Specifications

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Cisco MWR 2941 Mobile Wireless Edge Router Release 3.5 Software Configuration Guide, Cisco IOS Release 15.1(3)MR
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Chapter 8 Configuring IEEE 802.1Q Tunneling and Layer 2 Protocol Tunneling
Configuring 802.1Q Tunneling
802.1Q Tunneling and Other Features
Although 802.1Q tunneling works well for Layer 2 packet switching, there are incompatibilities between
some Layer 2 features and Layer 3 switching.
Routing on VLANs with 802.1Q Tunnel Ports
IP routing is not supported on a VLAN that includes 802.1Q tunnel ports. Packets received from a tunnel
port are forwarded based only on Layer 2 information. The Cisco MWR 2941 does not support routing
on switch virtual interfaces (SVIs).
Configuring an 802.1Q Tunneling Port
Beginning in privileged EXEC mode, follow these steps to configure a port as an 802.1Q tunnel port:
Use the no switchport mode dot1q-tunnel interface configuration command to return the port to the
default state of access. 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 2 is VLAN 22.
Router(config)# interface gigabitethernet0/2
Router(config-if)# switchport access vlan 22
% Access VLAN does not exist. Creating vlan 22
Router(config-if)# switchport mode dot1q-tunnel
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
interface interface-id Enter interface configuration mode for the interface to be configured as a
tunnel port. This should be the edge port in the service-provider network
that connects to the customer switch.
Step 3
no shutdown Enable the port, if necessary. NNIs are enabled by default.
Step 4
switchport access vlan vlan-id Specify the default VLAN, which is used if the interface stops trunking.
This VLAN ID is specific to the particular customer.
Step 5
switchport mode dot1q-tunnel Set the interface as an 802.1Q tunnel port.
Step 6
exit Return to global configuration mode.
Step 7
vlan dot1q tag native (Optional) Set the router to enable tagging of native VLAN packets on all
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.
Step 8
end Return to privileged EXEC mode.
Step 9
show running-config
show dot1q-tunnel
Display the ports configured for 802.1Q tunneling.
Display the ports that are in tunnel mode.
Step 10
show vlan dot1q tag native Display 802.1Q native VLAN tagging status.
Step 11
copy running-config startup-config (Optional) Save your entries in the configuration file.