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Abstract：
Google proposed a new TCP congestion control algorithm (CCA), Bottleneck Bandwidth and Round-trip propagation time (BBR) which has opened up new dimensions in congestion control. BBR tries to operate near Kleinrock\'s operating point to avoid excessive queue formation at the bottleneck and to use the link bandwidth optimally. BBR creates a model of the network path by measuring the bottleneck bandwidth and minimum round-trip time (RTT) to maximize the delivery rate and minimize latency. BBR v2 is an updated version of BBR which addresses many shortcomings of the original BBR (BBR v1) such as interprotocol fairness, RTT fairness, and excessive retransmissions. However, BBR v2 has certain limitations in its operation in IEEE 802.11ac (Wi-Fi 5) networks. The default BBR v2 limits the throughput of Wi-Fi 5 and an increased latency has been observed. This is because the Wi-Fi 5 frame aggregation logic is underutilized and fewer frames are being sent to the Wi-Fi 5 interface. In this paper, we have proposed BBR-n (BBR new) which provides better throughput than the generic BBR v2 in the Wi-Fi 5 networks. Real-time experiments were performed over a physical testbed using Flent to confirm that BBR-n achieves over double throughput as compared to generic BBR v2 and reduced latency in networks as compared to pure loss-based variants such as Cubic and Reno.
摘要：
谷歌提出了一种新的TCP拥塞控制算法(CCA),瓶颈带宽和往返传播时间（BBR）为拥塞控制开辟了新的领域。BBR尝试在Kleinrock的操作点附近操作，以避免在瓶颈处形成过多的队列，并最佳地使用链路带宽。BBR通过测量瓶颈带宽和最小往返时间（RTT）来创建网络路径的模型，以最大化传输速率并最小化延迟。BBRv2是BBR的更新版本，它解决了原始BBR（BBRv1）的许多缺点，例如协议间公平性，RTT公平性,和过度的重新传输。然而,BBRv2在其在IEEE802.Ilac(Wi-Fi5)网络中的操作中具有某些限制。默认BBRv2限制了Wi-Fi5的吞吐量，并且观察到延迟增加。这是因为Wi-Fi5帧聚合逻辑未被充分利用并且较少的帧被发送到Wi-Fi5接口。在本文中,我们提出了BBR-n（BBR新），它比Wi-Fi5网络中的通用BBRv2提供更好的吞吐量。使用Flent在物理测试床上进行实时实验，以确认BBR-n与通用BBRv2相比实现了两倍的吞吐量，并且与纯基于损耗的变体（例如Cubic和Reno）相比，网络中的延迟减少了。
