What is iChat feature and it's use case?
When any Bonjour device sends out a mDNS response packet, AirGroup solution terminates that packet and updates its cache entries along with the device details. Such devices are identified as AirGroup Servers on a Mobility controller. When any Bonjour device sends out a mDNS query packet, AirGroup solution again terminates such packet and sends out a unicast response post cache entry lookup. Such devices are identified as Airgroup Users.
Some services use mDNS response packet to announce a user arrival and iChat is one of them. A new user entry will not be able to identify the existing user if the announcement packet(response packet) is not multicast. Hence the typical solution we use for airplay and other services does not hold good for iChat. The mDNS multicast response propagation allows services to multicast the response packet(it's a L2 multicast with service id "_presence._tcp"). This allows the existing users to instantly see a new user when a new user logs in. The mDNS response packet for iChat or Messages Application is multicast across all VLANs that are trunked in the controller.
How it works:
How to enable from WebUI:
How to enable from CLI:
(Aruba7210) (config) #airgroup service chat ?
disable disable service
enable enable service
(Aruba7210) (config) #airgroup service chat enable