Method and apparatus for multi-cast based video conferencing

A video-conferencing system, comprising

• a communication network supporting multi-casting of an AVM stream from a multi-cast ("MC") server to a plurality of MC clients and a primary MC client participating in a video-conferencing session over point-to-multi-point connections,
• wherein the first plurality of MC clients are each participating in a first session, each MC client capable of receiving a selected AVM stream from the communication network and transmitting an associated AVM stream onto the communication network;
• wherein the primary MC client is participating in the first session, the primary MC client capable of receiving the selected AVM stream from the communications network and transmitting a default AVM stream onto the communications network from the primary MC client to the MC server over a point-to-point connection, and
• wherein the MC server provides the selected AVM stream to the first plurality of MC clients and the primary MC client via a first point-to-multi-point connection on said communications network, the MC server receiving the default AVM stream from the primary MC client and multi-casting the default AVM stream over the point-to-multi-point connections, said MC server switching between multi-casting the default AVM stream and a client AVM stream associated with any one of the MC clients granted permission to speak after the one of the MC clients has requested permission to speak wherein the client AVM stream is provided to the MC server via a dynamically created point-to-point link existing only for the duration of the client AVM transmission wherein the default AVM stream is maintained between the primary MC client and the MC server during the time the client AVM stream is transmitted to the MC server and wherein the dynamically created point-to-point link is torn down when the one of the MC clients is finished speaking and wherein the default AVM stream is then again multi-casted over the point-to-multi-point connection between the MC server and the plurality of the MC clients and the primary MC client.