RFC 1889 defines a protocol (RTP) for transporting real time audio and video data over a packet based network. In Fusion Voice over IP gateways, RTP endpoints are generally in point-to-point connections that transfer data between separate points on a network. However, Fusion also provides a mechanism for switching the data from a single RTP IPv4 or RTP IPv6 endpoint to multiple RTP IPv4 or IPv6 endpoints on the same gateway. Directing of a source RTP input stream to another RTP output stream is called RTP switching. Directing a single input RTP stream to multiple output RTP streams is called RTP forking. These capabilities permit applications to add functionality such as support for calling card services and call monitoring. The following illustration shows an example of RTP switching:
Fusion RTP switching channels consist of a single switch filter used to transfer data between separate RTP endpoints. When applications use an RTP switching channel to connect the two RTP endpoints, the channel transfers the voice packets received on one RTP endpoint to the other RTP endpoint without performing any data conversion tasks.