Product and Software: This article applies to all Aruba controller platforms running ArubaOS 3.x and newer.
Aruba AP first tries packet size 1578. If that doesn't go through, the AP falls back to 1500. No other packet size in between will be tried.
This only applies to the GRE tunnel. Regular packets between the AP and the controller (for example, syslog) are not sent with large packet size.