Installation guide

4
Step 3: Determine the required level
of redundant power
See Table 2 for definitions of the various levels
of redundancy.
No redundancy: Skip to Step 4.
System power redundancy: System power is the
power needed to run the switching and routing
functionality in the switch—essentially everything
except PoE. One power supply is sufficient for full
system power for HP ProCurve Switch 5406zl/8206zl
systems; two power supplies are required for
HP ProCurve Switch 8212zl/5412zl systems. Full
system power redundancy is achieved with two power
supplies for the 5406zl/8206zl systems and four
power supplies for the 8212zl/5412zl systems.
Since there are only two power supply slots
in 8206zl/5406zl chassis, system power N+1
redundancy and full redundancy are equivalent.
8212zl/5412zl systems can have system power
N+1 with three supplies and full redundancy with
four supplies.
PoE power redundancy: PoE wattage is the power
necessary to power the external PDs connected to the
switch. PoE power is independent from system power
and is not used in powering the normal functions of
the switch.
Determine the level of PoE power redundancy you
desire. Table 2 has definitions for the different types of
redundant power.
With software version K13.01 or later, the switch can
be configured to automatically hold PoE power in
reserve based on the desired level of redundancy.
With prior software versions, the switch does not
automatically hold any PoE power in reserve for
redundancy. To ensure PoE redundancy with prior
software versions, plan for the amount of power to be
held in reserve, and keep the wattage needed for the
level of redundancy desired in reserve by controlling
the number of PDs on the switch.
For No redundancy: On failure of one power
supply, PDs using PoE power equal to the PoE power
available from the largest supply installed will have
their PoE power turned off as the power supply losing
power goes down. If after several seconds the switch
determines that there is excess PoE power available
with the remaining supply or supplies, the number of
ports that can be turned back on—using the excess
power available—will have their power restored.
For N+1 redundancy: For software version K13.xx
or later, configure the switch to enforce N+1
redundancy. For prior software versions, hold in
reserve the amount of PoE power available in the
highest-powered power supply.
For Full redundancy: For software version K13.xx or
later, configure the switch to enforce full redundancy.
For prior software versions, hold half the amount of
PoE power available in reserve if all power supplies
in the switch provide the same level of PoE power.
Determine full redundancy reserve power when
unlike power supplies are installed by separating the
installed power supplies into two columns so the total
power in each column is as close in value as possible.
Hold in reserve the amount of power from the column
with the larger added power.
Table 2. Redundant power definitions
No redundancy No power is held in reserve. For system power, if a power supply fails, some or all parts of the switch become
inoperative. For PoE power, all power supplied by the available supplies can be used to power PDs. If a power supply
fails, the amount of PoE power supplied by the failed supply is no longer available. The switch will turn off the number
of PDs starting with the lowest PoE priority PD up to the wattage lost with the failed supply.
N+1 redundancy For system power, one supply can fail and the entire switch remains functional. For PoE power, one power supply can
fail without loss of power to any currently powered device. Under N+1, the switch will hold in reserve (not use) the
amount of PoE power equal to the largest PoE supply. If a power supply fails, the reserve power is used to continue to
power all PDs without interruption. N+1 redundancy may not protect against a failed external power main.
Full redundancy For system power, one-half of the power supplies can fail and the entire switch remains functional. For PoE power,
one-half of the power supplies can fail without power interruption to any connected nodes. The switch will hold at
least one-half of the PoE power available from all supplies in reserve to be used in case of power supply failures. Full
redundancy would be used if protection from a failed external power main is desired.