ARCHITECTURE

The Mobicents Media gateway consist of three levels: media processing layer, management layer, and control layer.

The first layer is media processing layer. This layer is a collection of endpoints. Each endpoint is a sources or a sinks of data and can be physical or virtual. Physical Endpoint requires hardware installation – PSTN card for example. Each digital channel of that card may be configured as an endpoint. To establish communication between endpoints or between endpoint and other entity in the IP network via RTP endpoint uses connections. At the core of the connection is signal processing. This is performed by Digital Signal Processors to provide the traffic interface between the Internet and the wireless network of the PSTN, and to convert Time Domain Media (TDM) voice to VoIP and back. This process is time-dependent and the system must re-assemble packets in their time-stamped sequence. When packets are missing or late,the media gateway discards and interpolates them. The media compresses voice packets, corrects for jitter, cancels echoes, and generates or recognizes tones. The DSP may be implemented by harware or based on Java Media Framework.

The second layer is management layer. As mentioned above, the media processing layer is a collection of endpoint. Each endpoint should be configured, started, monitored and stopped when endpoint.is out of service. To achieve these goals Java Managed Extension API is adopted. So each endpoint is implemented as Mbean. Any stanadard JMX tools can be used for management perpouses.

Third layer is control protocol layer. Media gateways focuses on media processing tasks and ussualy is not involved to call setup process. Media gateway is passive entity wich is controlled by external call agant (CA) or call controller. Mobicents media gateway is designed to support a wide variety of control protocols. Since control protocols work asynchronously, each is implemented as JSLEE application. -- Main.kulikoff - 22 Apr 2007