Migrating to SDN for Mobile Core Networks: A Dynamic and Global Perspective

Abstract

The rapid growth of mobile traffic and the vast variety online activities demand enhancement of mobile networks. Software-Defined Networking (SDN) is considered a promising solution for the core network. But upgrading to SDN from a legacy network is a multi-period process. From both dynamic and global perspectives, during the migration it needs to simultaneously consider optimizing the local goal at each intermediate step and the global goal. This involves in some essential questions that have to be answered: which legacy devices to upgrade and when to, and how to place controllers. Due to interaction between the local goals and the global goal, however, to answer these questions together is challenging. In this paper we study the SDN migration problem and answer all of these questions together. We formulate the SDN migration problem as a time-varying dual-objective dynamic optimization model, in which the timing factor is taken into account, and the objective of optimization varies with time. Then we introduce a penalty item to convert the dual-objective dynamic optimization problem to a series of single step optimization problems that can be solved directly by CPLEX for small scale networks. The simulation results based on real network topology show that our model can obtain a tradeoff between the local goals and global one.