LevelOne GSW-0890 User Manual page 85

Metro Mode:
The Metro Mode is a quick configuration VLAN environment
method on Port-based VLAN. It will create 6 or 7 Port-based VLAN
groups.
Double-tag:
Double-tag mode belongs to the tag-based mode, however, it would
treat all frames as the untagged ones, which means that tag with
PVID will be added into all packets. Then, these packets will be
forwarded as Tag-based VLAN. So, the incoming packets with tag
will become the double-tag ones.
Fig. 3-28
77