Dell PowerSwitch S4820T Configuration Guide for the S4820T System 9.100.0 - Page 485

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 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 converted to sticky MACs on that interface. To remove all sticky MAC addresses from the running config file, disable sticky MAC and use the write config command. When you enable sticky mac on an interface, dynamically-learned MAC addresses do not age, even if you enabled mac-learninglimit dynamic. If you configured mac-learning-limit and mac-learning-limit dynamic and you disabled sticky MAC, any dynamically-learned MAC addresses ages. Layer 2 485