1. How to Create and Delete VLAN on Cisco Catalyst Switch
VLANs are a mechanism to allow network administrators to create logical broadcast
domains that can span across a single switch or multiple switches, regardless of
physical proximity. This function is useful to reduce the size of broadcast domains or
to allow groups or users to be logically grouped without the need to be physically
located in the same place.
One of the typical configuration activities you’ll perform on a Cisco Switch is to
manipulate VLANs.
VLAN stands for Virtual Local Area Network.
In one physical cisco switch, you can create multiple VLANs that connects to different
network.
For example, a VLAN for 10.10.191.0 network, a VLAN for 10.10.192.0 network, and a
VLAN for 10.10.193.0 network. All three of these can be configured in the same
physical switch.
While these commands were tested on a cisco catalyst switch 3750 series, similar
commands (may be with slight variation to the port number format) should work on
all cisco switches.
Create VLAN on Cisco Switch
If you are planning to have only one network in your whole switch (for example,
10.10.192.0).i.e. All the ports in the switch will be connected to the 10.10.192.0
network, then you don’t need to create a VLAN, just use the default VLAN 1.
Every switch comes with the default VLAN 1 as shown below. In this example, all the
ports in this switch (from 1 through 8) are part of the default VLAN 1.
#show vlan
VLAN Name Status Ports

2. ---- -------------------------------- --------- ------------
1 default active Gi1/0/1, Gi1/0/2, Gi1/0/3, Gi1/0/4
Gi1/0/5, Gi1/0/6, Gi1/0/7, Gi1/0/8
In the following example, we are creating 192 VLAN network (for 10.10.192.0
network). While creating a VLAN you also need to specify the range of ports from the
switch that needs to be part of this VLAN network.
In this example, ports 3 through 6 are configured as part of 192 VLAN network.
config t
vlan 192
interface range gigabitEthernet 1/0/3-6
switchport access vlan 192
exit
In the above commands:
config t – Goes into the configuration mode
vlan 192 – Creates VLAN 192
interface range gigabitEthernet 1/0/3-6 – Indicates that the port numbers 3
through 6 are assigned to this VLAN
swithport access vlan 192 – Indicates that the access to the vlan 192 is
enabled
Apart from providing the access to the vlan 192 for the port numbers 3 through 6,
you can also specify the following additional switchport configuration parameters
(for example, nonegotiate and mode access)
config t
interface range gigabitEthernet 1/0/3-6
switchport mode access
switchportnonegotiate
exit
Once you’ve created a VLAN verify it as shown below,
#show vlan
VLAN Name Status Ports
---- -------------------------------- --------- ------------
1 default active Gi1/0/1, Gi1/0/2, Gi1/0/7, Gi1/0/8
192 VLAN0192 active Gi1/0/3, Gi1/0/4, Gi1/0/5, Gi1/0/6
On a side note, it is always recommended that you upgrade ISO image on your cisco
switch to the latest version.
Delete VLAN on Cisco Switch
You might want to delete a VLAN, if you are planning to switch the ports assigned to
VLAN 192 to a different VLAN. Or, you might want to delete a VLAN, just because

3. you’ve created it by mistake.
Let us assume that you want to delete the VLAN 192 (ports 3 through 6) that you just
created.
Deleting a VLAN is as simple as assigning the default VLAN 1 to the ports that are
part of the VLAN you want to delete, and delete the VLAN.
i.e If you want to delete VLAN 192, assign VLAN 1 to the ports 3 through 6, and just
delete the VLAN 192.
First, assign the default VLAN 1 to ports 3 through 6 as shown below.
interface range gigabitEThernet 1/0/3-6
switchport access vlan 1
exit
Next, delete the vlan itself as shown below.
novlan 192
Finally, verify that the VLAN 192 got deleted as shown below.
#show vlan
VLAN Name Status Ports
---- -------------------------------- --------- ------------
1 default active Gi1/0/1, Gi1/0/2, Gi1/0/3, Gi1/0/4
Gi1/0/5, Gi1/0/6, Gi1/0/7, Gi1/0/8
As a final note, if you don’t know what you are doing, do not execute any of the
above commands on production switch, as you might bring down your network. Do
this only on a test system, where you can play around and learn how to manipulate
VLANs on cisco switch.
More Related: Creating Ethernet VLANs on Catalyst Switches from Cisco’s official
website
http://www.cisco.com/en/US/tech/tk389/tk689/technologies_configuration_exampl
e09186a008009478e.shtml