Broadband repair manual

Broadband repair manual
Part 1 principles of ADSL
1. ADSL Principle
ADSL-asypolicric Digital Subscriber Line, asymmetric digital user line. ADSL uses DMT modulation and asymmetric data transmission for business transmission. The uplink frequency is 26 kHz-138 kHz, the maximum transmission rate is 640 kbit/s, the downlink frequency is 138 kHz-1.104 MHz, and the maximum transmission rate is 8 Mbit/s, asymmetry means that the uplink and downlink speeds are different.
2. How the client obtains the IP address
Terminals can obtain IP addresses in the following ways:
1 fixed IP address (Manual Static configuration)
2. PPP (Point-to-Point Protocol) Protocol Negotiation
3. Automatic DHCP Configuration
3 DHCP + principle, pppoe principle, and features of the CNC @ CNC account
With the expansion of the network scale and the improvement of network complexity, the network configuration becomes more and more complex. Computer location changes (such as hosts or wireless networks) and the number of computers exceeds the allocable IP address. Dynamic Host Configuration Protocol DHCP is developed to meet these needs. In DHCP + mode, the IP address is assigned to the NIC.
Pppoe (Point-to-Point Protocol over Ethernet) uses Ethernet to connect a large number of hosts to the Internet through a remote access device, and implements the control and billing functions for accessing hosts, it has a high cost-performance ratio. With pppoe, multiple hosts over the same Ethernet can be easily connected to the remote server to establish a PPP session with the remote device for access control and billing. Users using PPP access can use the PPP address negotiation function. The Access Server assigns an IP address to the PPP session rwpppoe instead of the NIC.
The CNC @ CNC under pppoe is not restricted. It is not limited by the number of Internet ports, accounts, passwords, and client programs. You can download the client, it can be used to troubleshoot account errors.
4. Attenuation
Line transmission attenuation
ADSL works in the DMT modulation mode. the DMT-discrete multi tone modulation and discrete multi-tone modulation technology can be understood as simultaneously transmitting information through different frequency carrier channels, the DMT receiver receives all the channels at the same time and demodulation the information carried by each carrier. DMT uses an integer multiple frequency of 4.3125khz as the sub-carrier. Each sub-carrier is based on the signal-to-noise ratio (greater signal-to-noise ratio indicates that the smaller the noise in the mixed signal, the higher the signal transmission quality. Otherwise, the opposite is true) the size of the modulated 0-15 bits. The operating frequency ranges from 26 kHz to 1104 kHz, with a total of 256 channels.
When the line attenuation value is greater than 60 dB, the Internet cannot be accessed.
When the line attenuation value is between 50db-60db and the line Quality fluctuates, when the attenuation value suddenly exceeds 60db at a certain moment, the Internet cannot be accessed. When the line attenuation value is restored to 50db-60db, you can access the Internet again. Therefore, in the customer's view, the line is unstable and often dropped.
Therefore, we should try to select a line with a attenuation value below 50 dB so as to ensure the normal use of the customer.
5. Noise Threshold
Noise margin, also known as noise margin, is an "SNR margin" in the big Asian technology cat. The larger the value, the higher the line's Interference tolerance capability, reflecting the more stable the connection rate, the less likely to be disturbed. Note that the value of the upstream noise threshold and the downstream upstream noise threshold cannot be too different; otherwise, the uplink noise threshold may also be dropped, for example, 8 dB for uplink and 30 dB for downlink, it indicates that there is a problem with the line quality. Although the downstream signal is normal, but due to the problem with the upstream signal data, in pppoe mode, the fault is that the cat signal is normal, but frequent disconnection occurs, you can change the line. In addition, after the upgrade, the cat's signal lights seldom flash, and only rely on the status lights to determine whether the line quality is good, no longer accurate, and for this reason, the difficulty of handling line faults also increases significantly.
6. Fast and interleave)
If there is a continuous transmission error caused by noise on the line, it will be dispersed into the data in various fast modes. The data in the fast mode can generally handle these errors. If the line is very bad, you can increase the error correction capability by adding an intertwined processing method. of course, the larger the intertwined depth, the stronger the capability to ensure the stability of the line. The fast mode is faster than the intertwined mode, but the intertwined mode is better suited to harsh line conditions than the fast mode. Therefore, when the customer's line is poor, we can try to change the data center's fast mode to the intertwined mode.
7 Maximum accessible Rate
The maximum achievable rate is calculated based on the signal-to-noise ratio (SNR) obtained during connection training. This indicates the maximum rate that the line can reach and indirectly reflects the quality of the line.
8. Actual uplink and downlink speeds
If 2 m is enabled for the customer, but the actual speed is only more than 1 m, this may be due to a problem with the customer's line.
Part 2 common ADSL operations
1. Check that the network connection (NCPA. CPL) is configured with a fixed IP address and the IP address is automatically obtained.
(Omitted ).
2. Configure and view Internet Options (inetcpl. CPL)
After successful dialing, if you still cannot access the Internet normally, check whether the proxy server of the browser (IE) is set correctly. Set it to not use the proxy server; and try to log on to multiple websites, to confirm that it is not caused by a website server fault.
3. Start the New Connection Wizard command
Click "start" --- "run" --- "open", and enter (or copy and paste ):
Rundll32.exe netshell. dll, startncw
Click "OK ".
4. download and install the client and configure it.
Win98, me, 2000, cannot download and install the 256 client from the Internet. You must copy the 256 client to your computer. If the 256 client does not work, use the Ethernet 300 software.
Vista customers need to call 2614582 so that data center staff do not force clients to do data ". Note that 32-bit Vista can be used, but 64-bit Vista cannot be used due to its defect.
WINXP can download and install the 256 client from the Internet.
Click Start"
--- "Program" (or "All Programs ")
--- Attachment
--- Communication
--- New Connection Wizard
--- Next step
--- Connect to the Internet
--- Next step
--- Manually set my connections
--- Next step
--- Connect with a broadband connection that requires the user name and password
--- Next step
--- ISP name, enter "6"
--- Next step
--- Username, enter "CNC @ CNC ",
The password is "CNC ",
Confirm the password is "CNC ",
Both the username and password are in lowercase. @ indicates the number 2 and @ indicates the email,
--- Next step
--- Select "add a shortcut to this connection on my desktop"
--- Click "finish"
--- Search for "6" on the desktop"
--- Double-click "6"
--- Directly click "Connect"
--- When it indicates "registering a computer on the network... 6 already connected... "
Indicates that it has been connected.
--- Open your browser and enter "218.29.0.252" in the address bar"
--- Download the third item: double-stack client software (version 256, if the download is unavailable, the prompt "not a valid Win32 program" will be downloaded several times, you can only download a maximum of seven times.
5. View IP addresses using ipconfig
How to obtain an IP address through a PC
On a PC (DHCP client), you must first release the old IP address and then obtain the new IP address.
Release old IP Address
Different Operating System commands may be different. You can use either of the following two methods.
Use the ipconfig/release command in Windows XP Windows dos on your PC to actively release the IP address;
On the Windows 98 GUI, run [winipcfg/release] to release the IP address. The user's PC sends the dhcprelease message to the DHCP server.
The IP address is only the address of the host at the network layer. To send the datagram transmitted at the network layer to the target host, you must know the physical address of the host. Therefore, the IP address must be resolved to a physical address. Users do not want to use hard-to-remember IP addresses, but prefer to use easy-to-remember host names. Therefore, you also need to resolve the host names to IP addresses. The host's physical address is the MAC address. The DNS server performs the resolution of host names to IP addresses, while ARP performs the resolution of IP addresses to MAC addresses.
Apply for a new IP Address
Different Operating System commands may be different. You can use either of the following two methods.
Use the ipconfig/Renew command to apply for a new IP address in Windows XP Windows2000 dos on your PC;
On the Windows 98 GUI, run [winipcfg/update] to apply for a new IP address.
The user's PC sends the dhcpdiscover packet to the DHCP server.
Update IP address lease
Different Operating System commands may be different. You can use either of the following two methods.
Use the ipconfig/release command to update the IP address lease in Windows XP Windows2000 dos on your PC.
On the Windows 98 GUI, run [winipcfg/update] to update the IP address lease.
6. Use the ping command
If you think that the network is often disconnected, use the following method to test:
Click "start" --- "run" --- "open", and enter (or copy and paste ):
CMD/K Ping www.zz.ha.cn-T
Click "OK ". If
Reply from 125.46.61.130: bytes = 32 time = 41 Ms TTL = 58
Is normal.
If it appears frequently: Request timed out.
It is abnormal.
7 go to Daya technology DB108-G modem to view system information
Change the IP address of your computer Nic to the same network segment, that is, 192.168.1.10.
Set the network adapter TCP/IP Protocol IP address to 192.168.1.10.
Mask: 255.255.255.0
Gateway: 192.168.1.1
You must set a gateway!
Use http: // 192.168.1.1!
Username: Admin
Password: Admin
Display status
If you enter 192.168.1.1 in the address bar, the page cannot be displayed. If you cannot enter modem, press rst on the cat and enter 192.168.1.1, the setting page of the cat is displayed. Or shut down the computer and the cat and re-open it.
After entering the interface, you can view "system information-ADSL information:". You can view the following four parameters:
Speed: Above 1800 is normal. If the value is small, it is often related to the line quality.
Channel: interleave or fast. If the line quality is poor, change fast To interleave in the data center.
Attenuation: the downlink value is less than 60. If the value is greater than 50, the signal is poor, which is often related to the line quality.
SNR margin: The noise threshold. The larger the value, the better.
8 view line quality with dlink DSL-200 usb modem Test System
After installing the driver for the usb modem, click "start", "program", "D-link DSL-200", "DSL-200 control panel", press Alt + P, display the following test system, or use autolog to view all parameters.
Bitmap
Click "bit loading" under "Physical Layer Statistics". We know that the line parameters in the same junction box or junction box are close, so how can we use bitmap as an important basis for line quality screening?
Based on actual experience, the more green bars, the more stable the graphics center of gravity of the entire Green module, the better the line quality, and the more stable the internet.
In the middle, the blue part is the ADSL upstream data transmission channel, the green part is the ADSL downstream data transmission channel, and the telephone call voice part occupies the first channel, which is omitted in the figure. The gaps in the blue and green sections are used to facilitate the separation of upstream and downstream data from the signal.
Standard bitmap:
Fault bit diagram:
9. Change the password, unbind, and clear online users using the Alibaba Cloud account system.
If you open the http: // 221.13.223.152: 7001/lcbms50 page, the window will suddenly be closed. Account: zm028011
10 install the enternet 300 dialup program in WIN98 and winme Systems
Enternet 300 broadband dialing program download
(If you have a problem using the 256 broadband dial-up program, or you suspect that the XP built-in dial-up system has a problem, you can use the dial-up program to check using the account of the CNC @ CNC)
Http://bbn.zmdip.com/e300.exe
Installation instructions for the software:
Http://www.pcdog.com/tech/html/2004917/17920049745_1.htm
11 use a speed test website
If you think the network speed is slow, please use the following URL for speed testing!
Http://test.zmdip.com
Download or run the file. If it is more than kb, it is normal... If it is too low, it is easy to drop the line, or the network card is faulty.
12. Be familiar with important error information and Corresponding Handling Methods
When pppoe is used, many error messages are often prompted when the customer fails to access the Internet. Sometimes there are different error prompts for the same fault cause, and sometimes multiple dialing times, every error prompt is different, which requires us to be diligent in thinking and understanding. Pay attention to carefully analyzing the real fault causes behind these error prompts:
For example, if the NIC Driver is abnormal, there is a yellow exclamation mark or a cross in the Device Manager, and an error 769 is prompted. Sometimes the 769 error is prompted if no cross is displayed on the NIC icon, enable the NIC again.
Error 619 or 691. If it is a new cutover user, unbind it.
Of course, more detailed error information help and guidance, click "start" ---- "Help and Support" in WINXP system. Enter "error message" in "Search" or enter code such as "678" or "619 "., you can get detailed error information and solutions. Of course, you can get more detailed and accurate help and guidance on the Internet in "Microsoft knowlebase" at the bottom of the search bar.
13. Configure the broadband DVD (before configuration, make sure you have bound the MAC address. For the broadband king, because it is not cutover, the data center also needs to make the DVD account into the broadband King account .)
Power on the set-top box, and press the "Network Settings" button on the remote control:
(The old-fashioned set-top box is to turn off the network DVD power and switch the configuration to the "Settings" file .)
1. Enter the password (20040218) on the keyboard and press OK to wait for the network DVD to automatically restart.
2. After the device is restarted, the parameter settings page is displayed. (Note: if the parameter settings page appears when the device is started for the first time, you can directly go to the following configuration steps)
3. In the "ESMs server" column, enter the IP address of the Entry Server: 218.28.102.10;
4. Select "pppoe" in the "connection" column ";
Note: Do not fill in the "Proxy Server" column
5. Click "Next ";
6. Enter the username @ IPTV. HA and password, and click "save". After the network DVD is restarted, after checking that the ESMs Server IP address is correct, click "Submit;
7. Press the submit button to display the prompt "connect to pppoe server" and "successfully log on to pppoe network.
8. Turn off the network DVD power and switch the configuration to the "running" file.
Note: The configuration switch can only be changed when the power supply is disabled.
9 turn on the network DVD power, the network DVD will enter the service page.
14. How can I check and repair the broadband line without using other testing instruments?
Work und: You can change the main, wiring, room and external line, indoor line, modem, separator, and network cable.
First, you can determine which segment of the region belongs to the poor part of the line based on the usual experience in maintaining the fixed phone. For example, if there is a problem with the trunk cable, there is a problem with the wiring cable, and there is a problem with the junction box, broadband line problems also occur in areas where these lines are prone to problems. Line connection rust, damp, squeezed, twisted wire, ground gas and other problems will lead to problems with the customer's use of broadband. Comprehensive Analysis and inspection of fixed telephone line faults to provide customers with high-quality line quality. In this way, the accumulated rich line processing experience will be applied to broadband installation and maintenance.
Secondly, if conditions are met, you can use the segment exclusion method to check the line, find a place with AC power supply near the junction box, and mount the modem to test whether the status light is normal, you can also test the modem at The binning box, or open the indoor line, and pull a temporary line for testing. This makes it easy to locate the fault during the segmentation check.
Third, use the network management equipment of the data room for testing. Because the network management equipment has the function of checking the line quality and providing the line test parameters, you can contact the staff of the data room after replacing the line, check whether the line quality meets the broadband activation requirements.
Fourth, for line faults that are difficult to judge, you can switch with other lines used by normal customers nearby for observation and fault detection.
15 use the Device Manager (sysdm. CPL) to disable and enable the NIC
Click "start" --- "run" --- "open", and enter sysdm. Cpl.
Click "OK ".
Select "hardware", "Device Manager", "network adapter", right-click the network adapter, and choose "Disable" or "enable ".
16 disable the firewall that comes with WINXP
Disable Internet Connection Firewall in Windows XP or Windows XP SP1
Note: The purpose of the firewall is to help your computer defend against attacks by malicious users or software. Malware includes viruses that attack your computer using unsolicited incoming network communication. Before disabling the firewall, you must disconnect the computer from all networks (including the Internet ).
To do this, follow these steps:
1. In "Control Panel", double-click "network and Internet connection", and then click "network connection ".
2. Right-click the connection to disable ICF and click "properties ".
3. On the "advanced" tab, click to clear the "Protect my computer or network" check box.
Disable Windows Firewall in Windows XP SP2
Follow these steps:
1. Click Start, click Run, type firewall. CPL, and then click OK ".
2. on the "General" tab, click "close (not recommended)", and then click "OK ".
17. Set up a broadband private proxy
Enable the Internet connection to share pppoe over the pppoe Broadband Network
1. In "Control Panel", double-click network connection.
2. Click the pppoe connection you want to share under the "Broadband" group, right-click, and select "properties ".
3. On the Advanced tab, click to select the "allow other network users to connect to this computer over the Internet" check box.
4. pppoe connections are similar to Dun connections, and you may want another computer on the network to enable automatic dial-up when trying to connect to the Internet. To do this, click to select the "Create a dial-up connection when a computer on my network attempts to access the Internet" check box.
5. If you want to allow other network users to enable or disable shared Internet connections, click to select the "allow other network users to control or disable shared Internet connections" check box.
6. in Internet Connection Sharing, in "Home Network Connection, click the computer that has shared its pppoe Internet connection with other computers to connect to the LAN (LAN) Connection of other computers on the network.
Note: When you select a connection to be shared, the connection must be an external connection that can connect the ICS host to the Internet. Selecting the wrong connection will make ICS unable to work.
Note: To enable ICS in Windows XP, you must have administrative permissions.
Note: When ICS is enabled, the network adapter connected to the home network or small office network receives a new static IP address 192.168.0.1 with its subnet mask 255.255.255.0.
15. Broadband website
After upgrading to the pppoe system, many customers realized that they did not save the new version of the client or did not use the CNC @ CNC to directly download it. When the customer does not understand the computer, our staff needs to download the Client Multiple times or instruct the customer on the phone for complicated operations, which is time-consuming. Therefore, you can create the following broadband help webpage to notify the customer of the broadband fault when installing the broadband for the customer or by phone, so that the customer can open it on the computer where the customer can access the Internet, it is easy to solve the problem. The actual use is superior.
URL: blog.sina.com.cn/unik
Part 4 fault analysis Diagram
There are many failures in broadband, and customers cannot access the Internet normally due to exceptions at any location.
Part V troubleshooting Flowchart
Error: the account has been connected. It is very slow to open the webpage or cannot open the webpage.
If your account has been connected, it is extremely slow to open the webpage. Ping the website and the packet loss is severe. You can only open the website for a few minutes. Use the test port in the measurement room to test whether the data center port is faulty. The main faults are:
Code 678
Error 678, cause:
The most common faults may be line problems, user system problems, modem problems, or data center port problems.
Solution: Use exclusion
1. Eliminate the modem problem: restart the modem and the computer, and try to restart the modem repeatedly. The power supply time of the modem is no less than 30 seconds each time. If the problem is resolved at the end, continue to the next step.
2. Eliminate user port problems: contact the measurement room to test whether the user port is normal from the distribution frame. It should be noted that, for many users with poor line quality, modem lights will still work normally. Therefore, when testing the user port in the measurement room, you must not only check whether the modem lamp is in normal state, but also connect to the computer and log on with the test account to determine whether the modem lamp is actually normal. If the measurement room port is normal after testing, the fault can be basically locked in line and user system problems.
3. Eliminate line problems: contact the data center to check the line quality of user ports from the network management system, and the maximum accessible rate. If the quality of the line is abnormal, check the program of the line, check the contacts from the inside out, and find the fault point to fix. If the line is normal, it is a user system problem.
4. user system problems: (1) Windows 98 and Windows 98 are common faults. Try to install other dial-up software (the data room must be removed from the mandatory client ).
(2) In the XP system, you can create a broadband connection. The account uses the CNC @ CNC password to test whether the connection can be established. ① if the connection is normal, it indicates that the Netcom client has a problem, you can simply uninstall and reinstall it, but you cannot use the broadband connection provided by XP to access the Internet (you need to remove the mandatory client from the data center ). ② Unable to connect normally. Try again as follows: Detach the network adapter from the Device Manager and reload it again.
5. If all of the above attempts and detection are successful, and the problem has not been solved, use your laptop to test the Internet connection. We recommend that you reinstall the system.
Supplement: Sometimes, the user line in the data room is not good. For example, if the maximum accessible rate is kb, the test port in the measurement room can be logged on normally, but the self-built laptop cannot access the network. At this time, it can still be determined that the line quality is poor. Sometimes, reactivate the data port can solve this problem.
Error: The system prompts that the account has been logged on.