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• Learning Limit Violation Actions
• Setting Station Move Violation Actions
• Recovering from Learning Limit and Station Move Violations
Dell Networking OS Behavior: When configuring the MAC learning limit on a port or VLAN, the
configuration is accepted (becomes part of running-config and show mac learning-limit
interface) before the system verifies that sufficient CAM space exists. If the CAM check fails, a message
is displayed:
%E90MH:5 %ACL_AGENT-2-ACL_AGENT_LIST_ERROR: Unable to apply access-list Mac-
Limit on GigabitEthernet 4/24/1
In this case, the configuration is still present in the running-config and show output. Remove the
configuration before re-applying a MAC learning limit with a lower value. Also, ensure that you can view
the Syslog messages on your session.
NOTE: The CAM-check failure message beginning in Dell Networking OS version 8.3.1.0 is different
from versions 8.2.1.1 and earlier, which read:
% Error: ACL returned error
% Error: Remove existing limit configuration if it was configured before
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 off 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
configure 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 affected.
Dell Networking OS Behavior: If you do not configure the dynamic option, the systems do not detect
station moves in which a MAC address learned off of a MAC-limited port is learned on another port on
same line card. Therefore, Dell Networking OS does not take any configured station-move violation
Layer 2
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