3. Software-Defined Networks Principles and Use Case Scenarios

With the emerging services and business models driven by open devices and applications (app stores), service providers are faced with new challenges of reducing total cost of ownership (TCO), improve average revenue per user (ARPU), and customer retention. The software defined networking (SDN) paradigm provides a promising way to address these challenges with four fundamental principles, viz., decoupling of control and forwarding planes for improved scaling to reduce TCO, open APIs for network programmability/flexibility for service velocity and innovation, network virtualization for resource optimization and open flow for intelligent flow management. In this chapter, we provide a review of the SDN technology and business drivers, describe the high-level SDN architecture and principles, and give three scenarios of its use cases in mobile access aggregation networks and the cloud networks. Furthermore, we provide discussions on the design implementation considerations of SDN in the mobile networks and the cloud, in comparison with traditional networks.