HPE Knowledge Article
Aruba AP225 - AP running with POE restrictions when connected to Cisco
802.3af switch without LLDP
Article Number mmr_sf-EN_US000015028
Environment
Aruba Controller and AP225
Cisco 3850 802.3at switch
Issue
Prior to 6.5.0.4, when an Aruba AP225 is connected to a Cisco 3850 802.3at switch with LACP enable but without LLDP the POE
Operational state for that access point is “POE-AT: No restrictions” and the both ports of the LACP aggregation are UP.
(WLC) #show ap debug system-status ap-name AP225 | begin "Power Status"
Power Status
-----------Operational State POE-AT: No restrictions
----------------- ----------------------Current HW State POE-AT: No restrictions
LLDP Negotiated POE Power 0.0W
(WLC) # show ap port status ap-name AP225
AP "AP225" Port Status (updated every 60 seconds)
-------------------------------------------------------Port MAC Type Forward Mode Admin Oper Speed Duplex 802.3az PoE STP TX-Packets TX-Bytes RX-Packets RX-Bytes
---- --- ---- ------------ ----- ---- ----- ------ ------- --- --- ---------- -------- ---------- -------0 04:bd:88:cc:df:78 GE N/A enabled up 1 Gb/s full disabled N/A N/A 96280731 2384664381 111810385 2242382019
1 04:bd:88:cc:df:79 GE none enabled up 1 Gb/s full disabled N/A N/A 358979 72154395 185118 50330604
After the upgrade of the Aruba controller and Access Point to version 6.5.0.4, when an Aruba AP225 is connected to a Cisco 3850
802.3at switch with LACP enable but without LLDP the POE Operational state for that access point is “POE-AF: One Ethernet port
disabled; USB port disabled; 1x3 chain for 2.4GHz; 3x3 chain for 5GHz” ” and one of the two ports of the LACP aggregation will be
down.
(WLC) #show ap debug system-status ap-name AP225 | begin "Power Status"
Power Status
-----------Operational State POE-AF: One Ethernet port disabled; USB port disabled; 1x3 chain for 2.4GHz; 3x3 chain for 5GHz
----------------- ----------------------------------------------------------------------------------------------Current HW State POE-AF: One Ethernet port disabled; USB port disabled; 1x3 chain for 2.4GHz; 3x3 chain for 5GHz
LLDP Negotiated POE Power 0.0W
(WLC) # show ap port status ap-name AP225
AP "AP225" Port Status (updated every 60 seconds)
-------------------------------------------------------Port MAC Type Forward Mode Admin Oper Speed Duplex 802.3az PoE STP TX-Packets TX-Bytes RX-Packets RX-Bytes
---- --- ---- ------------ ----- ---- ----- ------ ------- --- --- ---------- -------- ---------- -------0 04:bd:88:cc:df:78 GE N/A enabled up 1 Gb/s full disabled N/A N/A 96280731 2384664381 111810385 2242382019
1 04:bd:88:cc:df:79 GE none enabled down 1 Gb/s full disabled N/A N/A 358979 72154395 185118 50330604
Cause
The Aruba AP225 is unique in that it has 2 H/W detectors for POE+. One is standards
compliant (802.3at) and the other is a pre-standard detector which is a basic voltage comparator set to
51V. If the line voltage is greater than 51V then we assume that the PSE is
802.3at compliant.
At version 6.5.0.4, the pre-standard detector was removed after reports of false positive resulting
in the switch constantly resetting the APs.
There are 2 inputs to the POE decision making:
a) A physical layer classification of the PSE (per 802.3 - 2009) involving a 2 event H/W test. For Cisco 3850 802.3at switches this result is
802.3af. This is what is being shown on the line "Current HW State". In other words if we only consider the H/W classification without LLDP,
we "would" adopt a restricted mode.
b) A data layer classification of the PSE (LLDP power over MDI TLV). We see below that LLDP negotiated 20.2W of power with the switch.
20.2W is what the AP-225 requested from the Cisco switch and the Cisco switch has granted that amount of power on the port to which the
AP is connected. Since the LLDP negotiation trumps the H/W classification result we adopt the unrestricted power mode.
Operational State POE-AT: No restrictions (Overridden by LLDP)
----------------- -------------------------------------------Current HW State POE-AF: One Ethernet port disabled; USB port disabled; 1x3 chain for 2.4GHz; 3x3 chain for 5GHz
LLDP Negotiated POE Power 20.2W
"Operation State" is the most important piece of information. This status indicates after weighing all inputs, in what power mode the AP is
operating with. In the
case above, it is operating in POE-AT mode meaning all features are
enabled. The AP LED should show Green (Full Power) versus Amber (Restricted).
Resolution
Make sure LLDP is enable on the Cisco 3850 802.3at switch port where the Aruba AP225 will be plugged.
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