In-network aggregation for data center networks: A survey

Aggregation applications are widely deployed in data centers, such as distributed machine learning and MapReduce-like framework. These applications typically have large communication overhead, which brings extra delay and traffic pressure to data center networks. In-network aggregation (INA) technology is a new approach to accelerate aggregation tasks and reduce traffic by offloading aggregation function on network switches. In this paper, we concentrate on two aspects of INA. The first aspect is INA implementation methods. We summarize key points of INA designing, and classify INA methods into three categories according to different types of hardware: commodity programmable switch, middle box and new switch architecture. The second aspect is INA algorithm. Building aggregation tree effectively is essential to the performance of INA. Finally, we make comparisons and propose some potential challenges and opportunities for future INA research.