Troubleshooting Flowchart

The troubleshooting roadmap is as follows:

Troubleshooting Procedure

 NOTE:

After the commands are configured to troubleshoot the faults, check the configuration validation mode to ensure that the configurations take effect. Unless otherwise specified, this manual defaults to immediate validation mode.

• In immediate validation mode, the configurations take effect after the commands are entered.
• In two-phase validation mode, after the commands are configured, the commit command needs to be run to commit the configurations.

Save the results of each troubleshooting step so that if your troubleshooting attempts fail to correct the fault, you will have a record of your actions to present to Huawei.

Procedure

1. Check whether the POS interface at each end of the link is shut down, whether the transmit/receive optical power is normal, or whether SDH alarms exist on the POS interfaces.

   To check the preceding items, run the display interface pos [ interface-number ] command (The following example uses the command output on one POS interface):

   • If current state is Administratively down, the POS interface is shut down. In this case, run the undo shutdown command to start up the POS interface in the POS interface view.
   • If the transmit optical power (Tx Optical Power) is not within the normal range, replace the optical module.
   • If the receive optical power (Rx Optical Power) falls below the receiver sensitivity of the optical module, adjust the link or replace the optical module on the peer device.
   • If SDH alarm is not none and either of the following conditions occurs in the SDH error field:

     • The number of B1, B2, and B3 bit errors keeps increasing: Check whether the directly connected link between the router and optical modules at both ends of the link are stable. If the link is a WDM link, check the transmission stability of the WDM link.

     • Only the number of B3 bit errors keeps increasing: This problem may occur when the router and the SDH transmission device are directly connected through a link. In this case, check whether the link between the two devices is stable. If the link is a WDM link, check the transmission stability of the WDM link.

   If the fault persists, go to Step 2.

2. Check whether the optical module is properly installed on the failed POS interface and whether the optical fiber is properly connected to the failed POS interface.

   Both the optical module and the optical fiber have card fasteners. The optical fiber and the optical module have been properly installed when a "click" is heard.

   If the fault persists, go to Step 3.

3. Check whether the transmit end and receive end of the optical fiber are correctly installed.

   Remove the optical fiber and reverse the transmit and receive ends of the optical fiber. Reinstall the optical fiber into the optical modules on the two interconnected device. If the fault is rectified, the two ends of the optical fiber were originally reversely installed.

   If the fault persists, restore original optical installation and go to Step 4.

4. Perform a loopback test on the optical fiber.

   Use an optical fiber to connect the local optical module's transmit optical interface to the receive optical interface:

• If the physical status of the two interfaces goes Up, all the SDH alarms on the interfaces are cleared, and the number of B1, B2, or B3 bit errors does not increase, the board and optical module on the local device are normal. Check the link or peer device.
• If the physical status of the two interfaces remains Down, the board or optical module of the local device fails. Replace the failed component, or switch the services on the failed interface to another normal interface. If the fault persists, go to Step 5.

  NOTE:

  When performing the local loopback test, set the interface clock mode to Master.

Remove the optical fiber and change the optical interface into which one end of the optical fiber is inserted. For example, if one end of the optical fiber is inserted into the transmit optical interface of the optical module, insert it into the receive optical interface of the optical module. If the fault is rectified, the two ends of the optical fiber are inserted into wrong optical interfaces.

If the fault persists, do not change the optical interfaces where the two ends of the optical fiber are inserted and go to Step 4.

• Results of the preceding troubleshooting procedure
• Configuration, log, and alarm files