PoE/PoE+ Planning and Implementation Guide 2011-09

13-11
Planning and Implementation for the E5400zl/E8200zl Switches
Configuration Examples
In this example the load must be balanced or split between two or three
modules in order to effectively use all 546 watts. The number of devices and
wattage must be split between the modules. This would also help limit the
effects of a single module failure. If one module fails, only the devices on that
module would lose power.
Alternatively, one power supply could be used to supply PoE power at 273
watts and the other power supply could be held in reserve as a secondary
power supply if the primary power supply fails. If both power supplies are
connected to different power sources, one could backup the other in case of
failure. With this option the user must manage the PoE usage in order to
maintain redundancy.
Connecting a fully loaded external power supply can double the available PoE
power. See page 13-14.
Figure 13-4. Example of a 5406zl with one power supply, J8713A
In this example (Figure 13-4) there is one J8713A power supply supplying 900
watts for PoE usage. Compared to the J8712A, one J8713A power supply can
supply more PoE wattage than two J8712As.
This configuration offers 116 ports of which all can be powered at 7.5 watts
each, and offers fiber optic gigabit connectivity.
If low wattage devices (4.0 watts) are connected to the switch, a 24 port
module could be installed in each of the six slots providing 144 ports and all
ports could be powered by a single J8713A power supply.
Back
Power Supply
J8713A
Front
900 watts
for PoE
Source of Power Watts Available # of Ports Powered and Average watts/
Port
Redundant # of Ports Powered and
Average watts/Port
Single Internal
PoE Power
Supply (J8713A)
900 58 @ average 15.4 W each
116 @ average 7.5 W each
144 @ average 4.0 W each
None