Specifications

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Catalyst 2950 and Catalyst 2955 Switch Command Reference
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Chapter 2 Cisco IOS Commands
vlan (global configuration)
When you save the VLAN and VTP configurations in the startup configuration file and reboot the switch,
the configuration is determined in these ways:
• If both the VLAN database and the configuration file show the VTP mode as transparent and the
VTP domain names match, the VLAN database is ignored. The VTP and VLAN configurations in
the startup configuration file are used. The VLAN database revision number remains unchanged in
the VLAN database.
• If the VTP mode is server, or if the startup VTP mode or domain names do not match the VLAN
database, the VTP mode and the VLAN configuration for the first 1005 VLANs use the VLAN
database information.
• If the image on the switch or the configuration file is earlier than IOS release 12.1(9)EA1, the switch
reboots with information in the VLAN database.
If you try to create an extended-range VLAN when the switch is not in VTP transparent mode, the VLAN
is rejected, and you receive an error message.
If you enter an invalid VLAN ID, you receive an error message and do not enter config-vlan mode.
Entering the vlan command with a VLAN ID enables config-vlan mode. When you enter the VLAN ID
of an existing VLAN, you do not create a new VLAN, but you can modify VLAN parameters for that
VLAN. The specified VLANs are added or modified when you exit the config-vlan mode. Only the
shutdown command (for VLANs 1 to 1005) takes effect immediately.
These configuration commands are available in config-vlan mode. The no form of each command returns
the characteristic to its default state.
Note Although all commands are visible, the only config-vlan command supported on extended-range VLANs
is mtu mtu-size. For extended-range VLANs, all other characteristics must remain at the default state.
• are are-number: defines the maximum number of all-routes explorer (ARE) hops for this VLAN.
This keyword applies only to TrCRF VLANs. Valid values are from 0 to 13. The default is 7. If no
value is entered, 0 is assumed to be the maximum.
• backupcrf: specifies the backup CRF mode. This keyword applies only to TrCRF VLANs.
– enable backup CRF mode for this VLAN.
– disable backup CRF mode for this VLAN (the default).
• bridge {bridge-number| type}: specifies the logical distributed source-routing bridge, the bridge
that interconnects all logical rings having this VLAN as a parent VLAN in FDDI-NET, Token
Ring-NET, and TrBRF VLANs. Valid bridge numbers are from 0 to 15. The default bridge number
is 0 (no source-routing bridge) for FDDI-NET, TrBRF, and Token Ring-NET VLANs. The type
keyword applies only to TrCRF VLANs and is one of these:
– srb (source-route bridging)
– srt (source-route transparent) bridging VLAN
• exit: applies changes, increments the VLAN database revision number (VLANs 1 to 1005 only), and
exits config-vlan mode.