In recent years several multipath data transport mechanisms, such as MPTCP and XMP, have been introduced to effectively exploit the path diversity of data center networks (DCNs). However, these multipath schemes have not been widely deployed in DCNs. We argue that two key factors among others impeded their adoption: TCP incast and minimum window syndrome . First, these mechanisms are ill-suited for workloads with a many-to-one communication pattern, commonly found in DCNs, causing frequent TCP incast collapses. Second, the syndrome we discover for the first time, results in 2-5 times lower throughput for single-path flows than multipath flows, thus severely violating network fairness.

To effectively tackle these problems, we propose AMP: an adaptive multipath congestion control mechanism that quickly detects the onset of these problems and transforms its multipath flow into a single-path flow. Once these problems disappear, AMP safely reverses this transformation and continues its data transmission via multiple paths. Our evaluation results under a diverse set of scenarios in a fat-tree topology with realistic workloads demonstrate that AMP is robust to the TCP incast problem and improves network fairness between multipath and single-path flows significantly with little performance loss.

近年来，已经引入了几种多路径数据传输机制，例如MPTCP和XMP，以有效利用数据中心网络（DCN）的路径多样性。但是，这些多路径方案尚未在DCN中广泛部署。我们认为，除其他因素外，有两个关键因素阻碍了它们的采用：TCP内插和最小窗口综合症。首先，这些机制不适用于通常在DCN中发现的具有多对一通信模式的工作负载，从而导致频繁的TCP内播崩溃。其次，我们首次发现的综合症导致单路径流的吞吐量比多路径流的吞吐量低2-5倍，从而严重违反了网络公平性。

为了有效解决这些问题，我们提出了AMP：一种自适应多路径拥塞控制机制，该机制可快速检测到这些问题的发生并将其多路径流转换为单路径流。一旦这些问题消失，AMP将安全地逆转此转换并继续通过多条路径传输数据。我们在具有实际工作负载的胖树拓扑中的各种场景下评估的结果表明，AMP对TCP内插问题具有鲁棒性，并在不损失性能的情况下显着提高了多路径和单路径流之间的网络公平性。