Cisco Catalyst 3750 - Configuring VLAN Mapping

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Catalyst 3750 MetroSwitch Software Configuration Guide
78-15870-01
Chapter 13 Configuring IEEE 802.1Q and Layer 2 Protocol Tunneling
Configuring VLAN Mapping
Use the no switchport mode dot1q-tunnel interface configuration command to return the port to the
default state of dynamic auto. Use the no vlan dot1q tag native global configuration command to
disable tagging of native VLAN packets.
This example shows how to configure aport 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 Fast
Ethernet port 7 is VLAN 22.
Switch(config)# interface fastethernet1/0/7
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 fastethernet1/0/7
Port
-----
Fa1/0/7
-----
Switch# show vlan dot1q tag native
dot1q native vlan tagging is enabled
Configuring VLAN Mapping
VLAN mapping, or VLAN ID translation, is a feature that you can configure on the enhanced-services
(ES) ports connected to the service-provider network to map the customer VLANs to service-provider
VLANs. VLAN mapping acts as a filter on the ES ports without affecting the internal operation of the
switch or the customer VLANs. A switch might also have a number of reserved VLANs or have a limited
VLAN range. When customers want to use a VLAN number in the reserved range, you can use VLAN
mapping to overlap customer VLANs by encapsulating the customer traffic in 802.1Q tunnels.
With VLAN mapping, the customer VLAN ID in the 802.1Q or ISL tag, or the inner and outer tag in an
802.1Q tunneled frame, are mapped (or translated) just before a packet is transmitted and just after a
packet is received. The service-provider VLANs are not seen by the switch, so all configuration and
statistics are done with the customer side-VLANs.
Note Do not configure VLAN mapping on an interface configured for MPLS or EoMPLS.
Step 5
exit Return to global configuration mode.
Step 6
vlan dot1q tag native (Optional) Set the switch to enable tagging of native VLAN packets on all
802.1Q trunk ports. When not set, if a customer VLAN ID is the same as
the native VLAN, the trunk port does not apply a metro tag, and packets
might be sent to the wrong destination.
Step 7
end Return to privileged EXEC mode.
Step 8
show dot1q-tunnel Display the tunnel ports on the switch.
Step 9
show vlan dot1q tag native Display 802.1Q native VLAN tagging status.
Step 10
copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose