LevelOne ProCon GSW-1291 User Manual page 85

Metro Mode:
The Metro Mode is a quick configuration VLAN environment
method on Port-based VLAN. It will create 10 or 11 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. 3-27
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User Manual
Publication date: May, 2005
Revision A1