Dell PowerConnect 8024 User Manual page 344

Figure 7-51. Double VLAN Global Configuration
The Double VLAN Global Configuration page contains the following fields:
• EtherType — The two-byte hex Ethertype to be used as the first 16 bits of the Double VLAN tag:
802.1Q — Commonly used tag representing 0x8100. This value is supported by several network
–
equipment manufacturers. If a double-tagged frame with the first Ethertype value set to 802.1Q is
forwarded to hardware which does not support Double VLAN (or the corresponding configuration
is not set), it will be misinterpreted as a regular, single-tagged frame.
– vMAN — Commonly used tag representing 0x88A8, defined for the Virtual Metropolitan Area
Network. This value is often used to indicate double-tagged frames. If a double-tagged frame with
an Ethertype value set to vMAN is forwarded to hardware without Double VLAN support (or when
Double VLAN is not configured), it will be dropped due to unknown Ethertype. This outcome
may be more efficient, and cause less harm than when the 802.1Q Ethertype value is used for
double-tagged frames. When presented with a double-tagged frame with an 802.1Q Ethertype
value, the switch that does not support double-tagging may attempt to process the double-tagged
frame with the incorrect assumption that frame contains only a single VLAN tag.
Custom — Use this to specify that double-tagged frames will use a custom Ethertype. A custom
–
Ethertype may be used to make the switch interoperable with specific or non-standard equipment
that does not support 802.1 or vMAN values of Ethertype in double-tagged frames. For more
information, refer to the list of registered Ethertype values for common protocols.
• Custom Type — If Custom is selected in the Ethertype field, enter a custom Ethertype value in any
range from 0 to 65535.
Use the Double VLAN Interface Configuration page to enable or disable Double VLAN mode on a
physical port or LAG.
To access the Double VLAN Interface Configuration page, click Switching → VLAN → Double VLAN
Interface Configuration from the navigation tree.
344
Configuring Switching Information