Specifications

2-346
Catalyst 2950 and Catalyst 2955 Switch Command Reference
78-15304-01
Chapter 2 Cisco IOS Commands
vlan (global configuration)
Table 2-23 describes the rules for configuring VLANs.
Examples This example shows how to add an Ethernet VLAN with default media characteristics. The default
includes a vlan-name of VLANxxx, where xxxx represents four numeric digits (including leading zeros)
equal to the VLAN ID number. The default media option is ethernet; the state option is active. The
default said-value variable is 100000 plus the VLAN ID; the mtu-size variable is 1500; the stp-type
option is ieee. When you enter the exit config-vlan configuration command, the VLAN is added if it did
not already exist; otherwise, this command does nothing.
This example shows how to create a new VLAN with all default characteristics and enter config-vlan
mode:
Switch(config)# vlan 200
Switch(config-vlan)# exit
Switch(config)#
Table 2-23 VLAN Configuration Rules
Configuration Rule
VTP v2 mode is enabled, and you
are configuring a TrCRF VLAN
media type.
Specify a parent VLAN ID of a TrBRF that already exists in the
database.
Specify a ring number. Do not leave this field blank.
Specify unique ring numbers when TrCRF VLANs have the same
parent VLAN ID. Only one backup concentrator relay function
(CRF) can be enabled.
VTP v2 mode is enabled, and you
are configuring VLANs other than
TrCRF media type.
Do not specify a backup CRF.
VTP v2 mode is enabled, and you
are configuring a TrBRF VLAN
media type.
Specify a bridge number. Do not leave this field blank.
VTP v1 mode is enabled. No VLAN can have an STP type set to auto.
This rule applies to Ethernet, FDDI, FDDI-NET, Token Ring, and
Token Ring-NET VLANs.
Add a VLAN that requires
translational bridging (values are
not set to zero).
The translational bridging VLAN IDs that are used must already
exist in the database.
The translational bridging VLAN IDs that a configuration points
to must also contain a pointer to the original VLAN in one of the
translational bridging parameters (for example, Ethernet points to
FDDI, and FDDI points to Ethernet).
The translational bridging VLAN IDs that a configuration points
to must be different media types than the original VLAN (for
example, Ethernet can point to Token Ring).
If both translational bridging VLAN IDs are configured, these
VLANs must be different media types (for example, Ethernet can
point to FDDI and Token Ring).