DELL N3000 User Manual

Managing the MAC Address Table

This chapter describes the L2 MAC address table the switch uses to forward 

data between ports.
The topics covered in this chapter include:

• MAC Address Table Overview
• Default MAC Address Table Values
• Managing the MAC Address Table (Web)
• Managing the MAC Address Table (CLI)

The MAC address table keeps track of the MAC addresses that are associated 

with each port to allow the switch to forward unicast traffic through the 

appropriate port. This table is sometimes called the bridge table or the 

forwarding database.

The MAC address table can contain two types of addresses:

• Static: The address has been manually configured and does not age out.
• Dynamic: The address has been automatically learned by the switch and 

can age out when it is not in use.

Static addresses are configured by the administrator and added to the table. 

Dynamic addresses are learned by examining information in the Ethernet 

frame. 
When a frame arrives on a port, the switch looks at the frame header to learn 

the source MAC address of the frame, then adds the address, VLAN ID, and 

the ingress port to the MAC address table. The address table is constantly 

updated as new addresses are learned, and unused addresses age out.
A frame that has a destination MAC address that matches an entry in the 

table is forwarded immediately to the associated port(s)/VLAN(s).