On 02.02.2023 at 00:00 a failure of the fiber optic line to Frankfurt (FRA) was detected. All connections via this line were interrupted for a few seconds until an automatic rerouting via Amsterdam (AMS) took place. Due to BGP sessions with low holdtimers and in part active BFD, the impact was low.
This appears to be an unannounced maintenance by the provider of the fiber optic line. There is no impact currently, the traffic is routed via Amsterdam transparently.