Users Guide
In this case, the conguration is still present in the running-config and show output. Remove the conguration before re-applying a
MAC learning limit with a lower value. Also, ensure that you can view the Syslog messages on your session.
Setting the MAC Learning Limit
To set a MAC learning limit on an interface, use the following command.
• Specify the number of MAC addresses that the system can learn o a Layer 2 interface.
INTERFACE mode
mac learning-limit address_limit
Three options are available with the mac learning-limit command:
– dynamic
– no-station-move
– station-move
NOTE: An SNMP trap is available for mac learning-limit station-move. No other SNMP traps are available for MAC
Learning Limit, including limit violations.
mac learning-limit Dynamic
The MAC address table is stored on the Layer 2 forwarding information base (FIB) region of the CAM.
The Layer 2 FIB region allocates space for static MAC address entries and dynamic MAC address entries. When you enable MAC learning
limit, entries created on this port are static by default. When you congure the dynamic option, learned MAC addresses are stored in the
dynamic region and are subject to aging. Entries created before this option is set are not aected.
Dell Networking OS Behavior: If you do not congure the dynamic option, the system does not detect station moves in which a MAC
address learned o of a MAC-limited port is learned on another port on same line card. Therefore, any congured violation response to
detected station moves is not performed. When a MAC address is relearned on any other line card (any line card except the one to which
the original MAC-limited port belongs), the station-move is detected and the system takes the congured the violation action.
mac learning-limit mac-address-sticky
Using sticky MAC addresses allows you to associate a specic port with MAC addresses from trusted devices. If you enable sticky MAC,
the specied port retains any dynamically-learned addresses and prevents them from being transferred or learned on other ports. Up to
1000 sticky entries are supported on a port.
If you congure mac-learning-limit and you enabled sticky MAC, all dynamically-learned addresses are converted to sticky MAC
addresses for the selected port. Any new MAC addresses learned on the port are converted to sticky MAC addresses.
To save all sticky MAC addresses into a conguration le that can be used as a startup conguration le, use the write config
command. If the number of existing MAC addresses is fewer than the congured MAC learning limit, additional MAC addresses are
converted to sticky MACs addresse on the port. To remove all sticky MAC addresses from the running conguration le, disable sticky
MAC and enter the write config command.
When you enable sticky MAC on an interface, dynamically-learned MAC addresses do not age, even if you enabled mac-learning-
limit dynamic. If you congured mac-learning-limit and mac-learning-limit dynamic and you disabled sticky MAC,
any dynamically-learned MAC address ages.
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Layer 2