After the service runs stably for a period of time, with observation, it is found that the input optical power of this WPA board of station B is decreased 3dBm again. Measure the input optical power of the variable attenuator from station B and compare the value with previously recorded value, the value is decreased about 3dB, indicating that the input optical power of the variable attenuator is decreased 3dB, therefore, we can judge that the variable attenuator and WPA board of station B are in normal operation. Apparently, the fault is in the range from the output port of WBA board in station A to the variable attenuator of station B. Directly measure the output optical power of WBA board in station A, there are few changes, indicating that the problem is on either the fiber jumper or optical path from OptiX BWS 320G equipment of station A to ODF frame.
Measure and check the fiber jumper from OptiX BWS 320G system to ODF frame in station A, it is found that the section of fiber jumper is squeezed, resulting in large attenuation. After the fiber jumper is straightened, normal operation is resumed, and the fault does not appear any more.
& Note:
Since SDH equipment employs bi-directional multiplex section mode for networking, during testing optical power as described in the above steps, if the input fiber jumper of WPA board in station B is disconnected, self-healing protection switching happens in SDH equipment, and service is just affected slightly.
3. Experience and summary
Analyzing the performance data of OptiX BWS 320G system is an effective measure for fault localization, but signal flow should first be known well. The general sequence of fault localization is: first locate the faulty section, and then find the faulty point by testing point by point.
2.2 ECC Problems
OptiX BWS 320G system employs the optical supervising signal with the wavelength of 1510nm and the rate of 2Mbit/s. D1- D3 bytes in the monitoring signal are used for OAM information exchange between NEs. On SCC unit, there are several SCC serial ports dedicated for DCC byte processing, and each SCC serial port corresponds to a 192kbit/s DCC channel.
The communication between NM and non-gateway NEs is implemented in this way: first information is transferred between NM and gateway NEs through TCP/IP protocol, and the communication between gateway NEs and non gateway NEs is implemented through ECC, thus the communication between NM and non gateway NEs is accomplished.
2.2.1 Common Causes of ECC Faults
(1) Power supply faults, such as equipment power failure, the voltage of power supply is too low and so on.
(2) Optical fiber faults, such as optical fiber performance deterioration, excessive attenuation or broken fiber.
(3) SCC unit fault.
(4) SC1 or SC2 board fault.
(5) A great number of performance data from NEs are reported to NM, causing ECC channel to be blocked.
2.2.2 Common Methods
(1) Alarm and performance data analyzing method.
(2) Resetting board.
(3) Substitution method.
2.2.3 Procedures
Step 1: exclude external factors by analyzing the performance data of SC1 and SC2 boards, such as power failure, broken fiber, optical fiber performance deterioration, etc., any one of them will affect service over an extensive area, and the fault symptom is not just that ECC is blocked. Therefore, optical path fault can be excluded.
Step 2: first reset SCC unit of the faulty station. If the logging in operation still fails, unplug the SCC unit to enable ECC to get through, and see whether the downstream NEs can be logged in; if not, the problem might be on SC2 or SC1 board, replacing the SC2/SC1board.
Step 3: if the downstream stations can be successfully logged in at Step 2, check or replace the SCC unit of home station.
Уважаемый посетитель!
Чтобы распечатать файл, скачайте его (в формате Word).
Ссылка на скачивание - внизу страницы.