Super Slow Bonjour Fowarding Discovery

[ML]

We're a K-12 school with a bunch of Apple TVs deployed in classrooms (about 40), and they're segmented off on their own VLAN. We've setup a client-based wireless Group Policy (802.1X via Radius) that applies to staff accessing the wireless network. The Group Policy puts staff devices on their own, trusted VLAN and it also enables Bonjour Forwarding -- forwarding AirPlay from the service VLAN.

It all works -- except that Bonjour discovery is really, really slow and inconsistent. Once a client device associates with an AP, some Apple TV devices will start being discovered -- but it takes minutes (sometimes 5-10) for all of the devices to be discovered. And as soon as the client moves to a different AP (i.e., walks down the hall to a different classroom), the process starts again. Devices will also randomly disappear after being discovered.

The Apple TVs are connected to MS225 switches (ethernet), and our wireless users are connected to MR42 access points. The Apple TVs and APs may be connected to different switches, depending on the building. Bonjour discovery is being monitored via the AirPlay menu and the Tildesoft Discovery app. 

Any ideas on what might be happening?

[GIdenJoe]

Have you done a packet capture on your client to see after a roam the client is actually sending mDNS queries and the AP is not responding to them?

The AP should only hold the list of the mDNS services and respond to queries.

If they would time out on the AP then the AP's themselves are not listening to new discoveries.

If the client itself is timing out entries then you should really see if the client is actively trying to query for the entries.

Capture using capture filter host 224.0.0.251 on the client pc.