Hirschmann RS20 Reference Manual page 79

Diagnosis
devices without active topology discovery function
are connected to a port, the topology table hides the devices without
active topology discovery.
If
only devices without active topology discovery 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
MAC addresses of devices that the topology table hides for the sake of
clarity, are located in the address table (FDB),
MAC addresses").
RM Web L2B
Release 5.0 04/09
7.3 Topology Discovery
(see on page 51 „Filters for
79