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Since the definition of the bufferbloat phenomenon, several Linux kernel modules have been introduced in its TCP/IP stack, and there is a lack of experimental studies on their effects when coupled with WLAN technologies, in particular, IEEE 802.11n and IEEE 802.11ac. One essential algorithm introduced is named TCP Small Queues (TSQ) and has the role of limiting the number of packets that a TCP socket can enqueue in the stack, waiting for the physical layer to send the packets before enqueueing extra data. A second significant TCP algorithm is named TCP Pacing (TP) and regulates the pace used by the socket to enqueue packets in the stack, regulating the formation of bursts of data. These mechanisms affect the frame aggregation logic on WLAN networks and compromise the throughput-latency tradeoff of all the TCP variants. This paper presents an experimental evaluation of these techniques investigating the wireless network performance of several TCP congestion control variants under the presence of different TSQ and TP policies, modeling also their interaction. [ABSTRACT FROM AUTHOR]

The FQ-CoDel queue management algorithm was recently published as an IETF RFC. It achieves low latency especially for low-volume (orsparse) traffic flows competing with bulk flows. However, the exact conditions for when a particular flow are considered to be sparse has not been well-explored. In this work, we analyze the performance characteristics of the sparse flow optimization of FQ-CoDel, formulating the constraints that flows must satisfy to be considered sparse in a given scenario. We also formulate expressions for the expected queuing latency for sparse flows. Then, using a numerical example, we show that for a given link and a given type of sparse flows (VoIP traffic), the number of sparse flows that a given bottleneck can service with low sparse flow latency is only dependent on the number of backlogged bulk flows at the bottleneck. Furthermore, as long as the maximum number of sparse flows is not exceeded, all sparse flows can expect a very low queuingqueuing latency through the bottleneck. [ABSTRACT FROM AUTHOR]