Session Initiation Protocol (SIP), connection management protocol developed by the IETF; H.323, one of the first VoIP call signaling and control protocols that found widespread implementation. Since the development of newer, less complex protocols such as MGCP and SIP, H.323 deployments are increasingly limited to carrying existing long-haul network traffic. [citation needed] Media Gateway Control Protocol (MGCP), connection management for media gateways