iMessage Technology

iMessage Technology - iMessage is based on XMPP, the eXtensible Messaging and Presence Protocol specification related to PubSub or Publish and Subscribe, the same system that's used for push notifications. By building a unified XMPP notification system into iOS, Apple provides push notifications, push messaging, and FaceTime call notifications without having to keep multiple open connections to several different IM chat provider services, while also avoiding additional dependence upon a mobile account required by SMS.