Wireless Access

Dear Community Members,

 

I am doing an install of Aruba WiFi at a site, which has a mixture of Alcatel switches and Cisco Switches.

 

The Cisco switch they have is: 3560G-48PS-S

The Alcatel switch they have is: 6450-P48

 

This site has deployed AP-305’s everywhere. The Alcatel support 802.3at and the Cisco support 802.3af.

 

The problem I am having is that any AP that is plugged into the Cisco switch is running in power save mode.

If I take the same AP and plug it into the Alcatel switches they do not run in power save mode and run normally.

 

I have LLDP enabled on the Cisco switch not on the Alcatel switch. I turned this on to determine what the power consumption is of the AP.

 

On the Alcatel switch an AP 305 is consuming 6.7Watts and on the Cisco switch it is consuming 15Watts.

I have tried maxing out the power on the Cisco switch port, but this has made no difference.

 

Could you please confirm the following for me:

 

• Why is AP’s plugged into Alcatel switches using less power, but are running with no power issues?
• Why is the AP’s on the Cisco switch using twice as much power, but running in low power mode?
• As the AP’s are in low power mode, are any performances issues being experienced? I.e is 2.4/5GHz affected or do I have less spatial streams?
• Would installing a 802.3at switch resolve this issue?

 

I look forward to your responses.

 

Many Thanks,

My guess would be an issue with Cisco firmware, we've seen lots of cases with LLDP bugs in Cisco switches in properly negotiating power consumption with LLDP. However, the APs should run fine on 802.3af power.

 

Where/what are you looking at when you see power save mode for the APs? Low power mode on the AP just disabled the USB interface, which I'm sure you're not using.

 

Jerrod,

With POE (802.3af), the radios don't scale down on a 305 like the 225s do?

Not according to the DS.

That's what I thought. Was trying to make sure.


Pasquale Monardo
Conseiller Principal Solution Réseaux, Opération | Senior Network Solutions Consultant, Operation

T 514 385-4448 #204 DATAVALET.COM

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Hi,

I understand the explanation of the new firmware that may resolve the issue.

As my colleagues has also advised me that this has been seen recently.

Do you have any idea what firmware should the Cisco switch be running?

 

I have attached an output from one of the APs at the site that is in low power mode.

I believe only the USB port is disabled, however, can you confirm this for me please?

Power Status
------------
Item                        Value
----                        -----
Power Supply                : POE-AF
LLDP Power                  : 0.0W
Current Operational State   : USB port disabled

The only restriction is that the USB port is disabled while 802.3af is being provided.  If one of the radios were disabled or at lower power, it would say so in the "Current Operational State" section.  There is no advantage to powering this device using AT unless you are using the USB port.