Product and Software: This article applies to all Aruba Mobility Controllers and ArubaOS 3.x and later.
Channel switch announcement (CSA) is part of 802.11h.
When an AP changes channel, it advertises certain information in Element ID=37 to indicate which channel it is going to and when.
This information helps the client to jump to the same channel and saves scanning time.
Not all client drivers support this feature, however, the latest drivers from Atheros, Broadcom, and Intel support this feature.