Containerization technology is being adopted quickly by the software industry because it offers fast deployment, good portability, and high resource efficiency to run large-scale and distributed systems. For example, many large Internet companies, e.g. Google, Yelp and AirBnB, etc., have intensively used containers to speed up the development of their applications and platform. The ecosystem of containerization is also rapidly growing. For instance, operating system providers like Microsoft and RedHat have released features to support Docker/container in Windows and Linux respectively; cloud providers like AWS, Azure and OpenStack all release their own services and solutions for containerized applications; there are about 400,000 public container images on Docker Hub with roughly 4~5 thousand new ones per week, and the number of pulls from Docker Hub reached 1 billion from Aug to Oct, 2016.

However, containerization is still in its early stage, and one of the major challenges it is facing is networking. Current container networking solutions mainly rely on the OS kernel to provide basic reachability and security among containers, while failing to meet various requirements needed by practical applications. For example, performance sensitive applications demand high networking performance (e.g. high bandwidth and low latency), while security sensitive applications usually rely on the network to implement firewalls, Intrusion detection system (IDS) or traffic scrubbers. Moreover, there are application demands for privacy, fairness, mobility, high availability, and so on and so forth. It is still challenging to provide the network functions above in container networking due to concerns such as scalability with the number of containers, containers portability, the underlying environments containers depend on (on physical machines or virtual machines) and the heterogeneity of end points (e.g. containers, VMs and physical machines).