Great question Marco,
It depends on the type of WLAN authentication used is a short answer. APs will
recognize when the primary ZD is no longer available, and will connect with the new
ZD, and reboot when provisioned by it. WLANs are redeployed every time the AP
has to re-join a ZD, whether by SR, forced failover, or pulling the plug on active ZD.
The typical AP reconnect and resume service period might be 15-20 seconds.
SR ZD pairs share some client state information, like web-auth, but do not share
802.1x states, meaning clients will need to fully re-auth thru RADIUS if they were
using 802.1x. There is ongoing development to share these client states too, but
we're not there yet.