Rockwell Collins Inc. 8222210 Manuel D’Utilisation

Page de 134
D r a f t   1 A   -   C I S C O   C O N F I D E N T I A L
6-7
Cisco Aironet 1240AG Series Access Point Hardware Installation Guide
OL-7293-01
Chapter 6      Troubleshooting
Low Power Condition
Intelligent Power Management
The access point requires 12.95 W of power for full power operation with both radios, but only needs 
6.3 W of power when operating in low power mode with both radios disabled. To help avoid an 
over-current condition with low power sources and to optimize power usage on Cisco switches, Cisco 
developed Intelligent Power Management, which uses Cisco Discovery Protocol (CDP) to allow 
powered devices (such as your access point) to negotiate with a Cisco switch for sufficient power. 
The access point supports Intelligent Power Management and as a result of the power negotiations, the 
access point will either enter full power mode or remain in low power mode with the radios disabled. 
Note
Independent of the power negotiations, the access point hardware also uses the 802.3af classification 
scheme to indicate the power required from the power source. However, the power source cannot report 
the power available to the access point unless the power source also supports Intelligent Power 
Management.
Some Cisco switches that are capable of supplying sufficient power require a software upgrade to 
support Intelligent Power Management. If the software upgrade is not desired, you can configure the 
access point to operate in pre-standard compatibility mode and the access point automatically enters full 
power mode if these Cisco switches are detected in the received CDP ID field. 
When the access point determines that sufficient power is not available for full power operation, an error 
message is logged and the Status LED turns amber to indicate low power mode (see the 
Tip
If your switch is capable of supplying sufficient power for full operation but the access point remains in 
low-power mode, your access point or your switch (or both) might be misconfigured (see 
If your inline power source is not able to supply sufficient power for full operation, you should consider 
these options:
Upgrade to a higher-powered switch 
Use a Cisco Aironet power injector on the switch port
Use the 48-VDC power module to locally power the access point
Inline Power Status Messages
These messages are logged on the console port by the access point to report the power condition:
%CDP_PD-4-POWER_OK: Full Power - AC_ADAPTOR inline power source—This message 
indicates the access point is using the power module and can support full-power operation.
%CDP_PD-4-POWER_OK: Full Power - NEGOTIATED inline power source—This message 
indicates the access point is operating at full power and has successfully negotiated for 12.95 W of 
power from a Cisco switch supporting Cisco Intelligent Power Management.
%CDP_PD-4-POWER_OK: Full Power - HIGH_POWER_CLASSIC inline power source—This 
message indicates the access point is operating at full power because it has been configured for 
pre-standard compatibility mode and has detected a Cisco switch that does not support Intelligent 
Power Management but is able to supply sufficient power to the access point.