Abstract
1. Introduction
The continued development of microelectromechanical systems (MEMS) that continually record, process, and send information has brought about a considerable increase in the data traffic. In order to cover the increasing connectivity needs, the new sensor and mobile devices use multiple network infrastructures to send information (WiFi, 5G, LTE, WSN, and Bluetooth, among others). This new interconnected environment has led the origin of a new growing market scenario based on services and applications. However, the rigidity of actual network architectures, the dependency on a specific manufacturer or service provider, and the closed union between data and control planes in network infrastructures have limited the development applications in terms of scalability, mobility, security, energy efficiency, and quality of service (QoS).
In this context, the novel concept of Software Defined Networking (SDN) can help solve these limitations. SDN allows the centralized control of the network behavior through external software, separating the data and the control plane in network devices. This new paradigm can be extended to other network infrastructures, decoupling the transmission and control plane in base stations, access points, and wireless sensor agents. This new vision of software defined heterogeneous network opens new opportunities to share infrastructures and standardize interfaces, on-demand services, network programmability, and optimization of resources, novel services, and enhanced mechanisms for dynamic resource management. The present special issue reflects the last advances on research in the following fields: Software Defined Sensor Networks (SDSN), Software Defined Mobile Networks (SDMN), Novel 5G, SDN and NFV architectures, and integration of software defined technologies with traditional network architectures.
2. Related Works
M. M. Umar et al. presented a new hybrid routing protocol, named as State-Aware Link Maintenance Approach (SALMA). SALMA is based on Dynamic Source Routing (DSR) and Optimized Link State Routing (OLSR) protocols. The work also focuses on the activeness of nodes in the network operations and defines three states of nodes, that is, white, gray, and black. The work concludes that the proposed protocol gives improvements in some quality of service metrics like lower delay than DSR, lower routing overhead than OLSR, and lesser energy consumption by the network nodes.
P. Neves et al. proposed a novel EU H2020 SELFNET management framework upon the Software Defined and Virtualized Network paradigms. The SELFNET reference architecture is divided into Infrastructure Layer, Virtualized Network Layer, SON Control Layer, SON Autonomic Layer, NFV Orchestration and Management Layer, and Access Layer. The present architecture is advancing in following the challenging key performance indicator of the fifth generation (5G) system, where the network infrastructure becomes more heterogeneous and complex. The framework will assist network operators to simplify the key management tasks and save the man power. For example, SDN/NFV sensors that can monitor the network and SDN/NFV actuators that can perform corrective and preventive actions to mitigate existing or potential network problems can be automatically deployed. SELFNET aims to address three major network management concerns, that is, providing self-protection capabilities against distributed cyber-attacks, self-healing capabilities against network failures, and self-optimization features to dynamically improve the performance of the network and the QoE of the end users.
T.-W. Um et al. proposed Software Defined Networking- (SDN-) based active content networking architecture for future media environments. The proposed architecture aims to provide customized delivery of various types of media content in order to satisfy users' demand and service requirements. To this end, the authors have developed an active content processing model which provides in-network content processing through service objects that are integral parts of active content. The main benefits provided by the proposed model are high flexibility and creativity to meet the evolving future media environments.
J. Nightingale et al. introduce the SELFNET 5G project and describe the video streaming use case that will be used to demonstrate the self-optimizing capabilities of SELFNET's autonomic network management framework. SELFNET's framework will provide an advanced self-organizing network (SON) underpinned by seamless integration of Software Defined Networking (SDN), Network Function Virtualization (NFV), and network intelligence. The self-optimization video streaming use case is going beyond traditional quality of service approaches to network management. A set of monitoring and analysis components will facilitate a user-oriented, quality of experience (QoE), and energy-aware approach. Firstly, novel SON Sensors will monitor both traditional network state metrics and new video and energy related metrics. The combination of these low level metrics provides highly innovative health of network (HoN) composite metrics. HoN composite metrics are processed via autonomous decisions not only maintaining but also proactively optimizing users' video QoE while minimizing the end-to-end energy consumption of the 5G network. This contribution provided a detailed technical overview of this ambitious use case.
R. Huang et al. presented a software defined WSN (SDWSN) prototype to improve the energy efficiency and adaptability of WSNs for environmental monitoring applications, taking into account the constraints of WSNs in terms of energy, radio resources, and computational capabilities and the value redundancy and distributed nature of data flows in periodic transmissions for monitoring applications. The design enables a reinforcement learning based mechanism to perform value redundancy filtering and load-balancing routing according to the values and distribution of data flows, respectively, in order to improve the energy efficiency and self-adaptability to environmental changes for WSNs. The optimal matching rules in flow table are designed to curb the control signaling overhead and balance the distribution of data flows for achieving in-network fusion in data plane with guaranteed quality of service (QoS). Experiment results show that the proposed SDWSN prototype can effectively improve the energy efficiency and self-adaptability of environmental monitoring WSNs with QoS.