Chapter 15: Managing Mac Address Tables - Cisco SF500-24 Administration Manual

Managing MAC Address Tables
Cisco 500 Series Stackable Managed Switch Administration Guide
This section describe how to add MAC addresses to the system. It covers the
following topics:
• Configuring Static MAC Addresses
• Managing Dynamic MAC Addresses
• Defining Reserved MAC Addresses
Types of 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 MAC address that appears in a frame arriving at the switch 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
switch before that time period expires, the MAC entry is deleted from the table.
When a frame arrives at the switch, the switch searches for a corresponding/
matching 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 switch supports a maximum of 16K static and dynamic MAC addresses.
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