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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
NOTE:
When the system receives SLF packets with about 25000 packets per second and 2500 packets per burst, the system
does not learn all MAC addresses. The system learns all MAC addresses on subsequent reception of packets.
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 system does not detect station moves in which a MAC
address learned from a MAC-limited port is learned on another port on the same system. 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.
mac learning-limit mac-address-sticky
Using sticky MAC addresses allows you to associate a specific port with MAC addresses from trusted devices. If you enable sticky MAC,
the specified port retains any dynamically-learned addresses and prevents them from being transferred or learned on other ports.
If you configure 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 this port is converted to sticky MAC addresses.
To save all sticky MAC addresses into a configuration file that can be used as a startup configuration file, use the write config
command. If the number of existing MAC addresses is fewer than the configured mac learn limit, any additional MAC addresses are
Layer 2
437
- Quick Links:
- Accessing the Command Line
- Cli Modes
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Troubleshooting
