Setting The Mac Learning Limit; Mac Learning-Limit Dynamic - Dell C9000 Series Networking Configuration Manual

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Table of Contents

mac learning-limit mac-address-sticky

mac learning-limit station-move

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 TengigabitEthernet 5/84

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.

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:

no-station-move

station-move

An SNMP trap is available for mac learning-limit station-move. No other SNMP traps are

available for MAC Learning Limit, including limit violations.

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 system does 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, any configured 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 configured the violation action.