Rockwell Automation 1756-RMxx ControlLogix Enhanced Redundancy System User Manual - Manual (Page 89)

Rockwell Automation Publication 1756-UM535D-EN-P - November 2012 89
Configure the EtherNet/IP Network Chapter 4
During normal operation, one of the active supervisor node’s network ports is
blocked for DLR protocol frames. However, the active supervisor node
continues to send beacon frames out of both network ports to monitor network
health.
The graphic below shows the use of beacon frames sent from the active ring
supervisor.
Figure 23 - Normal DLR Network Operation
Active Ring
Supervisor
Ring Node 1 Ring Node 2 Ring Node 3 Ring Node 4
Beacon Frame
Blocked Port
Beacon Frame
Control Traffic Control Traffic