User's Manual

Key Concepts 101
Figure 23 Clouds – Unknown Topology
The switch port cannot be physically connected to two end stations, and
as such 3Com Network Director inserts the cloud to indicate that there is
something missing. In this case the cloud is where the unmanaged hub
should be.
A similar situation can also occur when insufficient topology information
has been obtained from one or more switches, possibly because 3Com
Network Director lost communication with that switch during the
topology process. If the problem device were an edge switch that is
actually connected to many end stations, 3Com Network Director would
show this as below: