Specifications

encapsulation dot1q
MP-65
Cisco IOS Multiprotocol Label Switching Command Reference
January 2010
Command History
Usage Guidelines Interface Range Configuration Mode
IEEE 802.1Q encapsulation is configurable on Fast Ethernet interfaces. IEEE 802.1Q is a standard
protocol for interconnecting multiple switches and routers and for defining VLAN topologies.
Use the enc
apsulation dot1q command in interface range configuration mode to apply a VLAN ID to
each subinterface within the range specified by the interface range command. The VLAN ID specified
by the vlan-id argument is applied to the first subinterface in the range. Each subsequent interface is
assigned a VLAN ID, which is the specified vlan-id plus the subinterface number minus the first
subinterface number (VLAN ID + subinterface number – first subinterface number).
Note The Cisco 10000 series router does not support the interface range command nor the interface range
configuration mode.
Do not configure encapsulation on the native VLAN of an IEEE 802.1Q trunk without using the native
keyword. (Always use the native keyword when vlan-id is the ID of the IEEE 802.1Q native VLAN.)
Subinterface Configuration Mode
Use the second-dot1q keyword to configure the IEEE 802.1Q-in-Q VLAN Tag Termination feature.
802.1Q in 802.1Q (Q-in-Q) VLAN tag termination adds another layer of 802.1Q tag (called “metro tag”
or “PE-VLAN”) to the 802.1Q tagged packets that enter the network. Double tagging expands the VLAN
space, allowing service providers to offer certain services such as Internet access on specific VLANs for
some customers and other types of services on other VLANs for other customers.
After a subinterface is defined, use the e
ncapsulation dot1q command to add outer and inner VLAN ID
tags to allow one VLAN to support multiple VLANs. You can assign a specific inner VLAN ID to the
subinterface; that subinterface is unambiguous. Or you can assign a range or ranges of inner VLAN IDs
to the subinterface; that subinterface is ambiguous.
Release Modification
12.0(1)T This command was introduced.
12.1(3)T The na
tive keyword was added.
12.2(2)DD Configuration of this command in interface range mode was introduced.
12.2(4)B This command was integrated into Cisco IOS Release 12.2(4)B.
12.2(8)T This command was integrated into Cisco IOS Release 12.2(8)T.
12.3(7)T The se
cond-dot1q keyword was added to support the IEEE 802.1Q-in-Q
VLAN Tag Termination feature.
12.3(7)XI1 This command was integrated into Cisco IOS Release 12.3(7)XI and
i
mplemented on the Cisco 10000 series routers.
12.2(28)SB This command was integrated into Cisco IOS Release 12.2(28)SB.
12.2(31)SB2 This command was integrated into Cisco IOS Release 12.2(31)SB2.
12.2SX This command is supported in the Cisco IOS Release 12.2SX train. Support
i
n a specific 12.2SX release of this train depends on your feature set,
platform, and platform hardware.
Cisco IOS XE Release
2.
2
This command was integrated into Cisco IOS XE Release 2.2.