Delta AS Series Operation Manual page 216

A S S e r i e s O p e r a t i o n M a n u a l
Star Topology
Ring Topology
A DLR function is required to create a ring topology. Refer to Section 9.9.2 for AS series that support DLR.
When a switch is needed for the particular topology, the switch should support the DLR function. If not, the connection
might fail.
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