-link, you will need to complete two steps:

1. Creating connections. There may be one or two of them for IPTV operation, depending on the region.
2. Grouping of ports.

Old firmware

Again in the main menu, select the “Connections” sub-item in the “Network” section. Set the “Connection type” switch to the Bridge position and set the VPI/VCI pair. If two sets of parameters are possible, then repeat the procedure again.

After creating a connection, you need to perform port grouping. To do this, go to the “Advanced” section of the main menu and select the “Interface Grouping” item. On the page that appears, select the appropriate button at the very bottom to add a group. Fill in the “Name” field with any name, for example “TV”.

And we move from the left column to the right two bridge connections and ports for the set-top box (usually one, for example, LAN2).

New firmware

The actions that owners of the D-link DSL-2640U router with the new firmware need to perform are similar, but the menu is slightly different, so here is their order:

• Go to “Advanced Settings” and go to the “WAN” item in the “Network” section.

• Click “Add”.
• Set the “Connection type” switch to the “Bridge” position, and in the “Interface” drop-down menu select the “DSL (new)” value.
• Specify VPI and VCI, and then save the connection
• If necessary, create a second connection of the “Bridge” type for the second VPI/VCI pair.
• On the “Advanced Settings” page, in the “Advanced” section, click on the “Interface Grouping” item.
• Click the “Add group” button.

• Specify any name for new group and check the required ports, for example, LAN 4 and one or two Bridge connections.
• Click the “Apply” button.

Setting up wireless Internet access

Devices that access the Internet via Wi-Fi can be found in every home today. To provide them with wireless access to the network via D-link DSL-2640U, you need to make some settings.

Old firmware

First you need to set the name of the network. This is done on a special page, which can be accessed by sequentially selecting the “Wi-Fi” and “Basic settings” items in the main menu. The only thing that needs to be specified on this page is the name of the network. You need to enter it in the appropriate field, which is called “SSID”. After entering the data, you should save using the special button below.

It is important not only to create a Wi-Fi network, but also to make it secure enough so that personal data is not at risk. This can be done by setting a key or password for it.

This operation is performed on a special “Security Settings” page, which can be accessed through the “Wi-Fi” section in the main menu.

Rostelecom can rightfully be considered one of the largest providers in Russia. This provider provides its subscribers with a variety of services, such as Internet, telephone, and others. Most devices on the market are suitable for connecting to the Rostelecom network. The company offers some devices to its subscribers when connecting to services. One such device is the D-Link DSL-2640U. In this article, we suggest that you familiarize yourself with this router and its settings.

Brief characteristics of the router

The DSL-2640U router from D-link is designed to connect to the Internet using ADSL technology, that is, through a thin telephone cable. In addition, this device has built-in Wi-Fi for wireless Internet and 4 ports for connecting computers, TV set-top boxes or other equipment.

Firmware versions

The DSL-2640U router can be found with two types of interface, which depend on different firmware versions. You can distinguish old and new firmware by color. The interface of the old firmware version is made in white and blue, and in dark gray and black.

Login to the router admin panel

To set up the router, first of all you need to connect it to your computer, telephone cable and outlet. Once the connection is complete, you can begin setting up device configurations. All settings are made using the router web management interface. To log into the management system of the DSL-2640U router, follow the instructions:

• Open an internet browser on your computer.
• In the address bar, write the device address – 192.168.1.1.
• Press Enter.
• Next, you need to log in to the system. To do this, enter the value admin in both username and password fields.

Setting up an Internet connection

Most often, Rostelecom provides the Internet to its subscribers via a PPPoE connection, so this article describes the setup based on it. The settings items in different firmware versions are also located differently, so we will describe the settings process for each option separately.

Old firmware version

In the main menu of the interface, select “Network”, then “Connections” and click “Add”. In the window that opens, set the following parameters:

• In the “Connection type” item, select PPPoE.
• Enter the values ​​for the “VPI” and “VCI” parameters. You can find them out at Rostelecom technical support, since this data is individual for each region of the country.
• Enter your username and password to access the Internet. This information is usually provided by the provider when concluding a contract for the provision of services. The password must be entered in the next field to confirm it.
• IN next point come up with and write a name for your connection.
• In the additional parameters, you must check the “Keep Alive” and “IGMP” items.
• In the “LCP failures” field, enter the value 2, and in the “LCP interval” field - 15. Thanks to these settings, if the connection is lost, the device will try to connect to the network 2 times, and if the attempts are unsuccessful, it will pause for 15 seconds.

New firmware version

After successful authorization, the main interface page will open on your screen, which contains information about the router and several buttons. To further configure the device, you need to switch to the advanced control mode using the corresponding button at the bottom of the screen.

• Next, select “WAN” in the “Network” section. In the window that opens, delete all existing connections; to do this, select them and click “Delete”.
• In the “WAN” item, click the “Create” button.

A window will open on the screen in which specify the following parameters:

• Connection type - PPPoE.
• “Interface” - DSL (new).
• The values ​​of the VPI and VCI parameters for your region, which can be found in Rostelecom technical support or searched on the Internet.

After completing the steps, setting up the Internet can be considered complete. If you do not plan to connect an IPTV set-top box, you can reboot the device and use the Internet. To reboot, use the corresponding button in the “System” menu at the top right of the D-link logo.

Setting up IPTV television

Rostelecom is actively offering subscribers an IPTV service called “Interactive Television”. To configure IPTV on the DSL-2640U router, you must do the following:

In old firmware

• In the main menu, in the “Network” section, select “Connections”.
• In the “Connection type” column, set the value to “Bridge” and enter the VPI/VCI values ​​(these values ​​will differ from those you entered for the Internet connection). Depending on the region, IPTV may require one or two connections to operate. If two sets of parameters are needed, then repeat the procedure again.
• Now that the connection has been created, we need to group the ports. To do this, go to the “Advanced” section and select “Interface Grouping”.
• Add a group using the appropriate button at the bottom of the page.
• Come up with and enter a name for the group in the “Name” field.
• Move two bridge connections and ports for the set-top box from the left column to the right (usually one, for example, LAN2).

In the new firmware

• Open "Advanced Settings", then in the "Network" section, go to "WAN".

• Click Add.
• In the “Connection Type” item, select “Bridge”, and in the “Interface” drop-down menu, set the value to “DSL (new)”.
• Specify VPI and VCI (these values ​​will be different from those you entered for the Internet connection) and save the created connection. Depending on the region, IPTV may require one or two connections to operate. If necessary, create a second similar connection for another VPI/VCI pair.
• In the "Advanced" section on the "Advanced Settings" page, click "Interface Grouping".
• Click the “Add Group” button.

• Specify any name for the group to be created and check the boxes for the required ports and bridge connections.
• Click Apply.

Setting up a Wi-Fi network

To use wireless Internet via Wi-Fi, you must complete the following router settings:

For old firmware

• In the main menu, go to the “Wi-Fi” section, then select “Basic settings”.
• On the page that opens, you must enter the name of your network in the “SSID” field and click the “Save” button.

Everyone has long known that a Wi-Fi connection should be as secure as possible so that personal data is not at risk and so that other users cannot use your Internet. Therefore, it is recommended to set a password for your Wi-Fi network.

• Through the “Wi-Fi” section in the main menu, enter the “Security Settings” item.
• Select the authentication type “WPA2-PSK”, then enter the password in the appropriate field (do not forget to write down the password, since without it you will not be able to connect to the created Wi-Fi network). After that, click the “Change” button.

For new firmware

• In the "Advanced Settings" section, set the Wi-Fi switch to the "On" position.

• In the Wi-Fi section, select “Basic settings”.
• Enter the name of the network to be created in the “SSID” field and click “Apply”.

Let us remind you that the Wi-Fi connection must be protected from unauthorized users. Therefore, you need to return to the “Advanced Settings” section and enter the “Security Settings” item. Select “WPA2-PSK” as the authentication type and enter the network access password in the appropriate field.

Once the setup is complete, all that remains is to save all the settings and restart the device. As a rule, setting up routers does not cause any difficulties for users. However, if you are unable to connect and configure your router, please contact .

XDSL technology from Rostelecom and a number of other providers has long replaced analog modems, whose maximum speed was limited to 56K. The ability to transmit data over the same lines as the telephone not only saved operators on laying new wires, but also provided good quality Internet communications for users.

XDSL from Rostelecom: what is it?

Interested in the question of what XDSL is and how to connect the Internet from Rostelecom using this technology? The abbreviation XDSL stands for Digital Subscriber Line or, translated into Russian, Digital Subscriber Line. The maximum speed of incoming traffic using this technology can reach 8 Mbit/s. The main role in the development of DSL was played by the low price of equipment, as well as the absence of the need to lay additional communication lines.

Analog modems, which also operated via a telephone cord, have long been a thing of the past for two reasons:

• low communication speed;
• inability to use the Internet simultaneously with the phone.

This option was especially inconvenient at a time when the communication line was divided into two apartments. Thus, if one of the subscribers was talking on the phone or using the Internet, the other did not have any access to telecommunications services.

XDSL technology has completely solved this problem. Thanks to it, the signal no longer needed to be converted from analog to digital on a computer, but was transmitted directly. In addition, the problem with simultaneous use of the Internet and telephone was also taken into account. Now the user could enjoy two services at the same time.

Of course, when talking about XDSL technology, one cannot fail to mention that there are many branches of its development: ADSL, IDSL, HDSL, SDSL, VDSL.

ADSL technology, which has earned the maximum number among all types of XDSL connections from Rostelecom and other providers positive feedback both among experts and among users, it has gained the greatest popularity. This is easily justified by its speed characteristics. The data transfer technology in this case is asynchronous. In practice this means that the incoming and outgoing speeds are different meanings. The maximum throughput “to the user” is limited to 8 Mbit/s. The outgoing connection speed does not exceed 768Kbps. Nevertheless, for use as a home or work network, such characteristics are quite sufficient. An ADSL connection can provide a comfortable experience not only when surfing the Internet, but also when playing high-definition online content and participating in multiplayer games.

One of interesting technologies Internet connection is VDSL. This is the fastest way to transfer data over a telephone line. But due to the fact that this technology is also asymmetric, the data reception speed had to be sacrificed, which is no more than 2.3 Mbit/s. But the outgoing throughput here has grown to a huge value for DSL communication of 52 Mbit/s.

The remaining technologies did not gain much popularity, since they could not boast of their speed characteristics.

Pros and cons of XDSL connection

Despite the fact that there are faster methods of accessing the Internet on the telecommunications services market, the number of Rostelecom clients using XDSL communication lines represents a fairly large audience. This is easily explained by the main advantage of the technology – cost minimization. Unlike a fiber optic connection, which requires additional cabling, XDSL operates over the telephone line found in almost every home.

However, such a connection may not always work correctly. For example, if the provider's substation is located remotely, the Internet speed will drop noticeably. Weather conditions, which directly affect the telephone line, can also lead to a deterioration in the quality of communication.

Compared to a fiber optic connection, a telephone line is not capable of providing stable speeds of up to 100 Mb/s.

For Rostelecom users who want to activate the promotional package of “Non Stop” services, it is worth noting that the declared speed of 50 Mbit/s cannot be achieved when using XDSL equipment.

Attention: If you are already using a tariff with a speed of 8 Mbit/s, you will not be able to increase the line capacity to a higher value. Nevertheless, the tariffs for XDSL services from Rostelecom themselves are less expensive.

The XDSL connection from Rostelecom, which made a breakthrough in data transfer speed in the past, still represents a good option for accessing the Internet. Download speeds of up to 8 Mbit/s and low connection costs without the need for additional cables become decisive factors when choosing a telecommunications service.

The technology of broadband high-speed access through telephone lines - ADSL was initially considered transitional from the ancient Dial-Up to the more or less modern FTTB ETTH technology, and no one thought that it would live so long. Nevertheless, ADSL lives and is not going to rest in God yet. With its help, the private sector is connected to the outskirts of megacities. And in smaller towns and in rural areas This may actually be the only high-speed technology. And even despite this, the quality of services provided through the existing telephone lines is falling every year, less and less money is allocated for servicing LKS, to the point that even line crews sometimes do not receive a field worker for repairs for a month or more. With cable damage, the situation is sometimes even worse. Providers try to squeeze out maximum profits at minimal costs and at the same time “put a good face on a bad game”: short deadlines for eliminating damage are set, installers are chased from corner to corner, and more noise-resistant profiles are set on station equipment.
Subscribers want to keep up with the times and demand the highest possible data transfer speed. Is it possible to somehow influence it and how to get the most out of your line, we’ll talk today.

The maximum download speed via ADSL, according to specifications, is 24 megabits per second. Is it really achievable? Yes, it can be achieved, but only on short lines of very good quality. But is it worth bothering with this? The fact is that telecom operators are not fools either, and tariff plans are made that can be supported by a regular telephone line - often up to a maximum of 8 or even 6 Mb/s.

Accordingly, even if there are 20-21 Megabits per second on the line, you still won’t be able to accelerate beyond the tariff. But if the operator has its own file-sharing network, or has some interesting internal resources such as game servers and torrent portals, then it makes sense.

ADSL technology has 2 main factors on which speed depends:
- Setting up access equipment
- Communication line quality
They are closely interconnected with each other. On an ideal line, reduce the speed to a minimum on one side and no matter how optimally the equipment is configured, the “bottleneck” will be a barely alive line. Therefore, the approach must be comprehensive.

Configuring ADSL equipment for maximum performance:

What is an ADSL line? These are two modems connected to each other by a telephone line. One is on the subscriber's side, the other is on the provider's side. When you turn on the modem at home, it coordinates the signal parameters and speed with its fellow station. This procedure is called HandShake. After which the link rises to the best values ​​obtained.

You can view the current ADSL connection speed in the web interface of your modem on the status page. For example, this is how it looks on the D-Link DSL-2640U:

On some modem models it is possible to view more extensive information:

Here the configuration of the device at both ends of the line plays a significant role. Pay attention to the “Calculated speed” parameter; it is significantly higher than the connection speed. This means that the line still has a certain resource that can be used. Of course, it is not a fact that you will be able to achieve the values ​​​​that the modem calculated, but it is quite possible to squeeze out half of this difference.

This can only be done if the equipment is correctly configured. On the subscriber device side, there are very few available settings:

In fact, you can only change the modulation used - for example, leave only ADSL 2+. If you need a higher upload speed, also check the box AnnexM. But again, these modulations must be enabled on the station modem, otherwise the coordination will not take place, the link will not go up, and therefore there will be no sense in these actions. Therefore, you need to call the technical support of your telecom operator and chat with them. Moreover, first you will have to go through the “filter” of the first line and, by any means, contact the engineers who are directly involved in the station equipment and set speed profiles at the ports.

Here it is worth saying a separate word about the relationship with the provider’s technical support. Firstly, people work there and where one person can easily help, another can simply refuse and that’s it. Secondly, there are certain regulations that employees must comply with. And no matter how you ask, you won’t get more than you can.

If you can find mutual language with a specialist, he can choose the optimal profile for you, or the maximum one. This is what it looks like on the station DSLAM:

Although I would not recommend pushing the maximum - you will lose in noise immunity and if interference occurs on the line, you will lose the link. It’s better if the connection is a little slower, but more stable.

Another trick is to ask the support staff to enable Fast Mode on your port. In simple words- this is a profile on DSLAM with error correction disabled. Due to this, the ping on the last mile becomes a little less and the response speed increases accordingly.

Checking and repairing telephone (dedicated) line

First of all, remember - Everything that goes to the house (apartment) is the responsibility of the provider. But now the wiring around the house or apartment - you are already responsible for this. Here, of course, there are also some nuances. For example, if the main cable is old, then there is practically no chance of replacing it. In my memory, the cases of cable replacement can be counted on one hand. Basically, only repairs, replacement of cable joints, etc. are done.

The situation is not easy in the last section from the distribution box to you.
If you live in a private house with an overhead cable input, then, as I said above, sometimes getting the installer to replace the field switch can be very difficult. And the field worker itself (cable P-274, P-274M and P-279) has not been of good quality lately. Therefore, by all means, try to replace it with a new cable - TCPPt, also sometimes called “digital”:

With its help, we were once able to connect a subscriber at a distance of 5 kilometers from the station and at the same time provide him with a speed of about 6 Mb/sec. For such a length, this is simply an ideal speed.

In a multi-storey building, from the KRT box to the outlet in the apartment, the so-called “Noodles” are usually thrown - TRP cable, TRV cable, etc. I don’t like it at all - a bad, unreliable and brittle cable. It’s better to buy a two-pair twisted pair UTP-2x2xo.5 yourself. Firstly, this is a more reliable cable. Secondly, it will have a second, backup pair. And thirdly, it can be crimped into an RJ11 telephone connector and plugged into an ADSL splitter. This will eliminate another weak link - the telephone socket.

If the socket is already installed, but of an old type with an adapter for the RJ11 “Euro” connector, it is better to replace it with a new one:

Adapters are usually of very low quality and often fail. And the sockets themselves, after 10-15 years of operation, begin to deteriorate due to dirty and oxidized contacts.

The wiring throughout the apartment must be intact and without twists. The more damage and twisted connections there are, the worse the quality of the line will be and the lower the data transfer speed of the ADSL line. If the wire is old, and even has a couple of twists on it, it is better to replace it with a new one. Twisted pair is also great for this.

As an option, you can use a 2-pair CPSV (I don’t recommend a single-pair one - it’s flimsy in my opinion).

Remember, only a good line with a good, intact cable can provide excellent ADSL Internet speed and best quality high-speed communication channel.