13-4
Catalyst 2975 Switch Software Configuration Guide
OL-19720-02
Chapter 13 Configuring VLANs
Configuring Normal-Range VLANs
When a port belongs to a VLAN, the switch learns and manages the addresses associated with the port
on a per-VLAN basis. For more information, see the
“Managing the MAC Address Table” section on
Configuring Normal-Range VLANs
Normal-range VLANs are VLANs with VLAN IDs 1 to 1005. If the switch is in VTP server or
VTP transparent mode, you can add, modify or remove configurations for VLANs 2 to 1001 in the
VLAN database. (VLAN IDs 1 and 1002 to 1005 are automatically created and cannot be removed.)
In VTP versions 1 and 2, the switch must be in VTP transparent mode when you create extended-range
VLANs (VLANs with IDs from 1006 to 4094), but these VLANs are not saved in the VLAN database.
VTP version 3 supports extended-range VLANs in VTP server and transparent mode. See the
“Configuring Extended-Range VLANs” section on page 13-10
.
Configurations for VLAN IDs 1 to 1005 are written to the file
vlan.dat
(VLAN database), and you can
display them by entering the
show vlan
privileged EXEC command. The
vlan.dat
file is stored in flash
memory on the stack master. Stack members have a vlan.dat file that is consistent with the stack master.
Caution
You can cause inconsistency in the VLAN database if you attempt to manually delete the
vlan.dat
file.
If you want to modify the VLAN configuration, use the commands described in these sections and in the
command reference for this release. To change the VTP configuration, see
You use the interface configuration mode to define the port membership mode and to add and remove
ports from VLANs. The results of these commands are written to the running-configuration file, and you
can display the file by entering the
show running-config
privileged EXEC command.
You can set these parameters when you create a new normal-range VLAN or modify an existing VLAN
in the VLAN database:
•
VLAN ID
•
VLAN name
•
VLAN type (Ethernet, Fiber Distributed Data Interface [FDDI], FDDI network entity title [NET],
TrBRF, or TrCRF, Token Ring, Token Ring-Net)
•
VLAN state (active or suspended)
•
Maximum transmission unit (MTU) for the VLAN
•
Security Association Identifier (SAID)
•
Bridge identification number for TrBRF VLANs
•
Ring number for FDDI and TrCRF VLANs
•
Parent VLAN number for TrCRF VLANs
•
Spanning Tree Protocol (STP) type for TrCRF VLANs
•
VLAN number to use when translating from one VLAN type to another
Note
This section does not provide configuration details for most of these parameters. For complete
information on the commands and parameters that control VLAN configuration, see the command
reference for this release.