Cisco 8821 Manual page 93

The Cisco Autonomous Access Points utilize Inter-Access Point Protocol (IAPP), which is a multicast protocol, therefore
should use a dedicated native VLAN for Cisco Autonomous Access Points.
For the native VLAN, it is recommended to not use VLAN 1 to ensure that IAPP packets are exchanged successfully.
Port security should be disabled on switch ports that Cisco Autonomous Access Points are directly connected to.
Server groups for Wireless Domain Services must be defined.
Cisco Wireless IP Phone 8821 and 8821-EX Wireless LAN Deployment Guide
93