Effect of competing TCP traffic on interactive real-time communication

Providing acceptable quality level for interactive media flows such as interactive video or audio is challenging in the presence of TCP traffic. 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 which increases the one-way delay for the media flow packets. 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-like traffic and long-lived TCP connections and highlight that current trend of using several parallel connections in Web browsers tends to have high cost on media flows. In addition, the recent proposal to increase the initial window of TCP to ten segments, if deployed, is going to make the jitter problem even worse.