On July 2nd, a WDM multiplexer located on the backbone link between LCLDG and INTX1 (Brussels region) began to show signs of degradation. Initial symptoms started in the morning with a slight dB loss, followed by a sharper drop around 03:45 CEST. The situation escalated further with a significant degradation observed near 21:00, at which point the affected wavelengths experienced complete failure.
Not all optical channels were equally impacted, but the cumulative degradation led to a full service loss on the affected link. OTDR diagnostics confirmed the source of the issue to be a failing MUX. The faulty component was replaced promptly the same night, restoring full functionality.
No alarms were raised prior to the failure. Monitoring confirms that the link is now fully operational.