http://www.rfc-editor.org/rfc/rfc3920.txt
RFC 3920: Extensible Messaging and Presence Protocol (XMPP): Core, P. Saint-Andre2004-10-01T23:00:00-00:00This memo defines the core features of the Extensible Messaging and Presence Protocol (XMPP), a protocol for streaming Extensible Markup Language (XML) elements in order to exchange structured information in close to real time between any two network endpoints. While XMPP provides a generalized, extensible framework for exchanging XML data, it is used mainly for the purpose of building instant messaging and presence applications that meet the requirements of RFC 2779. [STANDARDS-TRACK]