The emergence of two new technologies, namely, software defined networking (SDN) and network function virtualization (NFV), have radically changed the development of network functions and the evolution of network architectures. These two technologies bring to mobile operators the promises of reducing costs, enhancing network flexibility and scalability, and shortening the time-to-market of new applications and services. With the advent of SDN and NFV and their offered benefits, the mobile operators are gradually changing the way how they architect their mobile networks to cope with ever-increasing growth of data traffic, massive number of new devices and network accesses, and to pave the way toward the upcoming fifth generation networking. This survey aims at providing a comprehensive survey of state-of-the-art research work, which leverages SDN and NFV into the most recent mobile packet core network architecture, evolved packet core. The research work is categorized into smaller groups according to a proposed four-dimensional taxonomy reflecting the: 1) architectural approach, 2) technology adoption, 3) functional implementation, and 4) deployment strategy. Thereafter, the research work is exhaustively compared based on the proposed taxonomy and some added attributes and criteria. Finally, this survey identifies and discusses some major challenges and open issues, such as scalability and reliability, optimal resource scheduling and allocation, management and orchestration, and network sharing and slicing that raise from the taxonomy and comparison tables that need to be further investigated and explored.

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SDN/NFV-Based Mobile Packet Core Network Architectures: A Survey

A survey on software defined networking with multiple controllers

In recent years, Software Defined Networking (SDN) has emerged as a pivotal element not only in data-centers and wide-area networks, but also in next generation networking architectures such as Vehicular ad hoc network and 5G. SDN is characterized by decoupled data and control planes, and logically centralized control plane. The centralized control plane in SDN offers several opportunities as well as challenges. A key design choice of the SDN control plane is placement of the controller(s), which impacts a wide range of network issues ranging from latency to resiliency, from energy efficiency to load balancing, and so on. In this paper, we present a comprehensive survey on the controller placement problem (CPP) in SDN. We introduce the CPP in SDN and highlight its significance. We present the classical CPP formulation along with its supporting system model. We also discuss a wide range of the CPP modeling choices and associated metrics. We classify the CPP literature based on the objectives and methodologies. Apart from the primary use-cases of the CPP in data-center networks and wide area networks, we also examine the recent application of the CPP in several new domains such as mobile/cellular networks, 5G, named data networks, wireless mesh networks and VANETs. We conclude our survey with discussion on open issues and future scope of this topic.

A Survey on Controller Placement in SDN

Software-defined networking (SDN) is an emerging network architecture that promises to simplify network management, improve network resource utilization, and boost evolution and innovation in traditional networks. The SDN allows the abstraction and centralized management of the lower-level network functionalities by decoupling the network logic from the data forwarding devices into the logically centralized distributed controllers. However, this separation introduces new scalability and performance challenges in large-scale networks of dynamic traffic and topology conditions. Many research studies have represented that centralization and maintaining the global network visibility over the distributed SDN controller introduce scalability concern. This paper surveys the state-of-the-art proposed techniques toward minimizing the control to data planes communication overhead and controllers' consistency traffic to enhance the OpenFlow-SDN scalability in the context of logically centralized distributed SDN control plane architecture. The survey mainly focuses on four issues, including logically centralized visibility, link-state discovery, flow rules placement, and controllers' load balancing. In addition, this paper discusses each issue and presents an updated and detailed study of existing solutions and limitations in enhancing the OpenFlow-SDN scalability and performance. Moreover, it outlines the potential challenges that need to be addressed further in obtaining adaptive and scalable OpenFlow-SDN flow control.

Toward adaptive and scalable openflow-SDN flow control: A survey

Software Defined Networking simplifies design, monitoring and management of next generation networks by segregating a legacy network into a centralized control plane and a remotely programmable data plane. The intelligent centralized SDN control plane controls behavior of forwarding devices in processing the incoming packets and provides a bird-eye view of entire network at a single central point. The centralized control provides network programmability and facilitates introduction of adaptive and automatic network control. The SDN control plane can be implemented by using following three deployment models: (i) physically centralized, in which a single SDN controller is configured for a network; (ii) physically distributed but logically centralized, wherein multiple SDN controllers are used to manage a network; and (iii) hybrid, in which both legacy distributed control and centralized SDN control coexist. This manuscript presents all these control plane architectures and discusses various SDN controllers supporting these architectures. We have analyzed more than forty SDN controllers in terms of following performance parameters: scalability, reliability, consistency and security. We have examined the mechanisms used by various SDN controllers to address the said performance parameters and have highlighted the pros and cons associated with each mechanism. In addition to it, this manuscript also highlights number of research challenges and open issues in different SDN control plane architectures.

Scalability, Consistency, Reliability and Security in SDN Controllers: A Survey of Diverse SDN Controllers

Software-defined networking offers several benefits for networking by separating the control plane from the data plane. However, networks’ scalability, reliability, and availability remain as a big issue. Accordingly, multicontroller architectures are important for SDN-enabled networks. This paper gives a comprehensive overview of SDN multicontroller architectures. It presents SDN and its main instantiation OpenFlow. Then, it explains in detail the differences between multiple types of multicontroller architectures, like the distribution method and the communication system. Furthermore, it provides already implemented and under research examples of multicontroller architectures by describing their design, their communication process, and their performance results.

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An Overview on SDN Architectures with Multiple Controllers

Software Defined Networking is changing entirely the network architecture and moving it forward to make it more flexible, scalable, fast, and highly available. Recently, the idea of containerization is becoming more present in the industry as well as in the academia and has managed to solve many issues linked to virtual machines. SDN has begun with a centralized architecture with a single controller that is responsible for the entire underlying network, thereafter, this solution has shown many overall performance related problems. After that, the need has raised for distributed SDN networks to obstruct the limitation of performance, security, and scalability. In this paper, we try to take advantage of both notions already addressed, the containerization concept, as well as the control plane distributed SDN networks concept and propose DockFlex, a distributed control plane Docker-based SDN architecture that inherits all the features of a classic SDN architecture and, furthermore, enables a highly manageable and orchestrated multicontroller SDN network that can be established easily via the cloud. Moreover, we suggest a highly customizable implementation of the DockFlex architecture, which uses native Docker-based tools and third-party solutions.

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DockFlex: A Docker-based SDN Distributed Control Plane Architecture

Multi-controller architectures have become very necessary for software-defined networks to provide more efficiency, scalability, flexibility and security. However, the controllers must be interconnected in a way that aims to improve the overall performance. In this paper, we propose the OMCH-SDN, an Overlay Multi-Controller Hypercube-based topology to interconnect controllers by using a Hypercube pattern to take advantage of its various mathematical characteristics. The proposal for this research is evaluated through simulations of a real overlay network. The results show that the OMCH-SDN model shows better results concerning the synchronization delay, the throughput as well as the end-to-end latency comparing to a flat-based SDN multi-controller topology. Keyword SDN, Multi-controller architecture, Hypercube-based topology

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Othmane Blial

Papers

An Overview on SDN Architectures with Multiple Controllers

DockFlex: A Docker-based SDN Distributed Control Plane Architecture

OMCH-SDN: An Overlay multi-controller Hypercube-based topology for Softwaredefined Networks