Software-Defined Networking: Challenges and research opportunities for Future Internet

Currently many aspects of the classical architecture of the Internet are etched in stone - a so called ossification of the Internet - which has led to major obstacles in IPv6 deployment and difficulty in using IP multicast services. Yet, there exist many reasons to extend the Internet, e.g., for improving intra-domain and inter-domain routing for high availability of the network, providing end-to-end connectivity for users, and allowing dynamic QoS management of network resources for new applications, such as data center, cloud computing, and network virtualization. To address these requirements, the next-generation architecture for the Future Internet has introduced the concept of Software-Defined Networking (SDN). At the core of this emerging paradigm is the separation and centralization of the control plane from the forwarding elements in the network as opposed to the distributed control plane of existing networks. This decoupling allows deployment of control plane software components (e.g., OpenFlow controller) on computer platforms that are much more powerful than traditional network equipment (e.g., switches/routers) while protecting the data and intellectual property of the vendors of such equipment. A critical understanding of this emerging paradigm is necessary to address the multiple challenges in realizing the Future Internet and to resolve the ossification problem of the existing Internet. To address these requirements, this paper surveys existing technologies and the wide range of recent and state-of-the-art projects on SDN followed by an in-depth discussion of the major challenges in this area. (C) 2014 Elsevier B.V. All rights reserved.