VLAN Window
This window appears when you take either of these actions:
- Choose VLAN > VLAN on the menu bar.
- Click
on the toolbar.
You can also click here to launch it.
The window has these tabs:
- Assign VLANs, for assigning
interfaces to a VLAN and specifying what types of interfaces
they are
- Configure Trunks, for specifying a trunk encapsulation
type, restricting VLAN membership, disabling pruning, and changing the native
VLAN
- Configure VTP, for viewing VTP information and specifying
VTP options
- Configure VLANs, for viewing VLAN
information, modifying VLAN options, and adding VLANs
Begin by selecting a device
from the Host Name list. The device that you select determines the VLAN
information, the VTP information, and the configuration choices you
see in the window.
When you finish adding or modifying options, click OK.
This tab identifies:
- The interfaces on the device (Interface)
- The mode that the interface has been set to (Administrative Mode)
- The mode it is operating in (Operational Mode)
Note: This VLAN attribute applies only to Catalyst 2950 and 3550 switches.
- The VLANs, if any, that it is assigned to (Assigned VLANs)
To change the administrative mode or the VLAN assignments
for one or more interfaces:
- Select one or more interfaces.
To select more than one, hold down the Ctrl key and click
individual interfaces, or hold down the Shift key and select
the first and last interfaces in a range.
- Click Modify
to display the Modify VLAN Assignment window.
- Complete the window.
- Click OK to close the window.
Your changes will appear on the Assign VLANs tab.
The columns on this tab vary according to the selected device. The columns
have these meanings.
Column |
Appears for... |
Meaning |
Interface |
Any selected device |
The trunk ports on the device. |
Administrative Trunking Encapsulation |
Catalyst 2950 and 3550 only |
The mode of trucking encapsulation used. |
Operational Trunking Encapsulation |
Catalyst 2950 and 3550 only |
The trunking mode that each port is operating in. |
Allowed VLAN List |
Any selected device |
The VLANs that are allowed to use the trunk. |
VLAN Pruning Eligibility List |
Any selected device |
The VLANs that are eligible for VTP
pruning. |
Native VLAN |
Any selected device |
The native VLAN for the trunk ports. |
To change the trunking encapsulation mode, allowed VLAN list, pruning eligibility
list, or native VLAN:
- Select one or more interfaces.
To select more than one, hold down
the Ctrl key and click individual interfaces, or hold down
the Shift key and select the first and last interfaces in
a range.
- Click Modify to display the Modify Trunk Configuration window.
- Complete the window.
- Click OK to close the window.
Your changes will appear on the Configure Trunks tab.
The read-only fields display information about VTP and the VLAN configuration
it maintains: the version of VTP in use, the current configuration revision
number, the maximum number of VLANs that you can create on the switch, the number
of VLANs that exist on the switch, and the last time the VLAN configuration
was modified.
To configure VTP:
- From the VTP V2 Mode list, select Enabled
to enable version 2.
By default, Disabled is selected, which means that
version 1 mode is selected.
Each VTP switch automatically detects the capabilities of
all the other VTP devices. All VTP switches in the network
must support version 2 mode; otherwise, you must configure
them to operate with VTP version 1.
Note: If you are using VTP in a Token Ring
environment or configuring a TRBRF or TRCRF VLAN media type,
you must set VTP V2 Mode to Enabled. If you
are configuring a Token Ring or Token Ring-NET VLAN media
type, you must disable VTP V2 mode.
- From the VTP Mode Control list, select a
mode. This table explains the choices.
Mode |
Explanation |
Server |
A switch in VTP server mode is enabled
for VTP and sends advertisements. You can configure
VLANs on it. The switch can recover all the VLAN information
in the current VTP database from nonvolatile storage
after reboot. By default, every switch is a VTP server,
which is the recommended mode of operation. |
Client |
A switch in VTP client mode is enabled
for VTP and can send advertisements, but it does not
have enough nonvolatile storage to store VLAN configurations.
You cannot configure VLANs on it. When a VTP client
starts up, it does not transmit VTP advertisements until
it receives advertisements to initialize its VLAN database. |
Transparent |
A switch in VTP transparent mode is locally
disabled for VTP, but it does not transmit advertisements
or learn from advertisements sent by other devices,
and it cannot affect VLAN configurations on other devices
in the network. The switch receives VTP advertisements
and forwards them on all trunk ports except the one
on which the advertisement was received. |
The default is Server.
If you select Client, you cannot add, modify,
or remove VLAN configurations.
The mode must be Transparent if the selected device is a Catalyst 2950 or 3550
switch on a VLAN whose ID is 1006 to 4094.
- From the VTP Pruning Mode list,
select Enabled.
By default, pruning is disabled. When enabled, global pruning
occurs for the entire management domain. Pruning restricts
flooded traffic to trunk links that the traffic must use to
access ports where the traffic is required.
Note: You can specify the VLANs where pruning is done by
using the VLAN Pruning Eligibility section of the Modify Trunk Configuration
window.
- In the Domain Name field, enter
a name that identifies the administrative domain for the switch.
Note: Do not configure a domain name if all
switches are operating as VTP clients; in this case, configuring
a domain name makes changing the VLAN configuration for the
domain impossible.
By default, no domain name is defined, but VTP is not active
until a name is defined or until it is learned from an advertisement.
Domain names range from 1 to 32 characters and are case sensitive.
Note: After the domain name is configured
or learned, you cannot reset it to a blank or undefined name.
If you are configuring the switch for VMPS, make sure this
domain name matches the one in the VMPS configuration file.
- Optional: In the VTP Password field,
enter a password.
Passwords range from 8 to 64 characters and are case sensitive.
By default, no password is defined.
If you assign a VTP password, it must match the password for the VTP domain
of the switch. This password is required for authentication when VTP advertisements
reach the switch.
Note: Catalyst 2900 XL or 3500 XL switches that boot without
the correct VTP password reject VTP advertisements until this password is
assigned. If you add a switch to a network that uses VTP, the switch learns
the VTP domain name after the domain password is assigned.
This tab displays
information about the VLANs that are associated with the selected device.
If you want to see the device ports in the Front Panel view that belong to
a VLAN:
- Select the VLAN by selecting a row in the table.
- Click Highlight VLAN Port Membership Modes.
The color that outlines the ports in the Front Panel view represents a VLAN
mode. Go to VLAN Modes in the legend to see
what colors represent the VLAN modes.
The information in the table is updated when you take one of these
actions:
- Add a VLAN by clicking Create and using the Create VLAN window.
- Modify a VLAN by selecting a row of information, clicking Modify,
and using the Modify VLAN window.
- Remove a VLAN by selecting a row of information and clicking Remove.