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Catalyst 2960 Switch SoftwareConfiguration Guide
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Chapter12 Configuring VLANs
Configuring Extended-Range VLANs
Extended-Range VLAN Configuration Guidelines
Follow these guidelines when creating extended-range VLANs:
•To add an extended-range VLAN, you must use the vlan vlan-id global configuration command and
access config-vlan mode. You cannot add extended-range VLANs in VLAN database configuration
mode (accessed by entering the vlan database privileged EXEC command).
•VLAN IDs in the extended range are not saved in the VLAN database and are not recognized by
VTP.
•You cannot include extended-range VLANs in the pruning eligible range.
•The switch must be in VTP transparent mode when you create extended-range V LANs. If VTP mode
is server or client, an error message is generated, and the extended-range VLAN is rejected.
•You can set the VTP mode to transparent in global configuration mode or in VLAN database
configuration mode. See the “Disabling VTP (VTP Transparent Mode)” sectio n on page 13-12. You
should save this configuration to the startup configuration so that the switch boots up in VTP
transparent mode. Otherwise, you lose the extended-range VLAN configuration if the switch resets.
•STP is enabled by default on extended-range VLANs, but you can disable it by using the no
spanning-tree vlan vlan-id global configuration command. When the ma ximum number of
spanning-tree instances are on the switch, spanning tree is disabled on any newly created VLANs.
If the number of VLANs on the switch exceeds the maximum number of spanning-tree instances,
we recommend that you configure the IEEE 802.1s Multiple STP (MSTP) on your switch to map
multiple VLANs to a single spanning-tree instance. For more information about MSTP, see
Chapter 16, “Configuring MSTP.”
•Although the switch supports a total of 255 (normal-range and extended-ra nge) VLANs, the number
of configured features affects the use of the switch hardware. If you try to create an extended-range
VLAN and there are not enough hardware resources available, an error message is generated, and
the extended-range VLAN is rejected.
Creating an Extended-Range VLAN
You create an extended-range VLAN in global configuration mode by entering the vlan global
configuration command with a VLAN ID from 1006 to 4094. This command accesses the config-vlan
mode. The extended-range VLAN has the default Ethernet VLAN characteristics (see Table 12-2) and
the MTU size, and RSPAN configuration are the only parameters you can change. See the description of
the vlan global configuration command in the command refer ence for the default settings of all
parameters. If you enter an extended-range VLAN ID when the switch is not in VTP transparent mode,
an error message is generated when you exit from config-vlan mode, and the extended-range VLAN is
not created.
Extended-range VLANs are not saved in the VLAN database; they are saved in the switch running
configuration file. You can save the extended-range VLAN configuration in the switch startup
configuration file by using the copy running-config startup-config privileged EXEC command.
Beginning in privileged EXEC mode, follow these steps to create an extended-range VLAN:
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 vtp mode transparent Configure the switch for VTP transparent mode, disabling VTP.