Many-to-one traffic pattern in datacenter networks introduces the problem of Incast congestion for Transmission Control Protocol (TCP) and puts unprecedented pressure to the cloud service providers. To address heavy Incast, we present an Receiver-oriented Datacenter TCP (RDTCP). The proposal is motivated by oscillatory queue size when handling heavy Incast traffic and substantial potential of receiver in congestion control. Finally, RDTCP adopts both open- and closed-loop congestion controls. We provide a systematic discussion on its design issues and implement a prototype to examine its performance. The evaluation results indicate that RDTCP has an average decrease of 47.5% in the mean queue size, 51.2% in the 99th-percentile latency in the increasingly heavy Incast over TCP, and 43.6% and 11.7% over Incast congestion Control for TCP (ICTCP).