POE Device HA with spanning tree or IP SLA

[beeraddd15]

Hi,

I'm looking for a HA solution for 2 wireless POE AP's on a tower (unreachable). 

Basically 1 AP will be powered on and transmitting, and I need to have the other AP powered off (POE off on switchport) but if the 1st AP drops (not pinging or interface down) then the 2nd AP on another switchport needs to have POE enabled to power on the AP and start transmitting.

How can this be achieved? I initially thought IP SLA but don't know whether this can trigger a POE inline command on a switchport.

Any advice would be greatly appreciated?

Cheers,

Brad

[Leo Laohoo]

Basically 1 AP will be powered on and transmitting, and I need to have the other AP powered off (POE off on switchport) but if the 1st AP drops (not pinging or interface down) then the 2nd AP on another switchport needs to have POE enabled to power on the AP and start transmitting.

What is the model of your PoE switch and does it even support IP SLA? 

You've need to factor in theft of your powered off AP and the potential issue when you power up your AP.  I am using different models of APs and something after a power reboot of the switch some APs just fail.  

I'm no big fan of what you're trying to do because it means you've got a second AP doing nothing.  Exactly what is the role of this AP that you really require a second unit not powered up?  Is it acting as an AP or a bridge?  Is your AP operating as a controller-based IOS or autonomous IOS? 

If I have a critical AP, I'd keep the spare nearby and the configuration ready.  I don't want it "out there" and powered off because I sure don't know if the AP has been stolen or dead.  

[beeraddd15]

Happy to purchase the required switch to do the job if possible.

Theft is not a problem - AP is 50m off the ground on a tower.

The AP's are acting in a WDS network and which these two AP's will participate. The HA part of the design needs this 2nd AP to be up an running as quick as possible if 1st AP fails.. acknowledging the fact that it's up on a tower and connected via POE to the switch.

2nd AP can't be on at the same time as it will wirelessly interfere with other AP.

I'm thinking IP SLA won't achieve what I want, maybe macro with a trigger event?

[Leo Laohoo · Accepted solution]

2nd AP can't be on at the same time as it will wirelessly interfere with other AP.

You're right about wireless channel interferrance but you can disable the radios.  This means the AP is powered but the not broadcasting any SSID. 

What you might want to do is an EEM script.  I don't build EEM script but what you might want to do is this kind of scenario: 

1.  If link to AP 1 is down/down then add the VLANs into the interface of AP 2.  

2.  If AP 1 link goes up/up, then wait for 5 minutes (wait for AP 1 to fully boot up) and then remove the allowed VLANs (except management VLAN) from AP 2 interface. 

Note, Catalyst 2K will never support EEM.  So you'll need to look at Catalyst 3K and up.  The "smallest" Catalyst 3K with PoE is the WS-C3560CG-8PS.  

[beeraddd15]

Perfect! never even knew about EEM.

That's the solution - EEM and IP SLA together.

- IP SLA to monitor the 1st AP interface and EEM to trigger commands to power on 2nd AP.

Thanks mate.

[Leo Laohoo]

Thanks for the rating. 

Move this thread to the EEM section and one of the EEM gurus can knock something up for you.