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Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 17 Configuring VLANs, VTP, and VMPS
VLANs
When the switch boots, if the VTP domain name and VTP mode in the startup-config and vlan.dat files
do not match, the switch uses the configuration in the vlan.dat file.
You use the interface configuration command mode to define the port membership mode and add and
remove ports from a VLAN. The results of these commands are written to the
running-config file, and
you can display the contents of the file by entering the show running-config command. Beginning with
Cisco IOS Release 15.2(2)E and Cisco IOS XE Release 3.6E, if the VTP mode is off or transparent,
VLAN configuration is saved to the
startup-config file, even when the configuration is not applied to
the interface.
User-configured VLANs have unique IDs from 1 to 4094. To create a VLAN, enter the vlan command
with an unused ID. To verify whether a particular ID is in use, enter the show vlan id ID command
.
To
modify a VLAN, enter the vlan command for an existing VLAN.
See the “VLAN Default Configuration” section on page 17-4 for the list of default parameters that are
assigned when you create a VLAN. If you do not use the media keyword when specifying the VLAN
type, the VLAN is an Ethernet VLAN.
To create a VLAN, perform this task:
When you create or modify an Ethernet VLAN, note the following:
•
Because Layer 3 ports and some software features require internal VLANs allocated from 1006 and
up, configure extended-range VLANs starting with 4094 and work downward.
•
You can configure extended-range VLANs only in global configuration mode. You cannot configure
extended-range VLANs in VLAN database mode.
•
Layer 3 ports and some software features use extended-range VLANs. If the VLAN you are trying
to create or modify is being used by a Layer 3 port or a software feature, the switch displays a
message and does not modify the VLAN configuration.
•
When you create VLANs with the VLAN configuration command, they are automatically added to
the existing VTP domain; no action is required of the user.
Command Purpose
Step 1
Switch# configure terminal
Enters global configuration mode.
Step 2
Switch(config)# vlan vlan_ID
Switch(config-vlan)#
Adds an Ethernet VLAN.
Note You cannot delete the default VLANs for these media types:
Ethernet VLAN 1 and FDDI or Token Ring VLANs 1002 to
1005.
When you delete a VLAN, any LAN interfaces configured as
access ports assigned to that VLAN become inactive. They
remain associated with the VLAN (and thus inactive) until you
assign them to a new VLAN.
Use the no keyword to delete a VLAN.
When the prompt shows Switch(config-vlan)# ; you are in
vlan-configuration mode. If you want to change any of the parameters
for the newly created VLAN, use this mode.
Step 3
Switch(config-vlan)# end
Returns to enable mode from vlan-configuration mode.
Step 4
Switch#
show vlan
[
id | name
]
vlan_name
Verifies the VLAN configuration.