When locating a flashing alarm fault, the first concern is whether low optical power is the cause.

Products

OptiX OSN7500

Fault Category

Other

FCS_ERR

ALM_GFP_dLFD

IN_PWR_ABN

Phenomenon Description

A telecom network topology is A-B-C-D-E-F-A, where A is an OSN 7500 device and the others are 155/622 devices to realize two-fiber bidirectional MSP ring protection. Network element A 's 18-N2EFS0 and network element C 's 6-EFTO4 open data services. On a certain day, the 18-N2EFS0 board of Network Element A keeps flashing FCS_ERR and ALM_GFP_dLFD alarms, and the 6-EFTO4 of Network Element C flashes LP_REI alarms, but the data services of both ends are normal.

Cause Analysis

Analyze the possible causes according to the phenomena as follows:

The parameter settings of the docking data boards are inconsistent.

Single board failure.

Optical power problem.

Procedure

Query the encapsulation protocols of Network Element A and Network Element C and find that the GFP encapsulation protocol parameters are the same at both ends.

Select the Ethernet board in the Network Element Manager and choose "Configuration > Ethernet Interface Management > Ethernet Interface" in the Function Tree.

Select "Internal Ports", and then select the " Encapsulation/Mapping " tab.

Click Query.

After consulting with the user, it is learned that the alarm occurs after the server room where Network Element B is located has been renovated.

Check the alarms and performance events of Network Element A and find that Network Element A reports IN_PWR_ABN and has a large number of error blocks. Therefore, it is judged that it may be caused by low optical power.

Query the received optical power of Network Element A as -29.4 dbm, which is close to the sensitivity of -30 dbm. reverse the service between Network Element A and Network Element C to the alternate channel, and the alarm can disappear.

Check the site of network element B, found that the fiber on the ODF side is loose, after tightening the optical power test is normal, the alarm disappears.