Architecture and design of an enhanced H.323 VoIP gateway

This paper presents the architecture and design of an enhanced VoIP gateway based on the H.323 protocol. The key characteristics of this gateway include: scalability by separating signaling from media transformation and use of media gateway control protocols such as MGCP/MEGACO for communication between the signaling part and the media gateway; lightweight property by using the transport protocol SCTP (stream control transmission protocol) to convey H.323 and MGCP/MEGACO signaling; QoS support through the control of the voice encoding of the VoIP connections. This control is accomplished by estimating the network load and enforces the voice connections to modify the encoding scheme according to the estimated network load.