The paper presents Data Center TCP (DCTCP), a TCP-like protocol designed to address the limitations of the standard TCP protocol in cloud data centers. These limitations arise from the high demand for small, predictable latency and large sustained throughput, which are often in conflict with the limited buffer space available in data center switches. The authors identify and analyze performance impairments in a 6000-server production cluster, including queue buildup, buffer pressure, and incast issues. DCTCP leverages Explicit Congestion Notification (ECN) to provide multi-bit feedback to end hosts, allowing for more precise congestion control. Evaluations at 1 and 10 Gbps speeds on commodity, shallow-buffered switches show that DCTCP delivers similar or better throughput than TCP while using 90% less buffer space. DCTCP also offers high burst tolerance and low latency for short flows, enabling applications to handle 10 times more background traffic without impacting foreground traffic. The paper discusses the design, implementation, and evaluation of DCTCP, highlighting its effectiveness in mitigating the performance issues in data center networks.The paper presents Data Center TCP (DCTCP), a TCP-like protocol designed to address the limitations of the standard TCP protocol in cloud data centers. These limitations arise from the high demand for small, predictable latency and large sustained throughput, which are often in conflict with the limited buffer space available in data center switches. The authors identify and analyze performance impairments in a 6000-server production cluster, including queue buildup, buffer pressure, and incast issues. DCTCP leverages Explicit Congestion Notification (ECN) to provide multi-bit feedback to end hosts, allowing for more precise congestion control. Evaluations at 1 and 10 Gbps speeds on commodity, shallow-buffered switches show that DCTCP delivers similar or better throughput than TCP while using 90% less buffer space. DCTCP also offers high burst tolerance and low latency for short flows, enabling applications to handle 10 times more background traffic without impacting foreground traffic. The paper discusses the design, implementation, and evaluation of DCTCP, highlighting its effectiveness in mitigating the performance issues in data center networks.