Externalization of Packet Processing in Software Defined Networking.

Current SDN controllers aggregate all control plane subsystems into a monolithic program. A controller that follows the aggregated approach defines its own set of programming interfaces and services, making application development dependent on a particular SDN controller and restricting portability of management applications across controllers. We propose a new architecture that disaggregates controller functionality and externalizes packet processing, a critical first step towards migrating from a centralized, monolithic design to a decentralized microservice control plane architecture in which SDN controller functions are divided into a smaller, interconnected set. We argue that dividing a monolithic controller into smaller pieces has advantages.