OSDT: A Scalable Application-Level Scheduling Scheme for TCP Incast Problem

TCP Incast refers to the phenomenon of goodput collapse when multiple synchronized servers send data to the same client in parallel. In this paper, we propose a novel application-level scheduling approach named OSDT (Optimal Staggering Data Transfers) for TCP Incast problem. OSDT limits the number of concurrent TCP flows as well as servers' sending rate to optimal values so that the utilization of link capacity can be maximized without any packet losses. To achieve this, we build an optimization model with the usage of network and application information. Based on this model we can get the optimal values for the parameters in OSDT. Simulation results indicate that OSDT can achieve the highest goodput among all existing application-level scheduling approaches in a wide range of network and application parameters, and its performance is stable. So OSDT can be seen as an effective and scalable solution for TCP Incast problem.