Most Internet hosts today support multiple access technologies and network interfaces. Multipath transport protocols, like MPTCP, are being deployed (e.g., in smartphones), allowing transparent simultaneous use of multiple links. Besides providing increased resilience to link failures, multipath transports may better exploit available (aggregate) capacity across all interfaces. The safest way to ensure fairness is to assume that any subflows of a multipath end-to-end connection may share bottleneck links, but knowledge of non -shared bottlenecks could allow multipath senders to exploit more capacity without being unfair to other flows. The problem of reliably detecting the existence of (non)-shared bottlenecks is not trivial and is compounded by the fact that bottlenecks may change due to traffic dynamics. In this paper we focus on practical methods to reliably group flows that share, possibly dynamic, bottlenecks online and in a passive manner (i.e., without injecting measurement traffic). We introduce a novel dynamic clustering algorithm that we apply to update our previous shared bottleneck flow grouping (SBFG) method standardized by the IETF, based on delay statistics. We also adapt an offline SBFG method based on wavelet filters to enable it for online operation. These SBFG methods are evaluated by a simple testbed, rigorous simulation and real-world Internet experiments in a testbed comprised of multihomed hosts. Our results suggest that there is no clear winner, and selection of the “best” SBFG method will have to consider tradeoffs regarding accuracy, lag, and application requirements.

中文翻译：

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在线识别共享网络瓶颈的流组

如今，大多数Internet主机都支持多种访问技术和网络接口。诸如MPTCP之类的多路径传输协议正在部署中（例如，在智能手机中），从而允许透明地同时使用多个链接。除了提供增强的链路故障恢复能力之外，多路径传输还可以更好地利用所有接口上的可用（聚合）容量。确保公平的最安全方法是假设多路径端到端连接的任何子流都可能共享瓶颈链接，但是非 共享的瓶颈可能使多路径发送者可以利用更多的容量，而不会对其他流产生不公平的影响。可靠地检测（非）共享瓶颈的存在的问题并非微不足道，并且瓶颈可能因交通动态而改变，这一事实使问题变得更加复杂。在本文中，我们将重点放在实用的方法上，以可靠的方式将在线共享的，可能是动态瓶颈的流量可靠地分组，并以被动方式（即，不注入测量流量）。我们介绍了一种新颖的动态聚类算法，该算法可用于更新基于延迟统计信息的IETF标准化的先前共享瓶颈流分组（SBFG）方法。我们还调整了基于小波滤波器的离线SBFG方法，使其能够在线运行。这些SBFG方法通过一个简单的测试台进行评估，在由多宿主主机组成的测试平台中进行严格的模拟和真实的Internet实验。我们的结果表明，尚无明确的赢家，选择“最佳” SBFG方法将必须考虑准确性，滞后性和应用要求方面的权衡。