User Guide
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Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
78-14099-04
Chapter 7 Configuring LAN Ports for Layer 2 Switching
Configuring LAN Interfaces for Layer 2 Switching
Configuring a Custom IEEE 802.1Q EtherType Field Value
With Release 12.1(20)E and later releases, you can configure a custom EtherType field value on a port
to support network devices that do not use the standard 0x8100 EtherType field value on 802.1Q-tagged
or 802.1p-tagged frames.
To configure a custom value for the EtherType field, perform this task:
When configuring a custom EtherType field value, note the following:
• To use a custom EtherType field value, all network devices in the traffic path across the network
must support the custom EtherType field value.
• You can configure a custom EtherType field value on trunk ports, access ports, and tunnel ports.
• Each port supports only one EtherType field value. A port that is configured with a custom
EtherType field value does not recognize frames that have any other EtherType field value as tagged
frames. For example, a trunk port that is configured with a custom EtherType field value does not
recognize the standard 0x8100 EtherType field value on 802.1Q-tagged frames and cannot put the
frames into the VLAN to which they belong.
Caution A port that is configured with a custom EtherType field value considers frames that have any other
EtherType field value to be untagged frames. A trunk port with a custom EtherType field value places
frames with any other EtherType field value into the native VLAN. An access port or tunnel port with a
custom EtherType field value places frames that are tagged with any other EtherType field value into the
access VLAN. If you misconfigure a custom EtherType field value, frames might be placed into the
wrong VLAN.
• You can configure a custom EtherType field value on these modules:
–
Supervisor engines
–
WS-X6516A-GBIC
–
WS-X6516-GBIC
Note The WS-X6516A-GBIC and WS-X6516-GBIC modules apply a configured custom
EtherType field value to all ports supported by each port ASIC (1 through 8 and
9 through 16).
–
WS-X6516-GE-TX
–
WS-X6748-GE-TX
–
WS-X6724-SFP
–
WS-X6704-10GE
–
WS-X6816-GBIC
Command Purpose
Router(config-if)# switchport dot1q ethertype value
Configures the 802.1Q EtherType field value for the port.
Router(config-if)# no switchport dot1q ethertype
Reverts to the default 802.1Q EtherType field value (0x8100).