Reference Guide

794 | Power over Ethernet
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For the configuration in Figure 36-2:
• Power for ports 7/1 and 7/2 is terminated first because it is configured with
inline power auto.
• Power for port 7/2 is terminated before PoE for port 7/1 because port 7/1 has a lower port number.
• Power for port 7/0 is terminated last because it is configured with
inline power static.
When a failed PSU is replaced and there is sufficient power for PoE, power is automatically re-supplied for
previously configured PoE ports, and power is supplied first to ports with the highest priority.
Figure 36-6. Order of PoE Re-Supply
Power Additional PoE Ports on the S-Series
By default, 320 Watts is available for PoE on the S50V and S25V models of the S-Series. You have the
option of enabling more power by connecting the external Dell Networking DC 470W Redundant Power
Supply to the Current Sharing terminal of the S50V and S25V. This power supply is in backup mode by
default, but you can use the
power budget stack-unit command to allow that external power supply to be
used for powering PoE ports. 790W is the maximum that you can allocate to PoE, although the combined
output of the internal AC power supply and the external DC power supply is 940W. That external power
supply is the only power supply that you can use to add power for PoE with the S-Series.
Message 28 appears if you attempt to use the
power budget command when an external power supply is
not connected.
Deploying VOIP
VoIP phones on the market today follow the same basic boot and operations process:
1. Wait for an LLDP from the Ethernet switch.
2. Obtain an IP address from a DHCP server.
3. Send an LLDP-MED frame to the switch.
Message 2 External Power Supply Not Found
% Error: External power supply not found or incompatible external power supply.
0
1
2
Re-supply