Hello everyone,
Today I will share with you how to prevent packet loss caused by a Single-Fiber fault on an LACP member port in Non-Auto negotiation mode.
Port1 and Port2 between SwitchA and SwitchB are member ports of an LACP link aggregation group and work in non-auto negotiation mode. A fiber between Port1 on SwitchA and Port1 on SwitchB is broken, for example, the fiber between the Tx end of Port1 on SwitchA and the Rx end of Port1 on SwitchB is broken. Port1 on SwitchA is in Up state and Port1 on SwitchB is in Down state, so Port1 on SwitchA is in LACP selected state and Port1 on SwitchB is in LACP unselected state. As a result, packets transmitted from SwitchA to SwitchB are lost on Port1 on SwitchB.

Configure Port1 on SwitchA and Port1 on SwitchB to work in auto-negotiation mode.
Associate EFM OAM with Port1 on SwitchA and Port1 on SwitchB. Run the efm trigger if-down command in the interface view. When the status of Port1 on SwitchA is Down, Port1 on SwitchB is in EFM Down state.
That is all I want to share with you! Thank you!