User's Manual

Key Concepts 509
For further information see “Discovering the Network” on page 91.
VLAN membership inference
First, some definitions:
A VLAN-unaware item is:
■ a device that doesn’t support VLANs
■ a device that supports VLANs but has no VLANs configured
■ a device that supports VLANs, with exactly one VLAN configured and
all ports using untagged traffic for that VLAN i.e. factory-default
switches with all ports on the default VLAN.
A VLAN-aware item is any device that does not conform to one of the
above rules.
If a port is a member of a VLAN then 3Com Network Director will infer
that all VLAN-unaware devices hanging off that port are also members of
the same VLAN. For example, consider the network in Figure 263
below.
Figure 263 VLAN Membership Inference