IBM System Storage Subsystem DS5020 - Manual (Page 94)

One DS5020 and up to six storage expansion enclosures
If you are cabling one DS5020 storage subsystem and up to six storage expansion
enclosures, Figure 42 shows the correct cabling topology.
1A 1B
DS5020
Port 2, drive channel 1
1A 1B
1A 1B
1A 1B
Port 1, drive channel 1
Port 1, drive channel 2
Port 2, drive channel 2
1A 1B
1B
1A 1B
1A 1B
1A 1B
1B
1A 1B
1B
1A
1A
1A
Figure 42. Cabling for one DS5020 and up to six storage expansion enclosures
64 IBM System Storage DS5020 Storage Subsystem: Installation, User’s, and Maintenance Guide