One day, one of the DES-3200-28 B1 switches began to write the following in the logs:
412 0000-00-00, 16:29:44 DDM Port 25 optic module RX power recovered from the low warning threshold
411 0000-00-00, 16:29:44 DDM Port 25 optic module RX power recovered from the low alarm threshold
410 0000-00-00, 16:29:42 DDM Port 25 optic module RX power exceeded the low warning threshold
409 0000-00-00, 16:29:42 DDM Port 25 optic module RX power exceeded the low alarm threshold
If the SFP module supports DDM (Digital Diagnostics Monitoring), then in the switch terminal and via SNMP you can see the level of the optical signal, laser temperature, and other data.
Logs report that the level of the optical signal is very low, but the worker measured it by connecting the cable to the tester and he was normal.
The problem was probably with SFP, so the module was replaced, I looked at the DDM configuration for the Uplink port and, just in case, disabled DDM for this port, since we did not need it:
show ddm ports 1:25 status
show ddm ports 1:25 configuration
config ddm ports 25 state disable
config ddm ports 25 shutdown none
Here are a few more examples of DDM configuration:
config ddm trap disable
config ddm log enable
config ddm ports 25-28 state enable shutdown none
config ddm ports 25-28 state enable shutdown alarm
config ddm ports 25-28 state enable shutdown warning
See also my article:
BDCOM OLT DDM SNMP OID