13-16
Catalyst 3750 Switch Software Configuration Guide
OL-8550-02
Chapter 13 Configuring VLANs
Displaying VLANs
Displaying VLANs
Use the show vlan privileged EXEC command to display a list of all VLANs on the switch, including
extended-range VLANs. The display includes VLAN status, ports, and configuration information. To
view normal-range VLANs in the VLAN database (1 to 1005), use the show VLAN database
configuration command (accessed by entering the vlan database privileged EXEC command).
Table 13-3 lists the commands for monitoring VLANs.
For more details about the show command options and explanations of output fields, see the command
reference for this release.
Configuring VLAN Trunks
These sections contain this conceptual information:
• Trunking Overview, page 13-16
• Encapsulation Types, page 13-18
• Default Layer 2 Ethernet Interface VLAN Configuration, page 13-19
• Configuring an Ethernet Interface as a Trunk Port, page 13-19
• Configuring Trunk Ports for Load Sharing, page 13-24
Trunking Overview
A trunk is a point-to-point link between one or more Ethernet switch interfaces and another networking device
such as a router or a switch. Ethernet trunks carry the traffic of multiple VLANs over a single link, and you
can extend the VLANs across an entire network.
Two trunking encapsulations are available on all Ethernet interfaces:
• Inter-Switch Link (ISL)—Cisco-proprietary trunking encapsulation.
• IEEE 802.1Q— industry-standard trunking encapsulation.
Table 13-3 VLAN Monitoring Commands
Command Command Mode Purpose
show VLAN database
configuration
Display status of VLANs in the VLAN database.
show current [vlan-id] VLAN database
configuration
Display status of all or the specified VLAN in the
VLAN database.
show interfaces [vlan
vlan-id]
Privileged EXEC Display characteristics for all interfaces or for
the specified VLAN configured on the switch.
show vlan [id vlan-id] Privileged EXEC Display parameters for all VLANs or the
specified VLAN on the switch.
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