Software-Defined Networking: State of the Art and Research Challenges (1406.0124v1)

Abstract: Plug-and-play information technology (IT) infrastructure has been expanding very rapidly in recent years. With the advent of cloud computing, many ecosystem and business paradigms are encountering potential changes and may be able to eliminate their IT infrastructure maintenance processes. Real-time performance and high availability requirements have induced telecom networks to adopt the new concepts of the cloud model: software-defined networking (SDN) and network function virtualization (NFV). NFV introduces and deploys new network functions in an open and standardized IT environment, while SDN aims to transform the way networks function. SDN and NFV are complementary technologies; they do not depend on each other. However, both concepts can be merged and have the potential to mitigate the challenges of legacy networks. In this paper, our aim is to describe the benefits of using SDN in a multitude of environments such as in data centers, data center networks, and Network as Service offerings. We also present the various challenges facing SDN, from scalability to reliability and security concerns, and discuss existing solutions to these challenges.

• The paper’s main contribution is its in-depth analysis of decoupling control and data planes in SDN to optimize network programmability and management.
• It evaluates the synergy between SDN and NFV, demonstrating how virtualization enhances flexibility, scalability, and efficient service provisioning in cloud environments.
• The paper addresses challenges such as controller reliability, latency, and security by proposing solutions like flow management distribution and controller clustering.

Overview of Software-Defined Networking: State of the Art and Research Challenges

The paper provides a comprehensive examination of Software-Defined Networking (SDN), its implications, benefits, challenges, and the potential integration with Network Function Virtualization (NFV). This paper is rooted in the context of evolving network demands driven by the proliferation of cloud computing, increased bandwidth requirements, and the dynamic nature of modern applications and services. SDN emerges as a crucial technology to address these challenges by decoupling the control and data planes, enabling centralized control and programmability of network infrastructures.

The paper highlights several key aspects of SDN:

1. SDN Architecture: SDN fundamentally changes network architecture by introducing a centralized controller that manages the network hardware, contrasting with the distributed intelligence model of traditional networks. The architecture involves OpenFlow as the communication protocol between the control and data planes, facilitating network programmability and application-specific control.
2. Network Virtualization Integration: While SDN operates independently from NFV, their conjunction promises significant advancements in network flexibility, scalability, and automation. Network virtualization overlays atop physical hardware, offering isolated networking environments conducive to innovation. The paper elaborates on network virtualizations' role in seamless VM migrations and effective management of hyper-scale data centers.
3. SDN Applications: SDN finds applications across various domains, notably in data center networks (DCNs) and Network-as-a-Service (NaaS) solutions. The paper investigates changes in DCN infrastructure brought about by SDN, such as enhanced scalability, energy efficiency, and improved management of network metrics like latency and bandwidth. Moreover, NaaS represents an abstraction of network capabilities for cloud environments, enhancing flexibility and control over network resources at the service level.
4. Challenges: SDN is not without challenges; issues of reliability, scalability, latency, and security are primary considerations. The paper explores these challenges, noting, for instance, the potential single point of failure in centralized SDN controllers and the scaling limitations posed by increased network size and flow rates. Attention is also given to controller placement strategies and the need for intelligent controller software to address security vulnerabilities.

The paper's insights into these SDN domains indicate practical steps towards resolving identified challenges. Techniques like distribution of flow management, controller clustering, and novel latency optimization mechanisms are explored as potential remedies. Furthermore, initiatives such as DevoFlow and DIFANE are referenced as solutions enhancing flow management and scalability.

Implications and Future Directions

The theoretical and practical ramifications of embracing SDN technology are profound. By transforming network infrastructure management, SDN can lead to streamlined operations, reduced operational costs, and accelerated deployment of innovative network services. Operationally, organizations could achieve new efficiencies in data center consolidation, agile service provisioning, and adaptive security practices.

Future developments in SDN will likely revolve around enhanced integration with NFV, broader deployment in wireless and wide area networks, and refined strategies for SDN controller implementation. Such progress will necessitate rigorous standardization efforts to ensure interoperability and consistent performance across diverse network environments. As SDN technology matures, it is expected to catalyze the next wave of network innovations, driven by dynamic service demands and evolving technological landscapes.

In conclusion, while SDN presents significant opportunities for modernization of network operations and management, addressing its inherent challenges remains pivotal in leveraging its full potential in enterprise and cloud networks.