Cisco Gigabit Ethernet Switch Module for HP p-Class BladeSystem Software Configuration Guide

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Cisco Gigabit Ethernet Switch Module for HP p-Class BladeSystem Software Configuration Guide
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Chapter 9 Configuring VLANs
Configuring Normal-Range VLANs
the network, this could create a loop in the new VLAN that would not be broken, particularly if there
are several adjacent switches that all have run out of spanning-tree instances. You can prevent this
possibility by setting allowed lists on the trunk ports of switches that have used up their allocation
of spanning-tree instances.
If the number of VLANs on the switch exceeds the number of supported spanning-tree instances,
we recommend that you configure the IEEE 802.1s Multiple STP (MSTP) on your switch to map
multiple VLANs to a single spanning-tree instance. For more information about MSTP, see
Chapter 13, “Configuring MSTP.”
VLAN Configuration Mode Options
You can configure normal-range VLANs (with VLAN IDs 1 to 1005) by using these two configuration
modes:
• VLAN Configuration in config-vlan Mode, page 9-6
You access config-vlan mode by entering the vlan vlan-id global configuration command.
• VLAN Configuration in VLAN Database Configuration Mode, page 9-6
You access VLAN database configuration mode by entering the vlan database privileged EXEC
command.
VLAN Configuration in config-vlan Mode
To access config-vlan mode, enter the vlan global configuration command with a VLAN ID. Enter a new
VLAN ID to create a VLAN, or enter an existing VLAN ID to modify that VLAN. You can use the
default VLAN configuration (Table 9-2) or enter multiple commands to configure the VLAN. For more
information about commands available in this mode, see the vlan global configuration command
description in the command reference for this release. When you have finished the configuration, you
must exit config-vlan mode for the configuration to take effect. To display the VLAN configuration,
enter the show vlan privileged EXEC command.
You must use this config-vlan mode when creating extended-range VLANs (VLAN IDs greater than
1005). See the “Configuring Extended-Range VLANs” section on page 9-11.
VLAN Configuration in VLAN Database Configuration Mode
To access VLAN database configuration mode, enter the vlan database privileged EXEC command.
Then enter the vlan command with a new VLAN ID to create a VLAN, or enter an existing VLAN ID
to modify the VLAN. You can use the default VLAN configuration (Table 9-2) or enter multiple
commands to configure the VLAN. For more information about keywords available in this mode, see
the vlan VLAN database configuration command description in the command reference for this release.
When you have finished the configuration, you must enter apply or exit for the configuration to take
effect. When you enter the exit command, it applies all commands and updates the VLAN database. VTP
messages are sent to other switches in the VTP domain, and the privileged EXEC mode prompt appears.