Cause analysis
The possible causes of the fault are as follows:
- Hardware of the TN12TDX, TN12XCS, TN11ND2, or the backplane of the subrack is faulty.
- Communication on the TN12XCS fails, and therefore the cross-connection configuration fails to be delivered to the TN12XCS.
- The line rate modes configured for the tributary and line boards on the system side are inconsistent.
Procedure
- Query alarms on the NE. It is found that all NEs and all tributary and line boards configured with ODU2 cross-connections report the BUS_ERR alarms. The BUS_ERR alarms on certain NEs or boards last for a certain period and then end.
The fault occurs on the same type of boards at different sites or on different NEs, and the probability of a hardware fault is small. The most probable cause of the fault is a configuration fault. - Select a TN12TDX board and a TN11ND2 board that report the BUS_ERR alarms for analysis. Query their service configurations, and it is found that the Service Type of TN12TDX is defaulted by None and the Service Mode of the TN11ND2 is set to ODU2.
On the network shown in the previous figure, the Service Type of the TN12TDX is None and the service rate on the system side is 11.1 Gbit/s (in both transmit and receive directions), but the Line Rate of the TN11ND2/TN12NS2 is set to Standard Mode. That is, in the case of the TN11ND2/TN12NS2, the service rate on the system side is 10.7 Gbit/s in both transmit and receive directions. Therefore, the transmit/receive rates of ODU2 services of the tributary and line boards on the system side are different. It is found that the boards report the BUS_ERR alarms after detecting incorrect ODU2 frame signals. The transmit/receive rates of ODU2 services of the tributary and line boards on the system side are different, and therefore the BUS_ERR alarms are reported.
Result
After the Line Rate of the TN11ND2/TN12NS2 is set to Speedup Mode, the BUS_ERR alarms are not reported.
The problem is resolved.
Reference Information
Conclusions and suggestions for this case are as follows:
In the case of the OptiX OSN product series, all tributary and line boards that support ODU2 cross-connections support the preceding two rate modes, and therefore the rate modes of the tributary and line boards must be consistent. Otherwise, the boards report the BUS_ERR alarms and services cannot be provisioned.
