IBM System Storage DS5020 Installation, User's, And Maintenance Manual page 105

4. Connect port 1B on the right ESM in EXP520 two to port 1 of drive channel 2
on the DS5020.
5. Connect port 1B on the left ESM in EXP520 three to port 1 of drive channel 1
on the DS5020.
6. Connect port 1B on the right ESM in EXP520 three to port 2 of drive channel 2
on the DS5020.
Figure 49 on page 76 shows the cabling scheme for one DS5020 storage
subsystem and four EXP520 storage expansion enclosures behind both ports of a
dual-ported drive channel.
Chapter 3. Cabling the storage subsystem
75