Configuring Layer 2 Learning and Forwarding Properties for a Set of Bridge Domains with a Layer 2 Trunk Port

Layer 2 learning is enabled by default. A set of bridge domains, configured to function as a switch with a Layer 2 trunk port, learns unicast media access control (MAC) addresses to avoid flooding packets to the trunk port.

Note: Traffic is not flooded back onto the interface on which it was received. However, because this “split horizon” occurs at a late stage, the packet statistics displayed by commands such as show interfaces queue will include flood traffic.

You can optionally disable Layer 2 learning for the entire set of bridge domains as well as modify the following Layer 2 learning and forwarding properties:

• Limit the number of MAC addresses learned from the Layer 2 trunk port associated with the set of bridge domains
• Modify the size of the MAC address table for the set of bridge domains
• Enable MAC accounting for the set of bridge domains

For more information about how to configure Layer 2 learning and forwarding properties for a set of bridge domains, see the following sections:

• Disabling MAC Learning for a Set of Bridge Domains
• Limiting the Number of MAC Addresses Learned from a Trunk Port
• Modifying the Size of the MAC Address Table for a Set of Bridge Domains
• Enabling MAC Accounting for a Set of Bridge Domains

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