An Evaluation of RTP Circuit Breaker Performance on LTE Networks

Our paper on An Evaluation of RTP Circuit Breaker Performance on LTE Networks will be presented in the IEEE Infocom Workshop on Communication and Networking Techniques for Contemporary Video in Toronto, Canada, in April 2014.

Real-time multimedia comprises a large, and growing, fraction of mobile data traffic. An important subset of such flows are from interactive conferencing applications using RTP on UDP/IP to reduce latency. UDP has no congestion control, and while the IETF is developing RTP-level congestion control algorithms as part of the WebRTC standards, these will take time to finalise and deploy. In the interim, we proposed an RTP circuit breaker to the IETF. This can detect and stop RTP flows that cause excessive network congestion, acting as an envelope within which a congestion control algorithm can operate. In this paper, we review the circuit breaker design, and present an initial performance evaluation on LTE networks. The algorithm is shown to be conservative in overload situations with low delay and high loss, which can occur due to AQM in LTE networks. We propose changes to the circuit breaker to better suit such networks.

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