Troubleshooting[NE40E]: The Physical Status of POS Interfaces Cannot Go Up

Common Causes

This fault is commonly caused by one of the following:

•  Interfaces at both ends of the connection are shut down.
•  The optical module specification is incorrect or the link is faulty.
•  Synchronous Digital Hierarchy (SDH) alarms are reported at both ends of the connection.
•  The fiber is not properly connected.
•  The fiber is inserted into the transmit optical port/receive optical port of the optical moduleon one end but is inserted into the receive optical port/transmit optical port of the opticalmodule on the other end.
•  The board or the optical module is faulty.

Troubleshooting Flowchart

When POS interfaces of two NE80E/40Es are connected, the physical status of POS interfacescannot go Up (indicating that the interfaces cannot connect).
The troubleshooting roadmap is as follows:

•  Run the undo shutdown command to check whether configurations of the local device arecorrect.

•  Check the fiber, optical module, and board on site.

Troubleshooting Procedure

Step 1 Check whether interfaces at both ends of the connection are shut down, the transmit/receive optical power is normal, or if SDH alarms are reported on the interfaces at both ends of the connection.

Run the display interface pos [ interface-number ] command. Depending on the displayed information, check the following items: 

- If the current field state is "Administratively down", it indicates that the POS interfaces are shut down. In this case, run the undo shutdown command in the POS interface view.
- If the transmit optical power is not within the normal range, the optical module needs to be replaced.
- If the receive optical power falls below the receiver sensitivity of the optical module, adjust the link or replace the optical module.
- If the SDH alarm field indicates a value other than "none" and the SDH error fields indicate increase in the number of B1, B2, or B3 error codes:
– Increase in the number of B1, B2, and B3 error codes: Check the transmission stability of the link (including optical modules at both ends of the link) between the router and the SDH transmission device. If the direct link is a WDM link, check the transmission stability of the WDM link.
– Increase only in the number of B3 error codes: This problem occurs when the router and the SDH transmission device are directly connected through a link. In this scenario, check the transmission stability of the direct link. If the direct link is a WDM link, check the transmission stability of the WDM link. If the fault persists, go to Step 2.

Step 2 Check whether the optical modules or the fiber is properly connected. Both the optical module and the fiber have card fasteners. If a "clap" sound is heard during the insertion of the fiber or the optical module, the fiber or the optical module has been properly inserted. If the fault persists, go to Step 3.

Step 3 Check whether the two ends of the fiber are inserted into correct optical interfaces. Remove the fiber and then change the optical interface into which one end of the fiber is inserted; for example, if one end of the 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 corrected, it indicates that the two ends of the fiber are inserted into the incorrect optical interfaces. If the fault persists, do not change the optical interfaces into which the two ends of the fiber are inserted; instead, go to Step 4.

Step 4 Perform the loopback test on the local fiber.
Use a fiber in good condition to connect the transmit optical interface to the receive optical interface of the local optical module:

- If the physical status of the two interfaces goes Up, all SDH alarms on the interfaces are cleared and the number of B1, B2, or B3 error codes is not increased. It can therefore be concluded that the board and the optical module on the local device are normal. Check the link or the peer device.
- If the physical status of the two interfaces remains Down, it can be concluded that the board or the optical module of the local device is faulty. Replace the board or the optical module, or cut over services on the faulty interface to another interface that runs normally. 

Step 5 Collect the following information and contact Huawei technical support personnel.

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