Attention to confidentiality
ADSL Maintenance Manual
Guizhou Telecom Network Operation and Maintenance Department
May 2004
Introduction
In recent years, ADSL technology has been developing rapidly and has shown a good momentum of development, and has become a mainstream broadband access technology. With the rapid development of ADSL service, the maintenance problem of ADSL service has become more and more prominent. In order to enable the staff of all departments to quickly and accurately determine the type of faults in the maintenance work, reduce the time of service interruption, and improve the maintenance level, we have collected and organized some information, and prepared a manual for the reference of the majority of maintenance personnel.
In the process of writing the manual, Guiyang Operation Center and Qiannan Telecom Branch Data Center provided us with a lot of information, and we would like to express our thanks.
Due to the shortage of time and experience, errors and omissions are unavoidable, and we hope that all local networks will reflect their opinions to us in the process of using the manual, so that it can be revised in the future.
Editor
Table of Contents
Chapter 1 Introduction to ADSL Basics... 1
Chapter 2 ADSL Installation... 3
Chapter 3 ADSL Maintenance... 18
Appendix I Handling Simple ADSL Obstacles in EVERYTHING UPTELL Authentication System
Appendix II Analysis of ADSL Disconnection Phenomenon
Chapter I Introduction to ADSL Basics
I. Principle of ADSL
1. Basic Concepts
ADSL (Asymmetric Digital Subscriber Line) is the abbreviation of Asymmetric Digital Line, which is a kind of technology that provides broadband data transmission service for home and office through the existing ordinary telephone line.ADSL is an asymmetric digital signaling, which is able to provide broadband data transmission service in the existing ADSL is an asymmetric digital signal transmission, which can provide high-speed downlink rate of up to 8Mbit/s on existing copper twisted-pair lines, i.e. ordinary telephone lines, while the uplink rate has 2Mbit/s, and the transmission distance is up to 3km----5km. ADSL makes full use of the existing telephone network, and ADSL equipments can be installed at both ends of the line to provide high-bandwidth services for users. ADSL can be stored with ordinary telephones*** on a single telephone line, and in ADSL can be used with ordinary telephone **** in a telephone line, in an ordinary telephone line to receive, dialing the phone at the same time for high-speed digital signal transmission without affecting each other.
2. Working Principle
1) Line Spectrum
ADSL makes full use of the frequency spectrum of the twisted copper wire. The entire spectrum is divided into three parts: (1) the traditional voice service band, about 4kHz bandwidth; (2) ADSL uplink duplex low-speed channel, located in the voice spectrum above; (3) ADSL downlink simplex high-speed channel, located in the high-frequency part.
In the echo-canceling ADSL system, the downlink channel overlaps with the uplink channel (mainly to take advantage of the low-frequency part of the signal attenuation is small). Compared with the frequency division multiplexing technology, echo cancellation technology eliminates the interference (such as near-end crosstalk) due to frequency superposition, and thus can make the ADSL system in the performance index has been greatly improved. However, relatively speaking, echo cancellation technology is more difficult, hardware integration requirements are higher.
2) Line Coding
The main ADSL line transmission technologies are Quadrature Amplitude Modulation (QAM), Carrierless Amplitude Phase Modulation (CAP), and Discrete Multitone (DMT). Compared with QAM and CAP technologies, DMT technology has many advantages, and it is easier to realize transmission rates above 6Mb/s. The ANSIT1.413 standard specifies that DMT technology is the preferred technology.
DMT is a multicarrier modulation technique that divides the entire frequency band into 256 subchannels. A training sequence is sent in advance to measure the characteristics (signal-to-noise ratio) of each sub-channel, and according to the ability of the sub-channel to send data, a 1-11bit signal is allocated to each sub-channel, and the sub-channel that cannot send data is turned off. Good performance can be obtained for those loops subject to crosstalk and RF carrier interference, and the whole system can allocate data adaptively.
The DMT system can be viewed as a set of continuously parallel QAM systems, with each QAM carrier frequency corresponding to a DMT subchannel frequency. Multi-carrier modulation (demodulation) requires orthogonal modulation between the different sub-channels, which is realized by means of the Fast Fourier Transform (FFT). Since the cable characteristics of each sub-channel vary nearly linearly, its impulse noise produces a minimal effect. The energy of the impulse noise affects the received characters, but the FFT spreads it out over many sub-channels within the FFT window, resulting in a low likelihood of generating a false code.
II. Main features and typical applications of ADSL
1. Main technical features of ADSL
ADSL technology adopts an asymmetric transmission structure suitable for subscriber data access services, which can provide subscribers with high-speed transmission channels. ADSL access system adopts advanced line coding and modulation technology, and has a better ability to adapt to the user line. ADSL access systems can support both voice and data services, and separate data and voice traffic in the access segment of the network structure. ADSL access system can make full use of the existing municipal telephone network in a large number of copper cable resources, and can be coordinated with the development of fiber optic access network in the fiber optic cable laying plan, so as to provide users with high-quality data access services.2, ADSL typical applications
Internet high-speed access services A variety of broadband multimedia services, such as video-on-demand VOD, online concert halls, online theaters, online games, Internet TV, etc. ATM or IP-based VPN (virtual private network) services Provide point-to-point remote visual conferencing, telemedicine. Telemedicine, Distance Learning, etc.Chapter 2 ADSL Installation
I. ADSL Installation Process
Business Acceptance - Wiring Ordering - Equipment Room Pre-opening - Outside Line Return Order.
II. ADSL Hardware Installation
1. ADSL Access Model
The access model of ADSL mainly consists of the central switching office module and the remote module. The central switching end module includes the ADSL Modem in the center and the access multiplexing system, and the ADSL Modem in the center is called ATU-C (ADSL Transmission Unit-Central). The ADSL Modem at the center is called ATU-C (ADSL Transmission Unit-Central), and the Access Multiplexing System-Central Modem is usually grouped into a node called Access Node, which is also called "DSLAM" (DSL Access Multiplexer). As shown in the figure below:
2. Basic information of ADSL main components
1) Bearer phone
Each ADSL line must be attached to an ordinary telephone line, which is called a bearer phone
2) NIC
The network interface card is a device that allows computers to be connected to the network and communicate with other computers in the network. devices that enable computers to connect to a network and communicate with other computers in the network.
3) ADSL Modem
A modem, also known as a modem, is a device that converts analog signals to digital signals. The analog signals transmitted over a normal telephone line are analog signals. The Modem converts the analog signals transmitted over the telephone line into digital signals that can be recognized by the computer, and at the same time converts the digital signals from the computer into analog signals that are sent out over the telephone line.
4) Separator
The role of the separator is to separate the high-frequency signals used by ADSL from the low-frequency signals used by ordinary local calls, and users with extensions should make parallel connections after the telephone line has passed through the separator.
5) Cable
Twisted pair: two insulated copper wires are twisted around each other in a certain pattern, which can effectively resist external electromagnetic interference.
Parallel wire: is the relative position of the two wires remain unchanged, anti-interference ability is poor, into the home of the parallel line more than 20 meters of the user, the parallel line to be replaced by a twisted pair of wires first.
Network cable: consists of four pairs of twisted-pair cable and two RJ45 crystal head.
3, the correct connection
Separator can not be connected before the extension, anti-theft devices, etc., if there is an extension, it should be connected after the separator, the figure shows the correct way to connect the MODEM and the separator.
Common problems with the home wire:
A, B wire is not wrapped with insulating tape, resulting in occasional short circuits with the touch of external forces. A, B line in the socket at the moisture and lead to A, B line insulation resistance is too low or A, B line a line touch the ground. The length of the user line reaches more than 2.5km, and the length of the in-home parallel line with iron or aluminum core is more than 20 m. The external line port of the splitter is connected to a telephone extension, fax machine, audio Modem, voice station dialer, IP dialer, etc. The line plug is not connected to the external line port of the splitter. The line plug has poor contact with the socket. An audio Modem, voice station dialer, IP dialer, telephone immobilizer, etc. are connected in series on the external line port of the splitter.4, the correct ADSL telephone sub-installation
1) Simple installation
Splitter
Telephone line
ADSL Modem
Telephone
Advantages: Simple line, the use of the phone and the Internet do not interfere with each other, fewer failures, easy to maintain.
Disadvantages: telephone without a secondary phone is not convenient to use nearby. (Cordless phone can be used)
2) Installation of splitter and telephone sub
Splitter
Telephone line
ADSL Modem
Telephone mainframe
Installation of splitter
Telephone sub
Advantage: You can increase the number of sub according to the needs of the user, and it is convenient to use. Internet access and phone calls do not affect each other.
Disadvantages:
Increased telephone vice line and separator, the line tends to be complex, increasing the potential for failure, not conducive to troubleshooting. Increased equipment costs.Note: When using more than one separator, at most one low-impedance separator can be used, and the rest use high-impedance separator, otherwise it is easy to appear due to the line impedance mismatch of telephone echo.
3) Install a telephone sub after the splitter
Splitter
Telephone line
ADSL Modem
Telephone mainframe
Telephone sub
Advantages:
The telephone circuit and the ADSL circuit are separated in the splitter, which is convenient for use and maintenance. No need to install additional separators, economical. If it is a newly renovated house, you can lay all the lines in a concealed pipe, beautiful, low failure rate, long service life.Drawbacks: If the line is laid, the number of lines, not beautiful.
Three. ADSL software installation
The ADSL access methods currently available are leased line access and virtual dial-up access. Dedicated line into the network way (i.e. static IP method) by the telecommunications company to the user to assign a fixed static IP address, this way of accessing the Internet is relatively simple; virtual dial-up access (i.e. PPPOE dialing) is not dialing a telephone number, the cost of the telephone service has nothing to do with the user to enter the account number, password, through the identity of the user to obtain a dynamic IP address, the user needs to be added to the computer to install the The user needs to install a PPPOE dialing client software in the computer.
The software setup for ADSL Internet access can be divided into the following steps.
1, the installation and setup of the network card
Because the ADSL modem is connected to the computer through the network card, so before installing the ADSL modem, you need to install the network card, which can be a 10M network card, or a 10/100M adaptive network card. The installation steps are as follows (take the installation of 3COM EtherLink III PCMCIA NIC under WIN98 as an example):
1) Reboot the system after inserting the NIC, and WINDOWS will search for the NIC automatically after the boot screen.
2) Select the type of NIC in the device list and insert the driver disk or CD-ROM according to the system prompts.
3) After the installation is complete, the 3COM Etherlink III card will appear in the System Properties section of the Control Panel.
4) Click on Properties and make sure the card is working properly and not conflicting with other hardware in the General tab.
For private line users, set the IP address, subnet mask, gateway, and DNS server address in the TCP/IP properties; for virtual dial-up users, use the default settings.
2. Installation of Virtual Dialing Software
There are many types of PPPoE dialing software, and the following three are common:
Enternet 300 (Enternet100 Enternet500): PPPoE software developed by Efficient Networks Inc. of the U.S.A., which provides the ADSL PPPoE protocol, complete the virtual dial-up Internet work, applicable to win98, win2000, winNT/4.0. WinPoET: PPPoE software developed by the U.S. WindRiver company, providing ADSL PPPoE protocol to complete the work of virtual dial-up Internet work, applicable to winme, win98, win2000. WinPoET: PPPoE software developed by the U.S. WindRiver company, providing ADSL PPPoE protocol to complete the work of virtual dial-up Internet work, applicable to winme, win98, win2000, RasPPPoE: PPPoE software developed by German Netizen, provides PPPoE protocol for ADSL to complete the virtual dial-up Internet work. It is suitable for winme, win98, win2000.The following describes how to install Enternet 300.
1) Installation under WINDOWS95/98/me
(1) Go to the installation software directory and double-click the program file "setup.exe".
(2) The installation program starts.
(3) Select the Quick Install (accept default settings) option, click the Next button and wait for the computer to automatically install the PPPOE software and drivers.
(4) Select Yes (Restart) when the following window appears and click the Finish button.
(5) Follow the prompts to restart the computer and complete the PPPOE software installation.
(6) After the computer restarts, select and double-click the EnterNet 300 icon on the desktop.
(7) In the new window, select the Create New Profile icon and double-click it.
(8) Enter the ADSL dial-up connection name, for example: ADSL, and click the Next button.
(9) In the next window, enter the correct username and password, you need to enter the password twice.
(10) Continue to press the Next button to go to the next window.
(11) Click the Finish button in the Finish Connection window to go to the next window.
(12) A new icon ADSL appears in the Profile - EnterNet 300 window, select and double-click this icon to open the ADSL connection.
(13) Click the Connect button in the Dialing window to establish an ADSL PPPOE call.
(14) "Beginning Negotiation" begins to appear in the "Messages" status bar of the EnterNet 300 window, indicating that an attempt is being made to establish a connection with the server.
(15) Then "Authenticating" is displayed in the Messages status bar, indicating that the server is authenticating.
(16) Then "Receiving Network Parameters" is displayed in the Messages status bar, indicating that the server is obtaining IP and other parameters.
(17) Finally, the entire EnterNet 300 window disappears and the icon of the two computers connected appears in the Windows status bar in the lower right corner of the computer screen, indicating that the connection has been successfully established.
(18) At this point, the user can access the Internet.
(19) When you want to disconnect from the network, you can double-click the icon above, and in the window that appears, click the Disconnect button.
2) Installation in WINDOWS2000
Open Network Neighborhood, select the ADSL device connected to the network card "local connection", right-click into the Properties panel, select "Installation", and then select "Protocol". "Protocol", select from the "disk installation", and then locate the path directory where the PPPOE software is located, and finally determine, the installation process WIN2000 system will be prompted several times "no digital signature! "You don't have to pay attention to it. After the installation is completed and restarted, the installation steps are basically the same as on WIN98, so I won't repeat them here.
3) WINDOWSXP under the installation
Windows XP is the latest Windows operating system launched by Microsoft, Windows XP has integrated the PPPOE protocol, ADSL users do not need to install any other PPPOE dialing software, directly using the Windows XP Connection Wizard to establish their ADSL
(1) After installing the NIC driver, select (Start-> Programs-> Accessories-> Communications-> New Connection Wizard).
(2) The Welcome to the New Connection Wizard screen appears, so click Next.
(3) Then select Connect to the Internet by default and click Next.
(4) Here, select "Manually set up my connection" and click Next again.
(5) Select "Connect with a broadband connection that requires a username and password" and click Next.
(6) prompted to enter the "ISP name", here is just a name of the connection, you can enter, for example: "ADSL", and then click "Next! "
(7)
(7) Here you can choose whether this connection is for any user or just for yourself, just click Next.
(8) Then enter your ADSL account number (i.e. username) and password (be sure to note the format and case of the username and password), and follow the wizard's prompts to set up some other Windows XP security settings for this connection, and then click "Next".
(9) This completes the PPPOE dial-up setup for Windows XP.
(10) After clicking "Finish", you will see a connection icon named "ADSL" on your desktop.
(11) If you confirm that your username and password are correct, click Connect to dial-up.
(12) After successfully connecting, you will see the icon of two computers connected in the lower right corner of the screen.
Four. User-side network debugging
Hardware requirements for the user side:
Computer: INTEL Pentium III and above and the same grade CPU microcomputer ADSL terminal equipment (Modem) a 10m or 10/100m adaptive network card (usb port modem can be exempted) RJ45 cable (usb port modem can be exempted) RJ45 cable (usb port modem can be exempted) modem can be exempted) RJ11 telephone line aThe user side of the software requirements:
Recommended to use WIN98 and above operating system. Browser recommended to use IE4.0 or above, or Netscape4.0 or above.Network debugging for static IP users
The modem uses the manufacturer's default mode. Set IP address, subnet mask, gateway and DNS in Computer Control Panel - > Network - > TCP/IP (Binding NIC) Protocol.Network debugging for PPPOE users
The modem adopts the factory default mode. The user side vpi, vci value should be 0, 35, if the modem default value is not 0, 35 must log in to the modem to modify the method is as follows: 1) the use of ADSL network card in the TCP / IP protocol of the IP address is set to "192.168.1.x" subnet mask is set to "255.255.255.255.255.255.255.255.255.255.255.255.255.255.255.255.255.255.255.255. "255.255.255.0"; 2) in the IE browser address bar, type "Options" and select "Connections" in the "Never make a Dial-up connection" check box. Select "Local Area Settings" here "auto-detect" and "use a proxy server" before the unchecked. Click "OK" and go to "Advanced" and click "Restore Default Settings" and click "OK". Open a web page and try it.Three. ADSL line test program
Since ADSL user access is carried in the city copper twisted-pair cable for high-speed data transmission, each user has a different computer terminal, the user Modem, the city cable, DSLAM data ports and so on, and finally through the transmission link to access the network server. Therefore, when measuring an ADSL line, it will be tested simultaneously according to layered and segmented measurements to evaluate the location of faulty segments and transmission performance.
1) Layered Measurement
Layered measurement is mainly divided into data link layer, protocol layer and physical layer measurement. The data link layer is mainly Modem simulation test, and the DSLAM link with the bureau, to see whether the parameters on the data link layer are normal, whether it is in line with the requirements of ADSL link transmission; the protocol layer is mainly ping test, to verify the validity of the user account password, and at the same time, verify that the data in the server room is correct; the physical layer measurement is the physical line test, the quality of the cable, the physical properties of the test and evaluation. testing and evaluation. In the physical layer test is mainly through the segmentation measurement to locate.
2) Segmentation measurement
Segmentation measurement is mainly used to locate the faulty line, and to find the section or point of occurrence of the problem. In segmentation measurement, the whole link is generally divided into the local section, the subscriber line section and the subscriber section. In the local section there are DSLAM port equipment, data management, switching equipment, access equipment, etc.; the user line section is mainly 112 room wiring, security units, trunk cable, downstairs cable, downstairs cable, user indoor line, separator and user Modem; the user section includes the user's computer and the local area network (LAN).
Because the quality of various cables involved in the subscriber line segment varies greatly, and at the same time, ADSL transmission performance is mainly affected by the length and quality of the cable, therefore, the subscriber line segment problem has become the main problem affecting ADSL transmission performance.
3) ADSL Line Test Parameters and Standards
(1) Indicators and Standards for ATU-R Subscriber MODEM Emulation Test
Link Emulation Test
Name
Target Value
Measured Value
Fast Channel Rate Fast
Uplink (kbps)
User Requested Value
Downstream (kbps)
User Requested Value
Interleaved Channel Rate INTL
Uplink (kbps)
User Requested Value
Downstream (kbps)