Cisco - Disabling learning in vlan X for 120s due to too many mac moves
Created: 2023-10-12 20:56:26 | Last modified: 2023-10-12 21:02:40
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Getting an error message: Disabling learning in vlan X for 120s due to too many mac moves
We were getting an error message on our Nexus gear noting that leaning of VLANs were being disabled for 120 seconds.
2023 Oct 13 05:56:23 switch %L2FM-2-L2FM_MAC_FLAP_DISABLE_LEARN: Disabling learning in vlan 101 for 120s due to too many mac moves
2023 Oct 13 05:58:23 switch %L2FM-2-L2FM_MAC_FLAP_RE_ENABLE_LEARN: Re-enabling learning in vlan 101
2023 Oct 13 06:48:24 switch %L2FM-2-L2FM_MAC_FLAP_DISABLE_LEARN: Disabling learning in vlan 101 for 120s due to too many mac moves
2023 Oct 13 06:50:24 switch %L2FM-2-L2FM_MAC_FLAP_RE_ENABLE_LEARN: Re-enabling learning in vlan 101
2023 Oct 13 06:54:48 switch %L2FM-2-L2FM_MAC_FLAP_DISABLE_LEARN: Disabling learning in vlan 101 for 120s due to too many mac moves
2023 Oct 13 06:56:48 switch %L2FM-2-L2FM_MAC_FLAP_RE_ENABLE_LEARN: Re-enabling learning in vlan 101
This could be due to a network loop. To diagnose the issue, set the logging level of l2fm.
switch# configure terminal
switch(config)# logging level l2fm 5
switch(config)# end
switch#
You should start seeing the output to provide details of where the MAC is excessively moving in the logs.
2023 Oct 14 19:04:23.881 N9K %L2FM-4-L2FM_MAC_MOVE2: Mac 0000.114bd.e0ae in vlan 101 has moved between Po117 to Eth1/7
2023 Oct 14 19:04:23.883 N9K %L2FM-4-L2FM_MAC_MOVE2: Mac 0000.114bd.e0ae in vlan 101 has moved between Po117 to Eth1/7
From these logs you can determine where a potential network loop is happening.
