Yes, they are using Airgroup, and they complain about occasionally loss of connection with some production servers used for file storage every day.
By digging into a packet capture, I noticed there are too many multicast packets including mDNS and IPv6. I made some ACLs in the access switches to screen out IPv6 packets which are not useful to their services. It seems to work out a little bit, so I wonder whether there is a further way to reduce mDNS cast in the network, even though I can't screen them all as Bonjour is one of their services.
I noticed there is a command in CLI reference which seems to indicate Airgroup is able adjust the rate of mDNS it sends out, so I think it might help if it works as I assumed. Just for discretion before I put it into production configuration
BTW, I have advised them to think about segment users by more vlans, however, this customer is lack of motivation to do so as the environment is already in production