7-8
Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
78-14099-04
Chapter 7 Configuring LAN Ports for Layer 2 Switching
Configuring LAN Interfaces for Layer 2 Switching
Configuring a Layer 2 Switching Port as a Trunk
These sections describe configuring a Layer 2 switching port as a trunk:
Preparing a Layer 2 Switching Port for Configuration as a Trunk, page 7-8
Configuring the Layer 2 Switching Port as an ISL or 802.1Q Trunk, page 7-8
Configuring the Layer 2 Trunk to Use DTP, page 7-9
Configuring the Layer 2 Trunk Not to Use DTP, page 7-9
Configuring the Default VLAN, page 7-10
Configuring the 802.1Q Native VLAN, page 7-11
Configuring the List of VLANs Allowed on a Trunk, page 7-11
Configuring the List of Prune-Eligible VLANs, page 7-12
Completing Trunk Configuration, page 7-13
Verifying Layer 2 Trunk Configuration, page 7-13
Configuration and Verification Examples, page 7-13

Preparing a Layer 2 Switching Port for Configuration as a Trunk

To prepare a Layer 2 switching port for configuration as a trunk, perform this task:

Configuring the Layer 2 Switching Port as an ISL or 802.1Q Trunk

Note Complete the steps in the “Preparing a Layer 2 Switching Port for Configuration as a Trunk” section on
page 7-8 before performing the tasks in this section.
Command Purpose
Step 1 Router(config)# interface type1 slot/port
1. type = ethernet, fastethernet, gigabitethernet, or tengigabitethernet
Selects the LAN port to configure.
Step 2 Router(config-if)# shutdown (Optional) Shuts down the interface to prevent traffic flow
until configuration is complete.
Step 3 Router(config-if)# switchport (Optional) Configures the LAN port for Layer 2
switching (required only if the LAN port is not already
configured for Layer 2 switching; see the “Configuring a
LAN Port for Layer 2 Switching” section on page 7-7).