Chapter 6 Configuring the System
Managing the MAC Address Tables
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Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide
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Managing the MAC Address Tables
You can manage the MAC address tables that the switch uses to forward traffic
between ports. All MAC addresses in the address tables are associated with one
or more ports. These MAC tables include the following types of addresses:
•
Dynamic address: a source MAC address that the switch learns and then
drops when it is not in use.
•
Secure address: a manually entered unicast address that is usually associated
with a secured port. Secure addresses do not age.
•
Static address: a manually entered unicast or multicast address that does not
age and that is not lost when the switch resets.
The address tables list the destination MAC address and the VLAN ID, module,
and port number associated with the address.
Figure 6-11
shows an example list
of addresses as they would appear in the dynamic, secure, or static address table.
Figure 6-11 Contents of the Address Table
MAC Addresses and VLANs
All addresses are associated with a VLAN. An address can exist in more than one
VLAN and have different destinations in each. Multicast addresses, for example,
could be forwarded to port 1 in VLAN 1 and ports 9, 10, and 11 in VLAN 5.
Each VLAN maintains its own logical address table. A known address in one
VLAN is unknown in another until it is learned or statically associated with a port
in the other VLAN. An address can be secure in one VLAN and dynamic in
another. Addresses that are statically entered in one VLAN must be static
addresses in all other VLANs.