Zaheduzzaman Sarker, Varun Singh, and Colin Perkins
Proceedings of the IEEE Infocom Workshop on Communication and Networking Techniques for Contemporary Video,
Toronto, Canada,
April 2014.
DOI:10.1109/INFCOMW.2014.6849240
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. We briefly review the
design of the RTP circuit breaker, then present an initial evaluation
of its performance on LTE networks. Our results show that the algorithm
is conservative in overload situations with low delay and high loss.
Such situations can occur due to active queue management in LTE
networks. We propose changes to the RTP circuit breaker to better suit
such networks, by using a different TCP throughput model that is more
sensitive to the observed packet loss patterns.
Download: sarker2014circuitbreaker.pdf