S-series Remote I/O with redundant communication over Fiber optic to main controller

S-series Remote I/O with redundant communication over Fiber optic to main controller:

Can any one tell how this communication works? means whether the Remote I/O scanner directly seats on DeltaV Redundant Ethernet network (Network switch) where all main contoller are residing or it is an extention of Main IO chassis as shown in catalogue? What are the other components required for FO interface i.e. Ethernet to FO converters, etc? whether these scanner do have direct FO port available on module?