Wired/Wireless Internet Communications

In Industry 4.0 scenarios, novel applications are enabled by the capability to gather large amount of data from pervasive sensors and to process them in order to devise the “digital twin” of a physical equipment. The heterogeneity of hardware sensors, communication protocols and data formats constitutes one of the main challenge toward the large-scale adoption of the Internet of Things (IoT) paradigm on industrial environments. To this purpose, the W3C Web of Things (WoT) group is working on the definition of some reference standards intended to describe in a uniform way the software interfaces of IoT devices and services, and hence to achieve the full interoperability among different IoT components regardless of their implementation. At the same time, due also to the recent appearance of the WoT W3C draft, few testbed and real-world deployments of the W3C WoT architecture has been proposed so far in the literature. In this paper, we attempt to fill such gap by describing the realization of a WoT monitoring application of a generic indoor production site: the system is able to orchestrate the sensing operations from three heterogeneous Wireless Sensor Networks (WSNs). We describe how the components of the W3C WoT architecture have been instantiated in our scenario. Moreover, we demonstrate the possibility to decouple the mash-up policies from the network functionalities, and we evaluate the overhead introduced by the WoT approach.

Several Internet of Things (IoT) applications have strict performance requirements, in terms of reliability and power consumption. IEEE 802.15.4 Time Slotted Channel Hopping (TSCH) is a recently standardised Medium Access Control (MAC) protocol that supports these requirements by keeping the nodes time-synchronised. In order to ensure successful communication between a sender and a receiver, the latter starts listening shortly before the expected frame’s arrival. This time offset is called guard time and it aims to reduce the probability of missed frames due to clock drift. This paper investigates the impact of the guard time on the energy consumption and proposes a scheme for the decentralised adaptation of the guard time in each node depending on its hop-distance from the sink. Simulations and test-bed experiments demonstrate that guard time adaptation can reduce the energy consumption by up to 50%, without compromising the reliability of the network.

Internet of Things (IoT) products became recently an essential part of any home in conjunction with the great advancements in internet speeds and services. The invention of IoT based devices became an easy task that could be performed through the widely available IoT development boards. Raspberry Pi is considered one of the advanced development boards that have high hardware capabilities with a reasonable price. Unfortunately, the security aspect of such products is overlooked by the developers, revealing a huge amount of threats that result in invading the privacy and the security of the users. In this research, we directed our study to SSH due to its extensive adoption by the developers. It was found that due to the nature of the Raspberry Pi and development boards, the Raspberry Pi generates predictable and weak keys which make it easy to be utilized by MiTM attack. In this paper, Man in The Middle (MiTM) attack was conducted to examine the security of different variations provided by the SSH service, and various hardening approaches were proposed to resolve the issue of SSH weak implementation and weak keys.

IEEE 802.11 network deployments are ubiquitous and provide connectivity to millions of users. Interference that originates from other technologies, like simple Radio Frequency (RF) equipment, severely degrades the performance of those networks. To effectively manage wireless networks, the interference needs to be modeled and predicted. The current state of the art models are insufficient to model performance correctly. In this letter, we describe the interference as an interrupted Poisson process and use a decomposition approach to predict the latency of an interfered client from the latency of a non-interfered client. This novel approach allows for fast and easy prediction of latency in an interfered network. The results show that our method gets as close as 6% of the real value.

Named-Data Networking (NDN) is a potential Future Internet Architectures which introduces a shift from the existing host-centric IP-based Internet infrastructure towards a content-oriented one. Its design, however, can be misused to introduce a new type of DoS attack, better known as Interest Flooding Attack (IFA). In IFA, an adversary issues non-satisfiable requests in the network to saturate the Pending Interest Table(s) (PIT) of NDN routers and prevent them from properly handling the legitimate traffic. Prior solutions to mitigate this problem are not highly effective, damages the legitimate traffic, and incurs high communication overhead.

In this paper, we propose a novel mechanism for IFA detection and mitigation, aimed at reducing the memory consumption of the PIT by effectively reducing the malicious traffic that passes through each NDN router. In particular, our protocol exploits an effective management strategy on the PIT which differentially penalizes the malicious traffic by dropping both the inbound and already stored malicious traffic from the PIT. We implemented our proposed protocol on the open-source ndnSIM simulator and compared its effectiveness with the one achieved by the existing state-of-the-art. The results show that our proposed protocol effectively reduces the IFA damages, especially on the legitimate traffic, with improvements that go from 5% till 40% with respect to the existing state-of-the-art.

Various applications used by mobile users today need seamless connectivity for providing a good quality user experience. Enterprise Wireless Local Area Network (WLAN) is one of the technologies used by mobile devices to connect to the Internet in several environments. For providing seamless connectivity and communication, mobility management becomes an important aspect of such deployments. In this paper, we propose a client-unaware handover process for NAT (Network Address Translation) operation mode of the access points in a Software Defined Networking (SDN) based enterprise WLAN framework. The proposed mechanism has been implemented in simulation and the results show that the proposed mobility management mechanism is able to achieve seamless handover and provide uninterrupted connectivity and communication to the mobile devices.

The success of a UAV mission depends on communication between a GCS (Ground Control Station) and a group of UAVs. It is essential that the freshness of the commands received by UAVs is maintained as mission parameters often change during an operation. Ensuring the freshness of the commands received by UAVs becomes more challenging when operating in an adversarial environment, where the communication can be impacted by interference. We model this problem as a game between a transmitter (GCS) equipped with directed antennas, whose task is to control a group of UAVs to perform a mission in a protected zone, and an interferer which is a source spherically propagated jamming signal. A fixed point algorithm to find the equilibrium is derived, and closed form solutions are obtained for boundary cases of the resource parameters.

Because of developments in society and technology, new services and use cases have emerged, such as vehicle-to-everything communication and smart manufacturing. Some of these services have stringent requirements in terms of reliability, bandwidth, and network response time and to meet them, deploying network functions (NFs) closer to users is necessary. Doing so will lead to an increase in costs and the number of NFs. Under such circumstances, the use of optimization strategies for the placement of NFs is crucial to offer Quality of Service (QoS) in a cost-effective manner. In this vein, this paper addresses the User Plane Functions Placement (UPFP) problem in 5G networks. The UPFP is modeled as a Mixed-Integer Linear Programming (MILP) problem aimed at determining the optimal number and location of User Plane Functions (UPFs). Two optimization models are proposed that considered various parameters, such as latency, reliability and user mobility. To evaluate their performance, two services under the Ultra-Reliable and Low-Latency Communication (URLLC) category were selected. The acquired results showcase the effectiveness of our solutions.

The future 5G New Radio (NR) systems are expected to support both multicast and unicast traffic. However, these traffic types require principally different NR system parameters. Particularly, the area covered by a single antenna configuration needs to be maximized when serving multicast traffic to efficiently use system resources. This prevents the system from using the maximum allowed number of antenna elements decreasing the inter-site distance between NR base stations. In this paper, we formulate a model of NR system with multi-connectivity capability serving a mixture of unicast and multicast traffic types. We show that multi-connectivity enables a trade-off between new and ongoing session drop probabilities for both unicast and multicast traffic types. Furthermore, supporting just two simultaneously active links allows to exploit most of the gains and the value of adding additional links is negligible. We also show that the service specifics implicitly prioritize multicast sessions over unicast ones. If one needs to achieve a balance between unicast and multicast session drop probabilities, explicit prioritization mechanism is needed at NR base stations.

Due to growing throughput demands dictated by innovative media applications (e.g., \(360^\circ \) video streaming, augmented and virtual reality), millimeter-wave (mmWave) wireless access is considered to be a promising technology enabler for the emerging mobile networks. One of the crucial usages for such systems is indoor public protection and disaster relief (PPDR) missions, which may greatly benefit from higher mmWave bandwidths. In this paper, we assess the performance of on-demand mmWave mesh topologies in indoor environments. The evaluation was conducted by utilizing our system-level simulation framework based on a realistic floor layout under dynamic blockage conditions, 3GPP propagation model, mobile nodes, and multi-connectivity operation. Our numerical results revealed that the use of multi-connectivity capabilities in indoor deployments allows for generally improved connectivity performance whereas the associated per-node throughput growth is marginal. The latter is due to the blockage-rich environment, which is typical for indoor layouts as it distinguishes these from outdoor cases. Furthermore, the number of simultaneously supported links at each node that is required to enhance the system performance is greater than two, thus imposing considerable control overheads.

5G and Beyond 5G networks are calling for advanced networking schemes that can efficiently contribute to deal with the foreseen increase of the mobile data traffic, which inherently brings along an increase of the energy consumed by mobile nodes to support it. The non-real-time nature of an important share of that traffic makes it possible to use opportunistic networking mechanisms in cellular networks that can exploit the traffic’s delay-tolerance to find efficient transmission conditions. In this context, this paper proposes an scheduling and mode selection scheme that integrates opportunistic Device-to-Device (D2D) networking mechanisms in cellular networks to reduce the energy consumption for non-real-time traffic. The proposed scheme utilizes a probabilistic model that exploits context information available in cellular networks to obtain an a-priori estimate of the energy cost for transmitting the different fragments of a content using any of the following modes: single-hop traditional, opportunistic cellular and opportunistic D2D-aided cellular. Based on these estimates, the proposed scheme selects the communication mode for each fragment, and schedules the time instant at which the transmission should take place. Our performance evaluation shows that the proposed scheme results in up to 90% energy consumption reduction, compared to traditional single-hop cellular communications, and performs closely to an optimal scheme which assumes full knowledge of network conditions and nodes’ trajectories.

Novel interactive applications require small end-to-end latency for providing end users with good Quality of Experience. To prevent the bufferbloat problem causing increased delay, various AQM solutions have recently emerged. One of the most widely adopted method is called CoDel that detects the increased delay by maintaining the per packet sojourn times and compering them to a desired target delay. Accordingly, congestion situation is indicated when the sojourn time exceeds the target delay. CoDel applies a drop-based feedback to notify the responsive sources about congestion only when the deviation from the target delay is permanent. Dropping packets is then compensated by packet re-transmissions in case of TCP which worsens utilization. In this paper, we propose an ECN-enhanced CoDel that distinguishes between low and high levels of congestion, and ECN-marks or drops the packets, respectively. The performance of the proposed method is analyzed in thorough NS-3 simulations with variable number of flows. The proposed ECN-marking reduces the number of packets re-transmissions and provides similarly good characteristics including convergence time and fairness to the original drop-based CoDel.

Designing performance-enhanced and large-scale overlay networks over the conventional IP substrate encounters different implementation obstacles put in place by Internet Service Providers (ISPs). These include lack of proper privileges and restrictive routing policies that prevent the overlay services from being deployed easily. The evolution of Software Defined Networks (SDNs), however, helps to address these concerns by simplifying the mechanism for overlay router design. In this paper, we have included an analysis of 18,906 delay traces from a network of 138 hosts. Our main aim was to demonstrate the rich existence of IP overlay paths that can be leveraged to significantly enhance Internet routing performance. We try to make the case for using layer-3 forwarding minimum delay overlay paths by demonstrating superior performance in this approach compared to existing overlay designs which work mostly at the TCP and application layers. In particular, the study was conducted to benefit applications that are sensitive to end-to-end delay and throughput. This paper presents a specific analysis of end-to-end delay in order to enhance TCP performance. The current work aims at increasing throughput and reducing file transfer time via overlay while maintaining simplicity and preserving all TCP characteristics. The results of this study show that the use of the shortest delay paths between physically disjoint node pairs can benefit TCP throughput and minimize file transfer time by orders of magnitude. The ultimate objective behind this study is to develop a reliable and scalable over-lay design for file transfers that require high transmission rates.

Device-to-device (D2D) communications and cellular solutions represent key technologies for the development of a future infrastructure in which fifth-generation (5G) systems and the Internet of Things (IoT) will converge. A tricky issue to be carefully investigated in D2D communications is the prevention of threats to privacy and security caused by malicious devices. Thus, security mechanisms must be implemented in order to assure a reliable data exchange among involved devices. In this paper, we propose MtMS-sD2D (Machine-type Multicast Service with secure D2D), an architecture for the delivery of multicast traffic in an IoT scenario that takes advantage from D2D communications made reliable by means of a security mechanism. Furthermore, we discuss the procedures that must be followed to efficiently deliver multicast traffic. Finally, we provide some preliminary yet insightful simulation results .

In this research, we leverage the emerging concept of network slicing to enable the end-to-end integrated Information-Centric Networking (ICN) and Content Delivery Network (CDN) for 5G networking infrastructure. While CDN is deployed to cache content at the optimal server corresponding to the content and geographical location, this paper focuses on verifying the efficiency of ICN slice for regional content distribution. Specifically, the ICN slice can be established by the regional Orchestrator by following the current NFV/SDN standard. Then, the slice stitching process will be performed to interconnect two slices after their establishments via the Orchestrator. We also implement an OpenStack-based virtual node which supports both IP and ICN protocols and acts as the ICN-Gateway. The joint-testbed evaluations conducted between Japan side (ICN slice) and Europe side (CDN slice) show that the deployment of ICN Gateway and the proposed Node ID-based ICN naming structure can improve network performance and avoid network congestion.

This paper presents a new video delivery scheme in mobile networks using Multi-Access Edge Computing (MEC). Our goal is to improve the quality of video streaming experienced by the mobile video consumer. Our approach is based upon Dynamic Adaptive Streaming over HTTP. We present a novel algorithm, which uses information obtained from the Radio Network Information Service of MEC to provide the mobile user with a video quality matching the current radio link quality and channel capacity. We evaluate our approach using a real experiment performed on a Long Term Evolution (LTE) femto cell test-bed. Our algorithm displays enhanced adaptation of video rates in comparison to other state of the art solutions.

Distributed control applications are considered where the control functions are implemented by software of a centralized controller and where system state information and control commands are communicated through a shared communication infrastructure. Through the shared communication infrastructure the control functionalities of the individual control loops may influence each other and can have an affect on Service Level Objectives (SLO) to be guaranteed for each individual control application. In this contribution a novel approach is suggested for an enhanced CSMA/CD local area network infrastructure where the application control layer is directly put on an enhanced Media Access Control (MAC) layer of the communication infrastructure to minimize control delays. A comprehensive model is derived for the resulting network with all competing applications and protocol functions for safe communications. The performance of the MAC layer request is analyzed exactly by a stochastic phase T_C representing its aggregated behavior. The delay performance of the individual control applications is analyzed by means of a queuing model of type GI/G/1 where GI represents the total control request arrival process and G a virtual service time T_C from which the aggregated network delay parameters are derived. The distributed network control system (NCS) model with the shared infrastructure is analyzed exactly by methods of Control Theory by computational algorithms and MATLAB Simulink tool support.

The authors investigate a network emulator performance versus the variability of hardware/software features of the hosting machine. In particular, the evaluation of static and dynamic delays is carried out considering several testing conditions. In detail, as concerns emulator configurations, the influence of packet rates on imposed delays values and distributions are analyzed; as for hardware and software, different values for RAM, CPU cores and operating system are tested. Results, reported as mean values and standard deviation, show two main trends: the resource availability has an important impact on the emulation stability and on the measurement repeatability; secondly, higher differences in performance levels for low imposed delay values, which is the most interesting zone in a few milliseconds latency world. The paper aims to show that the capability to emulate network impairments is generally influenced by hardware/software capabilities and it must be considered when using network emulation for specific test purposes.

We address the problem of devising an optimized energy aware flight plan for multiple Unmanned Aerial Vehicles (UAVs) mounted Base Stations (BS) within heterogeneous networks. The chosen approach makes use of Q-learning algorithms, through the definition of a reward related to relevant quality and battery consumption metrics, providing also service overlapping avoidance between UAVs, that is two or more UAVs serving the same cluster area. Numerical simulations and different training show the effectiveness of the devised flight paths in improving the general quality of the heterogeneous network users.