Configuring The Switch To Tag Native Vlan Traffic; Understanding How Layer 2 Protocol Tunneling Works - Cisco 6500 Series Software Configuration Manual

Chapter 14 Configuring IEEE 802.1Q Tunneling and Layer 2 Protocol Tunneling
Command
Step 4
Router(config-if)# end
Step 5
Router# show dot1q-tunnel [{interface type
interface-number}]
1. type = ethernet, fastethernet, gigabitethernet, or tengigabitethernet
This example shows how to configure tunneling on port 4/1 and verify the configuration:
Router# configure terminal
Router(config)# interface fastethernet 4/1
Router(config-if)# switchport mode dot1qtunnel
Router(config-if)# end
Router# show dot1q-tunnel interface

Configuring the Switch to Tag Native VLAN Traffic

The vlan dot1q tag native command is a global command that configures the switch to tag native VLAN
traffic, and admit only 802.1Q tagged frames on 802.1Q trunks, dropping any untagged traffic, including
untagged traffic in the native VLAN.
To configure the switch to tag traffic in the native VLAN, perform this task:
Command
Step 1
Router(config)# vlan dot1q tag native
Router(config)# no vlan dot1q tag native
Step 2
Router(config)# end
Step 3
Router# show vlan dot1q tag native
This example shows how to configure the switch to tag native VLAN traffic and verify the configuration:
Router# configure terminal
Router(config)# vlan dot1q tag native
Router(config)# end
Router# show vlan dot1q tag native

Understanding How Layer 2 Protocol Tunneling Works

Layer 2 protocol tunneling allows Layer 2 protocol data units (PDUs) (CDP, STP, and VTP) to be
tunneled through a network. This section uses the following terminology:
•
•
•
Without Layer 2 protocol tunneling, tunnel ports drop STP and VTP packets and process CDP packets. This
handling of the PDUs creates different spanning tree domains (different spanning tree roots) for the
customer switches. For example, STP for a VLAN on switch 1 (see
78-14099-04
Edge switch—The switch connected to the customer switch and placed on the boundary of the
service provider network (see
Layer 2 protocol tunnel port—A port on the edge switch on which a specific tunneled protocol can
be encapsulated or deencapsulated. The Layer 2 protocol tunnel port is configured through CLI
commands.
Tunneled PDU—A CDP, STP, or VTP PDU.
Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
Understanding How Layer 2 Protocol Tunneling Works
Purpose
Exits configuration mode.
Verifies the configuration.
Purpose
Configures the switch to tag native VLAN traffic.
Clears the configuration.
Exits configuration mode.
Verifies the configuration.
Figure 14-3).
Figure 14-3) builds a spanning tree
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