Ubiquiti Best Practices for Managing AirPlay Chromecast on UniFi Network

This article explains best practices for configuring larger UniFi networks with AirPlay/Chromecast devices. For efficient and reliable channel utilization, networks with more than 100 WiFi clients will need the multicast block option to be enabled on each of their SSIDs. This guide is especially useful for schools, stadiums, public venues, or similar networks.

Note: This guide applies to a network with a UniFi Security GatewayUDM, or UDM-Pro. If your network does not have one of these, the steps may need to be adapted. 

Creating a ChromeCast/AirPlay Network

Once your UniFi Network scales beyond a certain number of WiFi clients, it is important to ensure that every AP’s WiFi channel continues to be used efficiently. The broadcast traffic from more than 100 clients is typically high enough that WiFi performance may start to degrade. We always recommend enabling the multicast block option setting for larger networks.

However, this option causes a problem with users that would like to use their ChromeCast/AirPlay devices on the same WiFi network, because those devices will no longer hear the MDNS broadcasts from other devices on the network. They will no longer be discoverable.

In order to gain the performance benefits of multicast block while still maintaining discoverability to these WiFi clients, please follow these steps:

  1. Go to Settings > WiFi and select on the SSID to check that multicast block is enabled if it has more than 100 clients on it.
  2. Create a separate SSID/VLAN for the ChromeCast/AirPlay clients.
    1. Go to Settings > Networks, and add a New Network.
    2. Go to Settings > WiFi, and add a new WiFi Network, ensuring that the Network from Step “a” is selected, instead of LAN.
    3. Go to Settings > Advanced Features > Advanced Gateway Settings > Multicast DNS and enable Multicast DNS, then click Apply Changes.
  3. Forget the old network on your ChromeCast/AirPlay clients and connect them to the new WiFi Network.
  4. Test Discoverability from the appropriate mobile apps.

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