Software-defined networking (SDN) has attracted the attention of the research community in recent years, as evidenced by a large number of survey and review papers. The architecture of SDN clearly recognizes three planes: application, control, and data planes. The application plane executes network applications, the control plane regulates the rules for the entire network based on the requests generated by network applications, and based on the set rules, the controller configures the switches in the data plane. The role of the switch in the data plane is to simply forward packets based on the instructions given by the controller. By analyzing the SDN-related research papers, it is observed that research, from the very beginning, is insufficiently focused on the data plane. Therefore, this paper gives a comprehensive overview of the data plane survey with a particular emphasis on the problem of programmability and flexibility. The first part of the survey is dedicated to the evaluation of actual data plane architectures through several definitions and aspects of data plane flexibility and programmability. Then, an overview of the SDN-related research was presented with the aim of identifying the key factors influencing the gradual deviation from the original data plane architectures given with ForCES and OpenFlow specifications. In this paper, we used the term data plane evolution for this deviation. By establishing a correlation between the treated problem and the problem-solving approaches, the limitations of ForCES and OpenFlow data plane architectures were identified. Based on the identified limitations, a generalization of approaches to addressing the problem of data plane flexibility and programmability has been made. By examining the generalized approaches, open issues have been identified, establishing the grounds for future research directions proposal.

In order to ensure the required wireless communication system performances, it is necessary to have an efficient communication channel model, which is capable of considering all channel degradation factors fairly. In this paper, a unified hollow-disk geometrically based stochastic channel model is derived. This model assumes that the scatterers are distributed in a hollow-disk area around a mobile station. Namely, the scatterer distribution is derived as a projection of $\boldsymbol{d}$-dimensional uniformly distributed scatterers into two-dimensional space. According to this generalization, derived model is capable of obtaining uniform circular, uniform ring, uniform hollow-disk, and unified disk scattering model as special cases, as well as modeling a whole new group of hollow-disk models. Under an assumption of single bounce scattering and omnidirectional antennas at transmitter and receiver, joint probability density function (PDF) of angle-of-departure and angle-of-arrival, as well as the joint PDF of time-of-arrival and angle-of-arrival are derived. Subsequently, the corresponding marginal PDFs are provided in a closed form. Thus, derived PDFs are suitable for any position of the base station, (base station placed inside or outside of scattering region). The proposed model is validated by several measured channels. The curve fitting results shown the high flexibility of the proposed model and outperforming results compared with several other geometric scattering models.

Software-Defined Networks (SDN) simplify tasks performed by the network switches and centralize the network management by clearly separating networking processes into an application, control, and data plane. An OpenFlow, the flagship of SDN implementation, has reduced the innovation of such networks by diminishing switching tasks to the simple lookup of packet flow tables. A novel hybrid architecture of a deeply programmable packet-switching node (DPPSN), based on field-programmable gate array (FPGA) and central processing unit (CPU) technologies, is proposed, with the aim of overcoming OpenFlow’s limitations regarding the ability to implement new protocols and advanced packet processing functionalities. It has been demonstrated, through the implementation and experimental evaluation of the DPPSN, that it is justified to use hybrid FPGA/CPU architecture for this purpose.

Although there are many attempts to engineer a domain specific language for the Internet of Things, most of them forget the fact that with the evolving of the Internet of Things, the end user will probably be a common person without an engineering or software development background. The designers of the UML had the same problem: how to make a language powerful enough for the professionals, but at the same time simple enough to be understood by a non-technical end user that gives the requirements. Inspired by this idea a Visual Domain Specific Modeling Language was developed for the IoT and proved that it is powerful enough for the professional and at the same time simple enough to be used by non-technical users.

With the goal of relieving the Internet of things (IoT)application designers of the complexities and heterogeneity of wireless sensory networks (WSNs), devices, communication media, protocols and operating systems, the development of higher level domain specific language has been undertaken. The result is DSL-4-IoT Editor-Designer, which is based on high level visual programming language, established on the class of visual domain specific modeling languages (VDSMLs). DSL-4-IoT is using formal presentations and abstract syntax in a metamodel. The visual front-end of the Editor has been developed in JavaScript language. The runtime execution of generated IoT application configuration files is done by the open source project “OpenHAB” runtime engine. In order to demonstrate the viability and usability of the developed DSL-4-IoT visual model based language, an experimental IoT testbed including 15 heterogeneous wireless sensory devices spanning two application domain (smart home and remote patient monitoring), has been designed and deployed.

In the design of MAC protocols for wireless sensor networks (WSN) it is necessary to fulfill some requirements such as low energy consumption, scalability, simplicity, etc. These requirements are not easy to fulfill from the viewpoint of implementation on FPGA or ASIC technologies. Therefore, in this paper we identify some challenges encountered during the design of MAC protocol for WSN. For some of these challenges, potential solutions are discussed. To illustrate the proposed solutions SMAC protocol is chosen. VHDL design of the S-MAC protocols is experimentally verified on the Altera EP2C5 FPGA development system.

In the process of design of protocols for medium access control in wireless sensor networks, it is necessary to find a compromise between energy saving, time sensitivity, scalability, adaptability and complexity. In this research, as an object of optimization S-MAC protocol is chosen. The main advantage of the S-MAC protocol is a state of sleep, which significantly reduces power consumption. Although the S-MAC protocol is described with a large number of parameters, in this paper we have selected three parameters that directly affect the time frame protocol: the duty cycle, the duration of the synchronization interval, and duration of the data interval. To assess the quality of the selected parameters, three measures were selected: total electricity consumption in the network, delay in the delivery of packets to the application layer, and the total achieved bandwidth. Using ns-2 network simulator, a model for testing the influence of parameters of S-MAC protocol on network performance has been developed. The parameters values are selected using the NSGA-II algorithm implemented in MATLAB software package, and the whole process of finding of non-dominated solution set is fully automated. In addition to multi-objective optimization of parameters, an experiment with single-objective optimization using aggregated utility function and the standard GA is performed. Finally, the analysis of the obtained set of non-dominated solutions is performed and a comparison with the results of the single-objective optimization is done.

In this paper, an algorithm for adaptation layer in order to improve fairness in bandwidth allocation among different traffic classes in IP/MPLS networks under heavy traffic load is proposed. A definition of the blocking frequency of traffic flows at the entry of autonomous network domain and proportional-priority coefficient per traffic class are proposed and used as the input parameters of the adaptation mechanism. In order to evaluate the validity of the proposed algorithm, proper simulation tool is needed and for these purposes OPNET Modeler 14.5 is extended with the modules for adaptation process. Development methodology for the design of modules for adaptation process within network simulators is also proposed. The simulation results proved the hypothesis that with a proper adaptation layer, improvement of the fairness of bandwidth allocation among different traffic classes under heavy network load and at the same time keeps the required QoS conditions in the preferred boundaries is possible.

The goal of this paper was to develop a Simple Access Object Protocol (SOAP) Parlay X Web service interface that supports standard GSM modems and can be used as development and testing environment for SMS based applications. The service interface was translated into Java classes from a selected set of Parlay X version 2.1 Web Service Description Language (WSDL) files providing mandatory SMS functionality. SendSms, ReceiveSms, NotificationManager and SmsNotification Web services were fully implemented. Other Parlay X services (e. g. MMS, ringtone services and other) can be built in a similar fashion and easily integrated into the system architecture. The service backend was implemented using Java wrapper classes that mimic the described Web services, their datatypes and membership functions. The SIM300 GSM modem was used to transmit and receive SMS, while a MySQL database schema was used as interface between the modem and the service interface. Handler classes (also implemented in Java) were used as modem behaviour controller, while the database connection was established using the Java Database Connectivity classes provided by Oracle. Detailed System architecture, implemented Web services functionality, database structure and Message Sequence Charts are given.

This paper presents an approach to the development of custom agents and their integration with network management systems. For the development of agents is given one approach, and according to this approach an implementation of the agent using Open Dynamic Management Kit (OpenDMK) libraries in the Java programming language is performed. Within the agents are implemented all standard Simple Network Management Protocol (SNMP) functionality - reading values, setting values and traps sending. Finally, the integration is performed with several network management systems such as Zenoss and Cacti. Tests have confirmed the success of this integration, thus verifying the proposed approach.

—In this paper, we propose an algorithm for adaptation layer in order to improve fairness in bandwidth allocation among different traffic classes in IP/MPLS networks under heavy traffic load. We propose a definition of the blocking frequency of traffic flows at the entry of autonomous network domain and proportional-priority coefficient per traffic class and use them as the input parameters of the adaptation mechanism. In order to evaluate the validity of the proposed algorithm, we need proper simulation tools and for that purposes we extend OPNET Modeler 14.5 with the modules for adaptation process. We also propose a development methodology for the design of modules for adaptation process within network simulators. The simulations results give us the proof of our hypothesis that with a proper adaptation layer we can improve the fairness of bandwidth allocation among different traffic classes under heavy network load and at the same time keep the required QoS conditions in the preferred boundaries.

This paper examines the possibility of MPLS-based network to perform adaptive routing based on traffic engineering and the possibilities of using the network simulator for testing network architectures that are capable of adaptive routing. The analysis of existing architectures and mechanisms for traffic engineering showed that the considered architecture shown stationarity and can not follow the dynamics of traffic in next generation networks. To improve the efficiency of utilization of allocated bandwidth, a solution is proposed in the area of dynamic adaptation structures. The analysis of scientific studies in this field, and documentation for the available network simulators found that there is currently no support for dynamic adaptation structures in the simulator. In order to achieve the development of adaptation structures independent of the type of adaptation layer and network simulator, a detailed methodology is proposed for the development of dynamic adaptation structures in network simulators. According to the proposed methodology, a successful implementation of an example adaptation layer is performed in the network simulator OPNET Modeler 14.5, which is confirmed by simulation results.