Abstract
Owing to powerful programmability, software defined networking (SDN) is well aligned with the requirements of NFV datacenters. Although the mainstream SDN frameworks can effectively respond to the requests of control plane, the load distribution among controllers is not balanced due to the request dynamics and request diversity. The existing solutions balance the load of control plane by migrating switches between controllers. However, these solutions are based on the binding between switches and controllers, so they are difficult to adapt to the dynamic and diverse requests. In this paper, we propose a new framework to decouple the binding. The new framework performs modular management for request queues. A complete request queue is provided for each type of request between each switch controller pair, so that the assignment between requests is independent of each other. Based on the proposed framework, we transform the request assignment problem into a variant of the scheduling problem in a Stochastic Processing Network (SPN), and propose a Maximum Pressure Policy (MPP) which can provide runtime guarantees on request throughput and response latency. To fit with the constraints inherent to large-scale deployment, we propose a distributed version of MPP, named DMPP. DMPP runs in local state on each switch and performs scheduling logic for batch requests. We implement a protosystem of our solution and evaluate it on the settings representing real-world scenarios. The results show that our solution can provide guarantees on request throughput and response latency, and significantly outperforms state-of-the-art solutions through a more efficient resource usage