3Com 3C15500 - Network Director User Manual page 535

VLANs tab for devices for which there is no VLAN information
available
If 3Com Network Director has been unable to read any VLAN information
from a device and has been unable to infer any VLAN information about
a device, then the following message is displayed in the VLANs tab on the
Properties dialog box:
Figure 279 VLANs Tab
This may occur if:
The device is a traditional router and does not use VLANs. 3Com
Network Director will not attempt to infer any VLAN membership of
such a device.
There are in fact no VLANs explicitly configured on the network at all.
The only VLANs on the network are configured on non-3Com
switches. 3Com Network Director does not read VLAN information
from non-3Com switches.
Components 531