I have a customer who has an abundance of 2504 HA WLCs (AIR-CT2504-HA-K9) and would like to deploy these as mobility anchor controllers for an upcoming project. My initial thoughts were that this will be OK as no APs are terminated on the anchor. However I'm not so sure if there would be any other limitation preventing it being an anchor controller such as a restriction on being able to terminate the EoIP tunnel from the internal controllers.
Has anyone ever deployed a 2504 HA controller as a standalone anchor WLC?
Real "HA" (active/standby with session synchronization) is not possible with 2504 WLC's. With previous code it was not even possible to use 2504's as anchor controller but that changed since 8.x code.
So, what can you do with two 2504's? Configure them independently in another mobility domain than your current WLC's (for example "anchor") so that other AP's don't learn about them. Build mobility tunnels between your current WLC's and both anchor's by adding them in the "mobility group lists". Basically create a full mesh of tunnels. You can then configure both anchors WLC's under the SSID on your internal WLC's. Under "Mobility Anchor Config" you can configure the keep alives used to trigger fail-overs if one of your anchor WLC's fails.
If you need more than 1Gbit/s aggregated throughput you can configure LAG with port-channels.
