- N+N refers to power source redundancy. For instance, a data center may have two independent power sources available so that if one source fails, the other source (backup) will automatically take over and power the ExtremeSwitching X8 Series (formerly BlackDiamond X Series) chassis.
- To achieve N+N redundancy, the top row of PSUs (Bank A) should be powered from the same facility power source – that is, plugged into power circuits derived from a single power source. The bottom row of PSUs (Bank B) should be powered from the backup power source.
- You must install enough PSUs in each bank to power the entire chassis. If the line voltage is 220 VAC, it is likely that the entire chassis can be powered with four PSUs. If the line voltage is 120 VAC, most configurations can be powered by four PSUs.