Chapter 18
| VLAN Commands
Configuring IEEE 802.1Q Tunneling
– 485 –
dot1q-tunnel tpid This command sets the Tag Protocol Identifier (TPID) value of a tunnel port. Use the
no form to restore the default setting.
Syntax
dot1q-tunnel tpid tpid
no dot1q-tunnel tpid
tpid – Sets the ethertype value for 802.1Q encapsulation. This identifier is
used to select a nonstandard 2-byte ethertype to identify 802.1Q tagged
frames. The standard ethertype value is 0x8100. (Range: 0800-FFFF
hexadecimal)
Default Setting
0x8100
Command Mode
Global Configuration
Command Usage
◆ Use the switchport dot1q-tunnel tpid command to set a custom 802.1Q
ethertype value on the switch. This feature allows the switch to interoperate
with third-party switches that do not use the standard 0x8100 ethertype to
identify 802.1Q-tagged frames. For example, 0x1234 is set as the custom
802.1Q ethertype on a trunk port, incoming frames containing that ethertype
are assigned to the VLAN contained in the tag following the ethertype field, as
they would be with a standard 802.1Q trunk. Frames arriving on the port
containing any other ethertype are looked upon as untagged frames, and
assigned to the native VLAN of that port.
◆ The specified ethertype only applies to ports configured in Uplink mode using
the switchport dot1q-tunnel mode command. If the port is in normal mode,
the TPID is always 8100. If the port is in Access mode, received packets are
processes as untagged packets.
◆ Avoid using well-known ethertypes for the TPID unless you can eliminate all
side effects. For example, setting the TPID to 0800 hexadecimal (which is used
for IPv4) will interfere with management access through the web interface.
Example
Console(config)#dot1q-tunnel tpid 9100
Console(config)#
Related Commands
show interfaces switchport (377)
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