Exploration of RTP Circuit Breaker with Applications to Video Streaming

Live multimedia streaming is becoming one of the dominant sources of internet traffic, much of which is sent over best-effort networks, i.e. along paths with a wide variety of characteristics. The multimedia traffic should be transmitted using a robust and effective congestion control mechanism to protect the network from congestion collapse. The RTP Circuit Breaker (RTP-CB) is a candidate solution that causes a sender to cease transmission when RTCP message feedback indicates excessive congestion. This paper studies RTP/UDP video traffic and the impact of its bursty behaviour on the network. It considers the potential limitations of using a RTP-CB with video traffic. We found that the bursty nature of a typical video flow can cause the RTP-CB to either prematurely cease transmission or to react too late. To reduce the likelihood of this happening, we suggest the use of a smoothing buffer in conjunction with the RTP-CB and propose design criteria for this buffer. Our experiments confirm the effectiveness of the proposed approach for different video streams.