Configuration Guidelines For Extended-Range Vlans; Creating An Extended-Range Vlan - Cisco Catalyst 2950 Software Configuration Manual

Chapter 13 Configuring VLANs

Configuration Guidelines for Extended-Range VLANs

Follow these guidelines when creating extended-range VLANs:
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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
the MTU size is the only parameter you can change. Refer to the description of the vlan global
configuration command in the Catalyst 2950 Desktop Switch Command Reference for defaults 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.
Note Before you create an extended-range VLAN, you can verify that the VLAN ID is not used internally by
entering the show vlan internal usage privileged EXEC command. If the VLAN ID is used internally
and you want to free it up, go to
extended-range VLAN.
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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 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 VLANs. 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 configuration
mode. See the "Disabling VTP (VTP Transparent Mode)" section on page
this configuration to the startup configuration so that the switch will boot up in VTP transparent
mode. Otherwise, you will lose extended-range VLAN configuration if the switch resets.
VLANs in the extended range are not supported by VQP. They cannot be configured by VMPS.
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 maximum number of
spanning-tree instances (64) are on the switch, spanning tree is disabled on any newly created
VLANs. If the number of VLANs on the switch exceeds 64, we recommend that you configure the
IEEE 802.1S Multiple STP (MSTP) on your switch to map multiple VLANs to a single STP
instance. For more information about MSTP, see Chapter 11, "Configuring RSTP and MSTP."
the"Displaying VLANs" section on page 13-16
Catalyst 2950 Desktop Switch Software Configuration Guide
Configuring Extended-Range VLANs
14-12. You should save
Table 13-3) and
before creating the
13-15