2802i and SG350 PoE Question

[derobbacher]

Hello WLAN experts,

recently we connected several 2802 WLAN APs  to a small Cisco Office Switch for testing PoE.

The small Cisco SG350 is offering 62 Watt PoE in total supporting 802.3af/at acc. to datasheet.

The datasheet for a 2802 WLAN AP  states 26 Watt with all features enabled except USB 2.0.

To my surprise, we could connect even 4 2802 APs  to this small Switch.

Show power Inline on the Switch shows only 9.9 Watt and Class 4 for each of them.

I guess we would have been bale to connect even more. But I had only for of them.

At first glance I did not notice any problem with this setup.

Does somebody know, which functions will not work on a 2802 with only 9,9 Watt instead

of supporting it with the officially annonced PoE+ with 26 Watt ?

Thank You in advance

Wini

P.S. we are running on 8.3.141 which show a nasty Full7Half-Duplex bug with 2802 APs.

[patoberli · Accepted solution]

I'm pretty sure that's a fault on the switch. The 2802, with the radios working, requires 26.1 Watts:

Module Available Used Remaining
(Watts) (Watts) (Watts)
------ --------- -------- ---------
1 740.0 413.2 326.8
Interface Admin Oper Power Device Class Max
(Watts)
..........
Gi1/0/47 auto on 26.1 AIR-AP2802I-E-K9 4 30.0

It is possible that yours has the radios disabled, because it's not getting enough power. In that case it's maybe happy with 9.9 W.

[derobbacher]

All 4 2802 are running with 9.9 Watt with all antennas active.

Greetings

Wini

[patoberli]

In that case it must be a visual error, because the AP clearly requires > 20 W to run correctly.

[KYLE MCLERREN]

The access point will power up and boot using only a small amount of PoE power, but unless it can get at least 26 watts, both of it's radios will be disabled. You'll see the light cycles through red/green/blue over and over when the radios are disabled. You wouldnt be able to tell this from the swtich side, youd need to look on your controller. 

Also, you can "Work around" that bug by setting logging level to 3. It doesnt stop it, but at least covers up the cosmetic issue.

[derobbacher]

Hello Kyle,

thank You very much for Your proposal to change Log-Level to avoid the

Full/Half-Duplex-Bug-Messages in the switch, when 2802i are connected.

Do You have some more detail info please on how this can be changed ?

Thank You very much

Wini