Use of intelligent optical modules, network management unit can be real-time monitoring of transceiver module temperature, supply voltage, laser bias current, as well as transmit and receive optical power.The measurement of these parameters, you can help manage the unit to identify the location of the fiber link failure, simplify maintenance, improve system reliability.This article describes how to use the optical module of the digital diagnostic functions positioning system failure.
Digital diagnostic functions
SFF-8472 MSA specification digital diagnostic functions and SFF-8472 details.The specification states that the circuit board inside the module detection and digital parameter signal.Then, after calibration or digital measurement results and calibration parameters.This information is stored in the memory structure of the standard, in order to read through the dual-cable serial interface.The SFF-8472 to retain the original SFP / GBIC in the address A0h at the address mapping and address A2h new a 256-byte storage unit.In addition to the parameter detection information, the storage unit defines the warning signs or warning condition, the state of each pin image, limited ability to control the digital and user-written storage unit.
What is part of the information stored in the address space:
1) Real-time measurement parameters
Emitted light power Tx_power
Received optical power Rx_power
Temperature temp
Operates at Vcc
Laser bias Laser Bias
2) Alarm or alarm
Tx_faul
LOS measurement of the parameters of the alarm and the alarm flag
3) control flag
Tx_disable
Rate_select
The application of digital diagnostic functions
Troubleshooting features in the optical transceiver system provides a means of performance testing, system management can help to predict the life of the transceiver module, the failure of the isolation system and to verify the compatibility of the module in the on-site installation.
Module life prediction
This failure to predict that allows network managers to find potential link failure in the system performance affected. Failure notice, the system administrator can business to switch to the backup link or replace a suspicious device, which in the case of non-stop services to repair the system.
Only SFP provides a real-time parameter detection means of the laser degradation of a prediction.The optical module within the optical power feedback control unit will control the output power in a stable level, but with the aging of the laser, the quantum efficiency of the laser will be reduced.The power control is achieved by increasing the laser bias current (Tx_Bias).Therefore, we can predict the life of the laser through the detection of the laser bias current.This method can be a rough estimate of the life of the laser near the end.Temp and Vcc, laser bias current and module temperature and voltage have a relationship, so the need to consider when setting the bias current limit.
By real-time monitoring of transceiver module within the operating voltage and temperature, allowing the system administrator to find some potential problems:
1) the Vcc voltage is too high, will bring the breakdown of the CMOS device; the Vcc voltage is too low, the laser is not working properly.
2) accept the power is too high, can damage the receiver module.
3) The operating temperature is too high, will accelerate the aging of the device.
In addition, the received optical power monitoring, and can monitor the performance of the lines and the remote transmitter.
Fault location
In the optical link, locate the fault, an unknown critical to business fast loading. The fault isolation feature allows system administrators to quickly locate the position of a link failure. This feature can locate the fault line in the module; local modules or remote modules. By quickly locate the fault, reducing the repair time of system failure.
Fault status, a comprehensive analysis of the status bits, pins and measurement parameters.
In short, digital diagnostic functions, you can locate the fault.Fault location on Tx_power Rx_power, Temp, and Vcc, Tx_Bias, warning and alarm status of a comprehensive analysis.State variables in the memory mirroring Tx Fault and Rx LOS (loss of signal) on the failure analysis plays an important role.
Verified for compatibility
Another feature of digital diagnostic module compatibility verification. Compatibility verification is the analysis module of the working environment in line with the Data Sheet and the relevant standard compatible. Module performance can be ensured only in the work environment that is compatible. In some cases, due to environmental parameters beyond the data sheet or the relevant standards, will cause the module performance degradation, and thus transmission error.
Working environment and the modules are not compatible:
1) the voltage beyond the specified scope
2) the received optical power overload or below the receiver sensitivity
3) the temperature exceeds the operating temperature range
No comments:
Post a Comment