It reflects mDNS queries and responses among multiple LANs, which allows you to run untrusted IoT devices in a separate LAN but those devices can still be discovered in other LANs.

解决局域网跨 VLAN 服务发现难题，让你的 IoT 设备可以跨 VLAN 使用

https://www.v2ex.com/t/797091