Impact of TCP on Interactive Real-Time Communication: Position Paper

Providing acceptable quality level for media flows such as interactive video or audio is challenging in the presence of TCP. Volatile TCP traffic such as Web traffic causes transient queues to appear and vanish rapidly introducing jitter to the packets of the media flow. Meanwhile long-lived TCP connections cause standing queues to form. To get insights into this problem space we conducted experiments in a real high-speed cellular network. Our results confirm the existence of issues with both Web traffic and long-lived TCP connections and highlight that the use of parallel connections in Web browsers has high cost on media flows. In addition, the recent proposal to increase initial window of TCP to ten segments, if deployed, is going to make the jitter problem even worse.