Simple Gateway Control Protocol

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Simple Gateway Control Protocol (SGCP) is a communications protocol used within a Voice over Internet Protocol (VoIP) system. It has been superseded by MGCP, an implementation of the Media Gateway Control Protocol Architecture.

The Simple Gateway Control Protocol was published in 1998 by Christian Huitema and Mauricio Arango,[1] as part of the development of the "Call Agent Architecture" at Telcordia Technologies (formerly Bellcore). In this architecture a call-control elements, Media Gateway Controllers (MGCs) or the Call Agent, controls trunking, residential, and access-type VoIP "media gateways" and receives telephony signaling requests through a "signalling gateway".Although these gateways target different market segments, all of them convert time-division multiplexing (TDM) voice to packet voice. Later implementation of the architecture refer to the "Call Agent" as a "Softswitch".

SGCP was intended to be compatible with the Session Initiation Protocol (SIP), enabling the Call Agent to relay calls between a Voice over IP network using SIP and a traditional telephone network. The SGCP commands are encoded with a syntax somewhat comparable to the SIP or HTTP headers. They carry a payload describing the voice over IP media stream. This payload is encoded using the same "session description protocol" (SDP) as SIP.

SGCP was merged with the Internet Protocol Device Control (IPDC) proposal sponsored by Level3 Communications. This led to the definition of the Media Gateway Control Protocol Version 1.0, jointly submitted to the IETF by the authors of SGCP and IPDC in November 1998.

See also[edit]


  1. ^ Initial v1 draft, published on Christian Huitema's web site

External links[edit]

  • SGCP pages at Telcordia Description of SGCP and the call agent architecture.
  • [1] Simple Gateway Control Protocol (SGCP) Version 1.1 draft, July 30, 1998 by Mauricio Arango and Christian Huitema
  • [2] VoIp protocols -SGCP