Problem description

OSN3500 network elements are interfaced with N company data veneer through EFT veneer, and LCAS_FOPT alarm is reported on EFT8 veneer after LCAS function is enabled with parameter 0x01 0x00 0x08 0xff 0xff. master version 5.21.16.13P04, EFT8 veneer version is matched with master version.

Alarm information

LCAS_FOPT

Processing

1, through the alarm of the third alarm can know the scene is VCTRUNK8 on the alarm;

2、Using the EFT8 single board LCAS information acquisition script to collect data, it can be determined that VCTRUNK8 binds five2M bandwidth, time slots are 21, 39, 42, 60, 63. However, when the single board receives the MST message sent from the opposite end, there are six channels marked with 0, which indicates that the channel belongs to the channel of the LCAS, and then the single board reports the LCAS_FOPT alarm. FOPT alarm.

3, further analyze the MST message received by the single board and found that the value of the 64th channel in the channel mark corresponding to the VCTRUNK alarm is 0, but in fact the 64th channel is not available at all. According to the specification of ITUT, all channels should be FAIL (marked as 1 ) in initialization, and the channel mark will be changed to 0 only when the CTRL message of the LCAS protocol adds a certain channel to LCAS, and the mark will be changed to 1 when the channel is released.

4. Check the MST messages sent by the EFT8 veneer to confirm that the veneer is sending correctly.

5. From this, it can be determined that there is no problem with the EFT8 single-board processing, and it is necessary for the customer to coordinate with the opposite end of the N manufacturer to solve the problem.

Root cause

1, OSN3500 LCAS_FOPT alarm detection is reported because the LCAS protocol received the number of channels marked as 0 in the MST message sent by the terminal equipment and the number of channels bound by VCTRUNK is inconsistent.

2. According to the alarm detection reporting mechanism, the message sent by the opposite end is incorrect or the EFT8 board detection error may generate an alarm.

Recommendations and Summary

None