WLC 5520 HA

[craiglebutt]

We are currently going through a refresh program an looking to move to the 2800 AP and 5520 WLC

Currently we are using 3 * 8510HA which are great but can only go to 8.5 which the 2800 can connect on.

The 8510 is in a HA pair and works seamlessly if there is an issue, we want the same for the 5520, but everything looking at says there is no 5520 HA SKU.

So we have to move to smart licencing and the devices check in ever so often to see if we have the relevant licences.

My question is has anyone built a HA with 5520 with a seamless fail over of APs?

Is there a manual intervention if a WLC goes down and the APs tries to connect and if there is no licences on the WLC, will it APs join then the WLC will check to see if we have licences?

[balaji.bandi]

you should be ok. check the supported AP models and Version you using on WLC.

here is some reference guides

https://content.etilize.com/User-Manual/1030243086.pdf

https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-1/HA_SSO_DG/High_Availability_DG.html

[Scott Fella]

The 5520/8540/3504 does not have an ha sku. You just buy them and decide which one you want as primary and standby. This makes it easy for purchasing. You also just buy license for one wlc.

[craiglebutt]

Thanks for reply, just confirms what my concerns.

So if the primary fails, the APs will fail to secondary.

If the secondary box has no licences then the APs won't connect till it picks up the smart licences?

My concern is, we have 3 major sites, with 8510 in HA on each site with cross site fail over.

But moving to the 5520 we will have Primary and Secondary on 1 site and still have Tertiary fail over cross site

Does anyone know what are the timings for AP failing over from Primary to Secondary on same LAN?

cheers

[Scott Fella]

In SSO, the license moves and there is no outages. The license really isn’t an issue. Once you applied the AP count, the standby will have that information.

[Scott Fella · Accepted solution]

Let me add to what I was saying. If you run N+1 like you currently are doing, it is the same design. You set the backup as secondary unit. Only licensed controllers should have active aps not standby’s unless you had a failover. N+1 to SSO is a design change. If you plan on doing that, you must make sure you understand how failover works and where traffic gets places on the network. 

[patoberli]

The default heartbeat is 30 seconds for Primary and Secondary WLC (but this is not for HA-SSO). You can configure/change those settings under Wireless -> Access Points -> Global Configuration.
In case of a HA SSO and the primary WLC fails, the secondary will take over after 300 milliseconds. You can configure those settings under Controller -> Redundancy -> Global Configuration.

As far as I know, the AP will only change the WLC (in a HA-SSO setup), if the primary WLC is dead and the secondary takes over. In this case they immediately switch, as soon as the newly active WLC is active (virtual IP address will be moved to the other WLC, normally without any downtime, or a very small one). In the HA-SSO setup, the AP doesn't even realize it's switched the WLC.

[craiglebutt]

Thanks all for reply, much appreciated.