Bonjour
Bonjour, formerly Rendezvous, is Apple Inc.'s trade name for its implementation of Zeroconf, a service discovery protocol used in Apple's Mac OS X operating system from version 10.2 onwards. Intended for use on local area networks, Bonjour uses multicast Domain Name System service records to locate devices such as printers, as well as other computers, and the services that those devices offer.
Protocol
The XMPP Standards Foundation worked with developers at Apple and several open-source projects to generate complete documentation of Bonjour messaging. The relevant specification is XEP-0174: Link-Local Messaging.