Abstract

The idea of multi-connection congestion control was originally applied to aggregate flows passing from computer cluster to cluster communicating over the public Internet. This paper considers the extension of multi-connection streaming to wired/wireless networks and in doing so reviews theoretical results for multi-connection streaming, including virtual multi-connections within a single physical connection. Streaming a single video over multiple TCP-Friendly Rate Control connections is a promising way of separately coping with both wireless channel losses and traffic congestion, without the need for cross-layer intervention or retransmission delay at the data-link layer. At the same time, the wireless channel is properly utilized, as throughput improves with an increasing number of connections. Nevertheless, over IEEE 802.16e (mobile WiMAX) tuning is needed to select the number of connections and the Time Division Duplex (TDD) frame size. The paper assesses the impact on video quality of packet drops due both to channel loss over a WiMAX access link and router buffer overflow across an all-IP network, consisting of broadband wireless access and core network. The paper also considers end-to-end delay and start-up delay when employing several connections. Results show that provided the TDD frame size is selected appropriately then using multiple connections preserves video quality and improves wireless channel utilization, with a minimal impact on end-to-end delay. As a trade-off, there is an increase in start-up delay arising from the need to avoid possible buffer underflow.