Chapter 16: Managing Mac Address Tables - Cisco Small Business 200 Series Administration Manual

Managing MAC Address Tables
This section describe how to add MAC addresses to the system. It covers the following topics:
• Static MAC Addresses
• Dynamic MAC Addresses
There are two types of MAC addresses—static and dynamic. Depending on their type, MAC addresses are
either stored in the Static Address table or in the Dynamic Address table, along with VLAN and port
information.
Static addresses are configured by the user, and therefore, they do not expire.
A new source MAC address that appears in a frame arriving at the device is added to the Dynamic Address
table. This MAC address is retained for a configurable period of time. If another frame with the same source
MAC address does not arrive at the device before that time period expires, the MAC entry is aged (deleted)
from the table.
When a frame arrives at the device, the device searches for a corresponding/matching destination MAC
address entry in the static or dynamic table. If a match is found, the frame is marked for egress on a the port
specified in the table. If frames are sent to a MAC address that is not found in the tables, they are
transmitted/broadcasted to all the ports on the relevant VLAN. Such frames are referred to as unknown
Unicast frames.
The device supports a maximum of 8K static and dynamic MAC addresses.
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