Understanding Layer 2 Protocol Tunneling - Cisco 3032 Software Configuration Manual

Chapter 17 Configuring IEEE 802.1Q and Layer 2 Protocol Tunneling
Command
Step 5
exit
Step 6 vlan dot1q tag native
Step 7
end
Step 8
show running-config
show dot1q-tunnel
Step 9 show vlan dot1q tag native
Step 10
copy running-config startup-config
Use the no switchport mode dot1q-tunnel interface configuration command to return the port to the
default state of dynamic desirable. Use the no vlan dot1q tag native global configuration command to
disable tagging of native VLAN packets.
This example shows how to configure an interface as a tunnel port, enable tagging of native VLAN
packets, and verify the configuration. In this configuration, the VLAN ID for the customer connected to
Gigabit Ethernet interface 7 on stack member 1 is VLAN 22.
Switch(config)# interface gigabitethernet1/0/7
Switch(config-if)# switchport access vlan 22
% Access VLAN does not exist. Creating vlan 22
Switch(config-if)# switchport mode dot1q-tunnel
Switch(config-if)# exit
Switch(config)# vlan dot1q tag native
Switch(config)# end
Switch# show dot1q-tunnel interface gigabitethernet1/0/7
Port
-----
Gi1/0/1Port
-----
Switch# show vlan dot1q tag native
dot1q native vlan tagging is enabled

Understanding Layer 2 Protocol Tunneling

Customers at different sites connected across a service-provider network need to use various Layer 2
protocols to scale their topologies to include all remote sites, as well as the local sites. STP must run
properly, and every VLAN should build a proper spanning tree that includes the local site and all remote
sites across the service-provider network. Cisco Discovery Protocol (CDP) must discover neighboring
Cisco devices from local and remote sites. VLAN Trunking Protocol (VTP) must provide consistent
VLAN configuration throughout all sites in the customer network.
When protocol tunneling is enabled, edge switches on the inbound side of the service-provider network
encapsulate Layer 2 protocol packets with a special MAC address and send them across the
service-provider network. Core switches in the network do not process these packets but forward them
OL-12247-04
Purpose
Return to global configuration mode.
(Optional) Set the switch to enable tagging of native VLAN packets on
all IEEE 802.1Q trunk ports. When not set, and a customer VLAN ID is
the same as the native VLAN, the trunk port does not apply a metro tag,
and packets could be sent to the wrong destination.
Return to privileged EXEC mode.
Display the ports configured for IEEE 802.1Q tunneling.
Display the ports that are in tunnel mode.
Display IEEE 802.1Q native VLAN tagging status.
(Optional) Save your entries in the configuration file.
Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
Understanding Layer 2 Protocol Tunneling
17-7