Find Wireless Displays and Printers in different subnets

mDNS allows service based (as opposed to TCP port based) devices like Apple AirPlay, Google Chromecast, and Printers to be located across Subnet and VLAN boundaries. The problem is that these services are broadcast based and designed for small businesses or home use with only 1 VLAN. mDNS lets us propagate these advertisements across VLANs. The advertisements are small so propagating them does not cause a bandwidth issue and traffic after setup is routed TCP.