Mac Address Table; Mac Addresses And Vlans - Cisco IE-4000 Software Configuration Manual

Performing Switch Administration
Information About Performing Switch Administration
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System Name and Prompt
You configure the system name on the switch to identify it. By default, the system name and prompt are Switch.
If you have not configured a system prompt, the first 20 characters of the system name are used as the system prompt.
A greater-than symbol [>] is appended. The prompt is updated whenever the system name changes.

MAC Address Table

The MAC address table contains address information that the switch uses to forward traffic between ports. All MAC
addresses in the address table are associated with one or more ports. The address table includes these types of
addresses:

Dynamic address—A source MAC address that the switch learns and then ages when it is not in use.

Static address—A manually entered unicast address that does not age and that is not lost when the switch resets.
The address table lists the destination MAC address, the associated VLAN ID, and port number associated with the
address and the type (static or dynamic).
Address Table
With multiple MAC addresses supported on all ports, you can connect any port on the switch to individual workstations,
repeaters, switches, routers, or other network devices. The switch provides dynamic addressing by learning the source
address of packets it receives on each port and adding the address and its associated port number to the address table.
As stations are added or removed from the network, the switch updates the address table, adding new dynamic
addresses and aging out those that are not in use.
The aging interval is globally configured. However, the switch maintains an address table for each VLAN, and STP can
accelerate the aging interval on a per-VLAN basis.
The switch sends packets between any combination of ports, based on the destination address of the received packet.
Using the MAC address table, the switch forwards the packet only to the port associated with the destination address.
If the destination address is on the port that sent the packet, the packet is filtered and not forwarded. The switch always
uses the store-and-forward method: complete packets are stored and checked for errors before transmission.

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. Unicast addresses, for example, could be forwarded to port 1 in VLAN 1 and ports 9, 10, and 1 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.
When private VLANs are configured, address learning depends on the type of MAC address:

Dynamic MAC addresses learned in one VLAN of a private VLAN are replicated in the associated VLANs. For
example, a MAC address learned in a private-VLAN secondary VLAN is replicated in the primary VLAN.

Static MAC addresses configured in a primary or secondary VLAN are not replicated in the associated VLANs. When
you configure a static MAC address in a private VLAN primary or secondary VLAN, you should also configure the
same static MAC address in all associated VLANs.
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