11-11
Power Over Ethernet (PoE) Operation
General PoE Operation
higher-priority ports. This operation occurs regardless of the order in which
PDs connect to the module’s PoE-enabled ports.
How Is Power Allocation Prioritized?
There are two ways that PoE power is prioritized:
■
Using a
priority class
method, a power priority of
Low
(the default),
High
, or
Critical
is assigned to each enabled PoE port.
■
Using a
port-number priority
method, a lower-numbered port has
priority over a higher-numbered port within the same configured
priority class, for example, port A1 has priority over port A5 if both
are configured with
High
priority.
Suppose, for example, that you configure the PoE priority for a module in slot
C as shown in table 11-2.
Table 11-2. Example of PoE Priority Operation on a PoE Module
Port
Priority
Setting
Configuration Command
1
and Resulting Operation
with PDs connected to Ports C3 Through C24
C3 - C17
Critical
In this example, the following CLI command sets ports C3-C17 to
Critical
:
ProCurve(config)# interface c3-c17 power-over-ethernet
critical
The
Critical
priority class always receives power. If there is not enough power to provision
PDs on all of the ports configured for this class, then no power goes to ports configured for
High
and
Low
priority. If there is enough power to provision PDs on only some of the critical-
priority ports, then power is allocated to these ports in ascending order, beginning with the
lowest-numbered port in the class, which, in this case, is port 3.
C18 - C21
High
In this example, the following CLI command sets ports C19-C22 to
High
:
ProCurve(config)# interface c19-c22 power-over-ethernet high
The
High
priority class receives power only if all PDs on ports with a
Critical
priority setting
are receiving power. If there is not enough power to provision PDs on all ports with a high
priority, then no power goes to ports with a low priority. If there is enough power to provision
PDs on only some of the high-priority ports, then power is allocated to these ports in
ascending order, beginning, in this example, with port 18, until all available power is in use.
3500-5400-6200-8200-MCG-Jan08-K_13_01.book Page 11 Monday, January 28, 2008 10:04 AM