To enable AirPrint through iPrint using multicast DNS (mDNS), your network must meet the following requirements:
Router or Gateway with an option to forward mDNS (Apple Bonjour) multicast advertisements on all or selected wireless VLANs
Wireless router that supports mDNS (Apple Bonjour) between wired and wireless machines
The wireless routers are expected to have the capability for IGMP snooping. IGMP snooping is required to disallow the multicast traffic on those network interfaces that are not participating in AirPrint's Bonjour multicast discovery.
The wireless network switches must not be interconnected for redundancy. This results in a Layer 2 switching loop.
Wireless network with no interconnection
IP Multicast network (IP Multicast must be enabled on network devices such as routers and switches)