D-Link DGS-3130 Series Hardware Installation Manual page 48

DGS-3130 Series Layer 3 Stackable Managed Switch Hardware Installation Guide
Figure 4-10 4-port Duplex Ring stacking topology (SFP+ ports)
NOTE: When 4-port duplex ring with 10GBase-T and SFP+ port topology is used and odd number
switches are in one stack, one of the switch in stack should be set as 4-port-SFP+ mode.
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