Symptom

The following l2fm errors are seen on the switch that holds the orphan port: 2022 Feb 03 13:49:49.617315: E_DEBUG l2fm [23344]: l2fm_mcec_rmdb_delete(222): Deleting MAC 0000.0800.0600 vlan 100 from RMDB 2022 Feb 03 13:49:49.617289: E_DEBUG l2fm [23344]: l2fm_handle_mac_move_generic_l2_entry(15255): Ignoring entry if_index 0x1a000800, vl 100 mac 0000.0800.0600 state 3 2022 Feb 03 13:49:49.617131: E_DEBUG l2fm [23344]: l2fm_macdb_insert(9307): unexpected! entry 0000.0800.0600 already exists in SW. skip HW install 2022 Feb 03 13:49:49.617095: E_DEBUG l2fm [23344]: l2fm_macdb_insert(8968): temp_str = slot 0 fe 0 mac 0000.0800.0600 vlan 100 flags 0x400107 hints 0 E8 NL lc : if_index 0x1a000800 old_if_index 0 No L2FM errors on the remote switch l2fm l2dbg macdb on the switch that holds the orphan shows every second: Feb 3 13:49:49 2022:150665 0x1a000800 0 REFRESH_DETECT 3 0 0xffff 1 -- Feb 3 13:49:51 2022:87218 0x1a000800 0 REFRESH_DETECT 3 0 0xffff 3 -- Feb 3 13:49:52 2022:148802 0x1a000800 0 REFRESH_DETECT 3 0 0xffff Feb 3 13:49:49 2022:150654 0x1a000800 0 UPDATE 3 0 0x1 1 -- Feb 3 13:49:51 2022:87207 0x1a000800 0 UPDATE 3 0 0x1 3 -- Feb 3 13:49:52 2022:148791 0x1a000800 0 UPDATE 3 0 0x1 l2fm l2dbg macdb on the remote switch shows: Feb 3 12:18:03 2022:230534 0x1a000800 3 INSERT 2 0 0xffff -- Feb 3 12:48:03 2022:203921 0x1a000800 3 DELETE 2 0 0xffff -- Feb 3 12:48:03 2022:203958 0x1a000800 3 MCEC_DEL_RCVD 2 0 0xffff -- Feb 3 12:48:03 2022:238528 0x1a000800 3 INSERT 2 0 0xffff -- Feb 3 13:18:03 2022:205338 0x1a000800 3 DELETE 2 0 0xffff -- Feb 3 13:18:03 2022:205379 0x1a000800 3 MCEC_DEL_RCVD 2 0 0xffff -- Feb 3 13:18:03 2022:236985 0x1a000800 3 INSERT 2 0 0xffff

Conditions

Cloud Scale N9K running 9.3.8 or earlier Configured subnet for the source of the traffic and no ARP for it, however, the behavior has been seen without that condition

Workaround

Add static ARP entry for the source of the traffic

Further Problem Description