Configuring A Layer 2 Switching Port As A Trunk - Cisco WS-SUP32-GE-3B - Supervisor Engine 32 Software Configuration Manual

Configuring LAN Interfaces for Layer 2 Switching

Configuring a Layer 2 Switching Port as a Trunk

These section describe configuring a Layer 2 switching port as a trunk:
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Configuring the Layer 2 Switching Port as an ISL or 802.1Q Trunk
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To configure the Layer 2 switching port as an ISL or 802.1Q trunk, perform this task:
Command
Router(config-if)# switchport trunk encapsulation
{isl | dot1q | negotiate}
Router(config-if)# no switchport trunk encapsulation
When configuring the Layer 2 switching port as an ISL or 802.1Q trunk, note the following information:
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Catalyst Supervisor Engine 32 PISA Cisco IOS Software Configuration Guide, Release 12.2ZY
8-8
Configuring the Layer 2 Switching Port as an ISL or 802.1Q Trunk, page 8-8
Configuring the Layer 2 Trunk to Use DTP, page 8-9
Configuring the Layer 2 Trunk Not to Use DTP, page 8-9
Configuring the Access VLAN, page 8-10
Configuring the 802.1Q Native VLAN, page 8-10
Configuring the List of VLANs Allowed on a Trunk, page 8-11
Configuring the List of Prune-Eligible VLANs, page 8-11
Completing Trunk Configuration, page 8-12
Verifying Layer 2 Trunk Configuration, page 8-12
Configuration and Verification Examples, page 8-13
Complete the steps in the
before performing the tasks in this section.
When you enter the switchport command with no other keywords
the default mode is switchport mode dynamic desirable and switchport trunk encapsulation
negotiate.
The switchport mode trunk command (see the
section on page 8-9) is not compatible with the switchport trunk encapsulation negotiate
command.
To support the switchport mode trunk command, you must configure the encapsulation as either
ISL or 802.1Q.
The following switching modules do not support ISL encapsulation:
WS-X6502-10GE
–
WS-X6548-GE-TX, WS-X6548V-GE-TX, WS-X6548-GE-45AF
–
– WS-X6148-GE-TX, WS-X6148V-GE-TX, WS-X6148-GE-45AF
"Configuring a LAN Port for Layer 2 Switching" section on page 8-7
Purpose
(Optional) Configures the encapsulation, which configures
the Layer 2 switching port as either an ISL or 802.1Q trunk.
Reverts to the default trunk encapsulation mode (negotiate).
"Configuring the Layer 2 Trunk Not to Use DTP"
Chapter 8 Configuring LAN Ports for Layer 2 Switching
(Step 3 in the previous section),
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