Hirschmann RS20 Reference Manual page 193

Diagnostics 7.4 Topology Discovery
Figure 53: Topology Discovery
If several devices are connected to one port, for example via a hub, the table
will contain one line for each connected device.
When devices both with and without an active topology discovery function
are connected to a port, the topology table hides the devices without active
topology discovery.
When only devices without active topology recognition are connected to a
port, the table will contain one line for this port to represent all devices. This
line contains the number of connected devices.
You can find the MAC addresses of devices, which the topology table hides
for clarity's sake, in the address table (FDB), (see on page 108 "Filter for
MAC addresses").
RM GUI L2E
193
Release 8.0 05/2013