Dynamic Switch-Controller Association and Control Devolution for SDN Systems

TL;DR

This paper introduces a dynamic scheme for switch-controller association and control devolution in SDN, improving scalability, reliability, and efficiency by adapting to traffic variations without prior traffic statistics.

Contribution

It presents an innovative online algorithm that jointly optimizes switch-controller association and control devolution, balancing costs and latency in SDN systems.

Findings

Lower communication and computation costs compared to static schemes.

Achieves balanced load distribution among controllers.

Reduces latency and improves system efficiency.

Abstract

In software-defined networking (SDN), as data plane scale expands, scalability and reliability of the control plane have become major concerns. To mitigate such concerns, two kinds of solutions have been proposed separately. One is multi- controller architecture, i.e., a logically centralized control plane with physically distributed controllers. The other is control devolution, i.e., delegating control of some flows back to switches. Most of existing solutions adopt either static switch-controller association or static devolution, which may not adapt well to the traffic variation, leading to high communication costs between switches and controller, and high computation costs of switches. In this paper, we propose a novel scheme to jointly consider both solutions, i.e., we dynamically associate switches with controllers and dynamically devolve control of flows to switches. Our scheme is an efficient online algorithm that does not need the statistics of traffic flows. By adjusting a parameter, we can make a trade- off between costs and queue backlogs. Theoretical analysis and extensive simulations show that our scheme yields much lower costs or latency compared to other schemes, as well as balanced loads among controllers.