This section describes the inband DCN faults in terms of the symptoms, impact on the system, possible causes, tools required for troubleshooting, troubleshooting procedure, and precautions that should be taken during the troubleshooting.
Prerequisite
You must ensure that each board on the NE is of the mapping version by checking the engineering document.
Symptoms
The symptoms of the inband DCN faults may be as follows:
l The communication between the T2000 and the NE is interrupted. The NE icon on the
T2000 is grey, and the NE is unreachable to the T2000.
l The operations on the T2000 are not responded. If the response interruption time lasts for
more than two minutes, the communication between the T2000 and the NE is interrupted.
l When you query certain information on the T2000, the query result contains incomplete
Troubleshooting Flowchart
Figure 3-7 shows the flowchart for troubleshooting the inband DCN faults. Figure 3-7 Flowchart for troubleshooting the inband DCN faults
Start
Whether the NE icon turns
grey
Whether fault is rectified
End Contact Huawei technical
engineers
No
Yes The system control
board is restting The communication between the T2000 and
the NE is interrupted Yes Enable the DCN port No Whether the T2000 query information is lost Whether the T2000 operation command is not responded Whether the physical connection is interrupted Reconnect the network cable or optical fiber Whether the DCN port is disabled Whether the receive signals
are lost Yes No No Whether the board is faulty
Replace the board No
Handle the alarms related to the optical
power, fibers, and cables
The bandwidth configured for the DCN
tunnel is too small Yes Yes No Yes Yes Yes
Increase the bandwidth configured for the inband
DCN tunnel
Wait until the reset of the system control
board is complete
Impact on the System
l When the NE fails to communicate with the T2000, other NEs that communicate with the
T2000 through this NE become unreachable to the T2000, if they cannot be connected to the T2000 in other manners. The other NEs are not affected.
l If the physical channel that carries the inband DCN is faulty, the other services carried in
this physical channel are affected.
Possible Causes
As shown in the troubleshooting flowchart, the inband DCN faults may be due to the following causes:
l Cause 1: The physical connection between the faulty NE and the T2000 is interrupted. l Cause 2: The inband DCN port of the faulty NE is not enabled.
l Cause 3: The received signals of the faulty NE are lost, or the received optical power is
excessively low, and thus the DCN packets cannot be extracted.
l Cause 4: The board is faulty.
l Cause 5: The bandwidth configured for the inband DCN channel is excessively small. l Cause 6: The board on the faulty NE is being reset or the active/standby switching of boards
is performed, and thus the inband DCN packets cannot be responded.
Tools, Instruments, and Materials
T2000
Precautions
CAUTION
Before locating the faults, you should check whether each board on the NE is of the mapping version. If a board is not of the mapping version, replace the board in time.
NOTE
When handling the inband DCN faults, perform the following operations:
l If the NE communication is interrupted, you should handle the faults of the gateway NE, and then handle the faults of the non-gateway NEs.
l If the NE communication is not interrupted, handle the faults of the non-gateway NEs first, and then handle the faults of the gateway NE. Hence, the non-gateway NEs are prevented from being unreachable to the T2000.
Procedure
l Cause 1: The physical connection between the faulty NE and the T2000 is interrupted. 1. Check whether the network cables or fibers of the faulty NE are disconnected from
the ports. If the network cables or fibers are disconnected from the ports, insert the network cables or fibers again.
l Cause 2: The inband DCN port of the faulty NE is not enabled.
1. Check whether the ports, which support the DCN function by default, are connected with the fibers or cables. If not, change the present port to a port whose DCN function is enabled by default. Availability provides the information about the ports of OptiX RTN 950 whose DCN function is enabled by default.
2. Check whether the ports at the two ends of the link are enabled. If not, enable the inband DCN port. For details, see Enabling the Port DCN in the Feature
Description manual.
l Cause 3: The received signals of the faulty NE are lost, or the received optical power is excessively low, and thus the DCN packets cannot be extracted.
1. Check whether the ETH_LOS, or IN_PWR_ABN alarm exists on the board configured with the inband DCN channel. For details, see 8.2 Querying Current Alarms of a Board. Clear these alarms.
l Cause 4: The board is faulty.
1. Check whether the HARD_BAD alarm exists on the board configured with the inband DCN channel.
2. If the alarm exists, replace the board that reports the alarm. For details, see 5 Replacing Components.
l Cause 5: The bandwidth configured for the inband DCN channel is excessively small. 1. When the number of services configured on the port exceeds a certain number, part
of the query information may be lost. In this case, you should properly increase the bandwidth configured for the inband DCN channel. For details, see Setting the VLAN ID and Bandwidth Used by an Inband DCN in the Feature Description manual. l Cause 6: The board on the faulty NE is being reset or the active/standby switching is
performed, the inband DCN packets cannot be responded.
1. Observe whether the PROG indicator on the system control board is blinking in green. If the indicator is blinking in green, it indicates that the system control board is in the reset state. After the PROG indicator is always on in green, the reset of the system control board is complete and the DCN connection is automatically recovered.
NOTE
If the active/standby switching occurs on the system control board, a warm reset is performed on Active Board.
2. If the DCN response does not recover, check whether the protection switching occurs on other boards. If other boards are switched, the inband DCN packets are in the rerouting state. For details, see 8.23 Querying Protection Configuration.
3. If the protection switching occurs on the boards, after the DCN rerouting is complete, the response is automatically recovered.
l If any problems occur during the troubleshooting, contact Huawei engineers. For the contact information, see 3.15 Fault Notification and Technical Support.
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