Hirschmann RS20 User Manual page 141

Network Load Control
Workstation 1
Figure 31: Example of flow control
Flow Control with a full duplex link

In the example
Workstation 2 and the device.
Before the send queue of port 2 overflows, the device sends a request to
Workstation 2 to include a small break in the sending transmission.
Note: The devices RS20/30/40, MS20/30, Octopus, MACH 100, RSR
and MACH 1000 support flow control in full duplex mode only.
Flow Control with a half duplex link

In the example
Workstation 2 and the device.
Before the send queue of port 2 overflows, the device sends data back so
that Workstation 2 detects a collision and interrupts the sending process.
UM BasicConfig L2E
Release 8.0 05/2013
Port 1 Port 4
Switch
Port 2 Port 3
Workstation 2
(see figure 31) there is a full duplex link between
(see figure 31) there is a half duplex link between
Workstation 3 Workstation 4
8.5 Flow Control
141