High Bit Error Rate in DWDM channel
Hi ,
Dear Community , today I have a case related of a High Bit Error Rate in DWDM channel.
Description
-We have a DWDM network of OSN 6800 equipment , the network has many services different in their distances .
- For 10G services we often use LSX as a Transponder board to make frequency adjustment & FEC processes for the client signals , But for the short distance links , we use a Colored XFP which can be easily plugged in the SDH or Routers boards to produce the service signals in a defined DWDM lambda .
-One of the 10G used for SDH raises high Error ( RS_BBE , HP-BBE )
The troubleshooting steps
- We started with replacing the Colored XFP in the SDH SL64 board , but the error persisted .
-As the performance of laser from the XFP is not so high and the distance from the source to the sink NE was about 90km , we thought of checking the OSNR value for that signal using OSA ( Optical Spectrum Analyzer ) , We found that the OSNR is about 18 which is not accepted when using Colored XFP .
DWDM Tuneable XFP
Board Manufacturer information for SL64
-you can check the Colored XFP information like distance , lambda and SN from the ((Board Manufacturer information)) .
The solution
- We had to replace the colored XFPs in the SL64 boards with Gray XFPs and to use LSX boards in the source and sink NE to enhance the signal OSNR and to get good signal.
-After installing the LSX and swapping the traffic , the alarm of the error got cleared and problem solved .
Conclusion
-The Colored XFPs gives weak quality DWDM signals in terms of OSNR and optical signal parameters like SMSR , width at 20db , while LSX provide a very high signal quality supporting a variety of signal coding like (NRZ , RZ , DRZ , ODB ) and high extraction capability for the received signal that allow to receive signal with up to 14 OSNR value .
Also LSX supports FEC & AFEC which enhance signal quality and prolong transmission distance.
Therefor transponder boards must be used for long transmission distance and colored XFP can be used only for the very short links.
welcome to read and feedback
