Experimental evaluation of less-than-best-effort TCP over 802.11 wireless networks

The majority of Internet traffic now involves wireless devices. Increasing use of online backup services and the popularity of user-generated content have increased the demand for bandwidth and may impact on delay-sensitive applications. Less-than-Best-Effort TCP congestion control mechanisms aim to minimise the impact of lower-priority applications on regular TCP traffic, but their performance over wireless networks is not well understood. We evaluate the performance of six Less-than-Best-Effort congestion control algorithms over 802.11n in a Linux testbed. We also consider the effect of high fixed-path delay on the performance of LBE mechanisms. The findings of this study suggest that Nice and CAIA Delay-Gradient (CDG) have the lowest impact on regular TCP traffic at low-delay settings, at the expense of reduced throughput. However, while CDG experiences even greater reductions to throughput in high-delay settings, Nice has a greater impact on regular traffic.