VLANs

Creating Static VLANs

Static VLANs occur when a switch port is manually assigned by the network administrator to belong to a VLAN. Each port is associated with a specific VLAN. By default, all ports are originally assigned to VLAN 1.

Using VLAN Configuration Mode


NOTE: This method is the only way to configure extended-range VLANs (VLAN IDs from 100 to 4094).

NOTE: Regardless of the method used to create VLANs, the VTP revision number is increased by 1 each time a VLAN is created or changed.


Assigning Ports to VLANs


NOTE: When the switchport mode access command is used, the port operates as a nontrunking, single VLAN interface that transmits and receives nonencapsulated frames.

An access port can belong to only one VLAN.


Using the range Command


Verifying VLAN Information


Saving VLAN Configurations

The configurations of VLANs 1 through 1005 are always saved in the VLAN database. As long as the apply or the exit command is executed in VLAN database mode, changes are saved. If you are using VLAN configuration mode, the exit command saves the changes to the VLAN database, too.

If the VLAN database configuration is used at startup, and the startup configuration file contains extended-range VLAN configuration, this information is lost when the system boots.

If you are using VTP transparent mode, the configurations are also saved in the running
configuration and can be saved to the startup configuration using the copy running-config startup-config command.

If the VTP mode is transparent in the startup configuration, and the VLAN database and the
VTP domain name from the VLAN database matches that in the startup configuration file, the VLAN database is ignored (cleared), and the VTP and VLAN configurations in the startup configuration file are used. The VLAN database revision number remains unchanged in the VLAN database.


Erasing VLAN Configurations


NOTE: When you delete a VLAN from a switch that is in VTP server mode, the VLAN is removed from the VLAN database for all switches in the VTP domain. When you delete a VLAN from a switch that is in VTP transparent mode, the VLAN is deleted only on that specific switch.

NOTE: You cannot delete the default VLANs for the different media types: Ethernet VLAN 1 and FDDI or Token Ring VLANs 1002 to 1005.

CAUTION: When you delete a VLAN, any ports assigned to that VLAN become inactive. They remain associated with the VLAN (and thus inactive) until you assign them to a new VLAN. Therefore, it is recommended that you reassign ports to a new VLAN or the default VLAN before you delete a VLAN from the VLAN database.