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Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
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Chapter 7 Configuring LAN Ports for Layer 2 Switching
Configuring LAN Interfaces for Layer 2 Switching
To configure the Layer 2 switching port as an ISL or 802.1Q trunk, perform this task:
Note Complete the steps in the “Completing Trunk Configuration” section on page 7-13 after performing the
tasks in this section.
Configuring the Layer 2 Trunk to Use DTP
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.
To configure the Layer 2 trunk to use DTP, perform this task:
When configuring the Layer 2 trunk to use DTP, note the following syntax information:
Required only if the interface is a Layer 2 access port or to specify the trunking mode.
See Table 7-2 on page 7-4 for information about trunking modes.
Note Complete the steps in the “Completing Trunk Configuration” section on page 7-13 after performing the
tasks in this section.
Configuring the Layer 2 Trunk Not to Use DTP
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
Router(config-if)# switchport trunk encapsulation
{isl | dot1q | negotiate}
(Optional) Configures the encapsulation, which configures
the Layer 2 switching port as either an ISL or 802.1Q trunk.
Note To support the switchport mode trunk command,
you must configure the encapsulation.
Router(config-if)# no switchport trunk encapsulation Reverts to the default trunk encapsulation mode (negotiate).
Command Purpose
Router(config-if)# switchport mode dynamic {auto |
desirable}
(Optional) Configures the trunk to use DTP.
Router(config-if)# no switchport mode Reverts to the default trunk trunking mode (switchport mode
dynamic desirable).