The term Voice over IP (VoIP) is nearly synonymous with Internet Telephony. The majority of VoIP systems are designed to utilize separate signaling and media channels to provide calling services to users. The signaling channel is generally used to set-up, manage, and tear-down calls between two or more parties whereas the media channel is used to transmit the audio, video, or other media that may be associated with the call. A number of competing protocol standards exist for use as the VoIP system's signaling channel which include Session Initiation Protocol (SIP), H.323, Skinny, and many others. Real-time Transport Protocol (RTP), however, is used almost ubiquitously to provide VoIP systems with the required media channel.