Wireless Access

hi all,

This is a kind of mini (unofficial) advisory to help people avoid an outage, or better, resolve the issue quickly should they find themselves in it.

There is already a thread about this elsewhere in the forum (including most of the below info), but I plan to have this stickied at the top for a couple of weeks to help raise awareness and help avoid outages.

TL;DR; AP-51x requires 802.3at power or better (as noted in the datasheet) and should it not be present and Intelligent Power Management (IPM) is not enabled, the AP will be stuck in an inactive state post upgrade to 8.5.0.x (despite that it was working* in 8.4.0.x)

* When we say working in 8.4.0.x, well, that's kind of the problem, it wasn't really working "well". The radios had been shut down into 1x1 operation and the power LED would have been coloured amber and blinking once per 2 seconds the whole time to indicate something was amiss.

Read on below for the symptom, resolution and a workaround.

Symptom

Post upgrade to AOS 8.5.0.x previously operational AP51x APs are now stuck in inactive (according to show ap database), with the flag "If" (upper case I, lower case f):

(7008-core) [mynode] #show ap database

AP Database
-----------
Name   Group  AP Type  IP Address    Status           Flags  Switch IP 
----   -----  -------  ----------    ------           -----  ---------      ----------
ap515  lab    515      192.168.1.61  Up 10h:19m:3s    If     192.168.1.160

upon checking closer using the command show ap debug system-status ap-name <the ap> | begin "Power Status" we can find the reason:

(7008-core) [mynode] #show ap debug system-status ap-name ap515 | begin "Power Status"
Power Status
------------
Item                        Value
----                        -----
Power Supply                : POE-AF
LLDP Power                  : 0.0W
Current Operational State   : USB disabled, All radios disabled 
Eth0 HW POE status          : POE AF, LLDP power: 0.0W

refer to the "Current Operational State" which is "All radios disabled". 

The datasheet says:

* Operating the AP with an 802.3af (class 3 or lower) PoE source and IPM disabled is not supported

but in AOS 8.4 the AP was allowed to operate in a degraded manner as noted above. This has been rectified and enforced in AOS 8.5.

Unfortunately the only log message that is omitted is the following:

Jul 23 22:19:15  KERNEL(ap515@192.168.1.61): [ 2205.928006] Disabling USB power

which is both related (due to insufficient power) and unrelated (e.g. not causing any service impact) - this is clearly not informative enough and a bug has been raised internally to improve this going forward.

Resolution

The correct resolution for this issue is to ensure that the AP is connected to an 802.3at (or better) capable switch. If the AP is already on such a switch it may be that LLDP needs to be enabled so that the AP can learn about extra power available via LLDP "power-management" TLVs.

Once the AP is operating on 802.3at or better power, the power status should show the following:

(7008-core) [mynode] #show ap debug system-status ap-name ap515 | begin "Power Status"
Power Status
------------
Item                        Value
----                        -----
Power Supply                : POE-AT
LLDP Power                  : Successfully negotiated at 25.0W
Current Operational State   : USB port enabled 
Eth0 HW POE status          : POE AT, LLDP power: 25.0W

Workaround

As noted in the datasheet, the AP can run on 802.3af only when IPM is enabled. If the powering switch does not support 802.3at or there is no way to administratively enable LLDP, then you can enable IPM in order to bring the AP into service.

"ipm-enable" needs to be enabled in the relevant ap-system profile of the affected APs. Below is a CLI based example for ap system profile "default"

(7008-core) [mynode] #configure terminal ap system-profile default ipm-enable
(7008-core) ^[mynode] #write mem
(7008-core) [mynode] #
<wait a moment>

(7008-core) [mynode] #show ap debug system-status ap-name ap515 | begin "Power Status"
Power Status
------------
Item                        Value
----                        -----
Power Supply                : POE-AF
LLDP Power                  : 0.0W
Current Operational State   : 2.4GHz radio: No restrictions, 5GHz radio: No restrictions 
Eth0 HW POE status          : POE AF, LLDP power: 0.0W

please note the following comments about IPM from the datasheet:

* When powered by 802.3af (class 3) PoE and with the IPM feature enabled, the AP will start up in unrestricted mode, but it may apply restrictions depending on the PoE budget and actual power. What IPM restrictions to apply, and in what order, is programmable.

Wish I had seen this advisory last week. I managed to figure out on my own that the Inactive flag was power related. Tested my theory by enabling IPM and immediately the 515 sprang to life.

Did some reading on Cisco PoE...the switch will not give 30W unless LLDP is enabled.

I disabled IPM, enabled LLDP on the Cisco switch, the switch immediately gave 30W.

One additional thing to note is that the AP will reboot when the PSE changes from 15.4W to 30W. 

Would be really great if the Inactive flag had a reason attached in future!

I'm wondering if I do have a related issue, I have 5 515 APs and having some wifi issues, when I run the command:

show ap debug system-status ap-name AP_CastVPA_S1_248 | include "Power Status"

it says that the poe source is AP-AF and if I check the switch it says that is delivirin 12w. (as you can see in the images):

all the APs are connected to Aruba 2540 switch running software version YC.16.08 

do you think we need to do something so the Aps can draw 25watts?

thanks

hi cmedranosim2016, looks to me that everything is OK here for this AP-515 and its POE. The AP is aware that the switch can give 25W to the AP if it wants it ('successfully negotiated at 25.5W') but it just so happens that right this moment they are drawing around 11W. The 12W number showing is reserved POE power, it's not involved here in the operation of the AP.

Hi Guys,

I was facing kinda same issue,
Just wanna know, How much power does the AP-515 need on 802.3af ?,
Coz by enabling IPM still it is not becoming a part of the cluster and yellow light flashing as well.

Our switch is Entrasys c3g124, It does not support 802.3at.
And on high priority it is giving inlinepower of 9.6W. (Pic attached)

im still on 8.4.0.0,

Any idea ?

I believe it should be 13.5W on .af power.

• Maximum (worst-case) power consumption:
--DC powered: 16.0W
--PoE powered (802.3af, IPM enabled): 13.5W
--PoE powered (802.3at/bt): 20.8W

@Ovais Idrees

please look into the output of

show ap debug system-status ap-name ap515 | begin "Power Status"

for any clue. It could also be the ethernet link is not at 1Gbps.

PS. you really need to get up to 8.5.x as soon as possible for your AP515s.