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AP visibility and control in a HA Pair

AP visibility and control in a HA Pair

Andre_Brits_Kan
Contributor II

‎06-26-2017 11:10 AM

Hi Community

So I as part of a clients solution, we have deployed a High Available pair of C5210 controllers.
One controller is the primary and the other the backup.

All AP's home to the primary and also creates a backup tunnel to the backup controller.

When an AP fails over to the backup controller we see the following on the Primary controller:

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The AP indicates no channel or output power.
If you look at the AP reports on the controller it also indicates as Off.

If we look on the backup controller we do see the AP with the Channel info and transmit power info.

From the backup controller you can see the setting but not change anything again.

For the client this is very frustrating, he has to flip flop between controllers to get the full view and config.

What is your recommendations for managing this?

We also have no easy way of identifying what AP is connected to what Controller.
The only way to do this is to have a look at the AP availablility report, but the client has just over 1000 AP's and to find the specific one is not a quick process.

I would recommend they color code (Green and Blue) be added to the AP configuration list.
At least this is a quick way to see where the AP is currently homes too.
It would also be nice to be able to change AP config from any of the controllers.

Your comments?

10 REPLIES 10

Ronald_Dvorak
Honored Contributor

‎06-27-2017 08:24 AM

One question.... why do you use the feature and not legacy availability ?!
0 Kudos

Rey_Juan_Carlos
Contributor
In response to Ronald_Dvorak

‎06-27-2017 08:24 AM

Thanks Ronald for your help. Great post.
0 Kudos

Ronald_Dvorak
Honored Contributor
In response to Ronald_Dvorak

‎06-27-2017 08:24 AM

from the post above....
To enable legacy failover just remove the checkmark for fast failover.

Legacy failover is slower as the AP doesn't has a tunnel to the 2nd controller already established - slow means that you'd loose 1-2 pings during failover... in my experience.

The difference is that legacy failover has two requirements that MUST be fulfilled to allow the AP to authenticate/switch to the second controller.
1) the AP lose connection to the home controller
2) the controllers lose the connection to each other (=availability tunnel down)

Let's talk about the case in which you don't use legacy failiover.
If the APs connect via i.e. ESA0 and the availbility tunnel is configured on i.e. ESA1.
If ESA0 is down (i.e. broken cable) on the home controller the AP is not longer able to communicate with the controller but as ESA1 is still up (=availability tunnel is still up) the AP is not allowed to authenticate/switch to the second controller.

It's very important if you use legacy failover to use the same interface for AP registration also for the availabilty tunnel configuration.
In a "normal" setup with both controller in the same room and are setup for the same subnets that shouldn't be a problem and you are able to use legacy failover.

So the one thing that you need to make sure in the network design is that there is no such case where the AP is not able to reach the AP registration interface but the controllers could reach each other via the availabilty interface.

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GTM-P2G8KFN