Deploying service functions, SFs, is an essential action for a network provider. However, the action of creating, modifying and removing network SFs is traditionally very costly in time and effort, requiring the acquisition and placement of specialized hardware devices and their interconnection. Fortunately, the emergence of concepts like cloud computing, SDN, and ultimately NFV is expected to raise new possibilities for the management of SFs with a positive impact in terms of agility and cost. From a telco viewpoint these concepts can help to both reduce OPEX and open the door to new business opportunities. In this article, we identify how téleos can benefit from the abovementioned paradigms, and explore some of the aspects that still need to be addressed in the NFV domain. We focus on two major aspects: enabling telco infrastructures to adopt this new paradigm, and orchestrating and managing SFs toward telco-ready cloud infrastructures. The technologies we describe enable a telco to deploy and manage SFs in a distributed cloud infrastructure. In this context, the Cloud4NFV platform is presented. Special attention is given to the way SFs are modeled toward cloud infrastructure resources. In addition, we explore the ability to perform service function chaining as one of the fundamental features in the composition of SFs. Finally, we describe a proof of concept that demonstrates how a telco can benefit from the described technologies.

The advances on recent communication paradigms brings new security and privacy challenges, mainly about personal data collection by smart devices. Resource constrained devices face serious issues to run complex cryptographic algorithms. Trying to evaluate the performance impact of those algorithms in usual and common devices used in smart homes, in this paper we tested the impact of different cryptographic algorithms in low computational devices, typically used in smart devices applied in smart homes, testing different security configurations and using the two most used transport protocols (HTTP and MQTT). The experiment measures their effects on six commonly used embedded devices in IoT WSNs: ESP8622, ESP32, and Raspberry Pi (RPi) from 1 to 4. The experiment measured the power consumption, message delay, and additional message length (bytes). Moreover, the analysis was also used to model security algorithms. The experimental results from long runs (72 hours) reveal the cryptographic solution choice is significant for the message delay and additional message length.

Low Power Wide Area Networks (LPWANs) are becoming the most suitable communication technologies in the Internet of Things (IoT) applications due to their low power consumption, long communication range and low cost. Currently, Long Range Wide Area Network (LoRaWAN) is one of the most popular LPWANs. Because it offers the possibility to build private networks with an open standard, LoRaWAN is the most deployed LPWAN solution. However, LoRaWAN supports only one-hop communication, that is, the end-devices are connected directly to the gateways. Since LoRa links can be kilometers long, its signals may undergo interference with other radio signals or encounter obstacles such as buildings, trees. In urban areas, to ensure that indoor LoRa devices can successfully transfer data back to remote gateways (GWs), a dense deployment of GWs is required. Unfortunately, the deployment of many GWs increases the network cost. Multi-hop communication can be exploited to increase LoRaWAN network coverage and packet delivery ratio (PDR) without deploying additional GWs. Therefore, in order to improve LoRaWAN performance, different routing approaches have been recently proposed aiming to create LoRaWAN multi-hop networks where some devices can play the role of relay nodes. However, in some use cases like Smart Water Grid (SWG), where nodes are buried underground inside the pipelines, the use of some SWG devices as relay nodes is not efficient in terms of energy consumption. In this paper, we first provide an in-depth survey on different routing protocols proposed for LoRaWAN multi-hop networks followed by a useful comparison between these approaches. Then, to enable efficient peer-2-peer (P2P) communication between end-devices in SWG, we propose a routing protocol based on Software Defined Networking (SDN) where some specific nodes called Relay Nodes (RNs) relay data from leakages detection nodes. In the case where a sensor detects a leak, a signal is sent to shut off the water valve automatically through our routing approach. Through simulations under LoRaSim, our proposed solution outperforms the standard single-hop network in terms of energy consumption and packet error rate. A range of issues, problems are provided and some research directions are suggested.

Network operators are under pressure to offer efficient network-based services while keeping service deployment costs to a minimum. Network Functions Virtualization (NFV) can potentially revolutionize network-based services bringing low deployment costs for network operators. NFV has been introduced to ultimately extend the non-proprietary and open-standardbased model to network and service deployments, significant improvements to today’s proprietary locked implementations. Notwithstanding the continuous efforts of both academia and industry to support the NFV paradigm, the current NFV solutions offered are still in its infancy. In this survey, we provide a detailed background of NFV to establish a comprehensive understanding of the subject, ranging from the basics to more advanced topics. Moreover, we offer a comprehensive overview of the NFV main concepts, standardization efforts, benefits of NFV and discuss the NFV architecture as defined by the European Telecommunications Standardization Institute (ETSI). Furthermore, we discuss NFV applicability and current open source projects. We then highlight NFV requirements, design considerations, and developmental architectural impairments and barriers to commercial NFV deployments. Finally, we conclude enumerating future directions for NFV development.

Fault-tolerance is an essential aspect of network resilience. Fault-tolerance mechanisms are required to ensure high availability and high reliability in systems. The advent of software-defined networking (SDN) has both presented new challenges and opened new paths to develop novel strategies, architectures, and standards to support fault-tolerance. In this survey, we address SDN fault-tolerance and discuss the OpenFlow fault-tolerance support for failure recovery. We highlight the mechanism used for failure recovery in Carrier-grade networks that includes detection and recovery phases. Furthermore, we highlight SDN-specific fault-tolerance issues and provide a comprehensive overview of the state-of-the-art SDN fault-tolerance research efforts. We then discuss and structure SDN fault-tolerance research according to three distinct SDN planes (i.e., data, control, and application). Finally, we conclude enumerating future research directions for SDN fault-tolerance development.

Fault-tolerance methods are required to ensure high availability and high reliability in cloud computing environments. In this survey, we address fault-tolerance in the scope of cloud computing. Recently, cloud computing-based environments have presented new challenges to support fault-tolerance and opened new paths to develop novel strategies, architectures, and standards. We provide a detailed background of cloud computing to establish a comprehensive understanding of the subject, from basic to advanced. We then highlight fault-tolerance components and system-level metrics and identify the needs and applications of fault-tolerance in cloud computing. Furthermore, we discuss state-of-the-art proactive and reactive approaches to cloud computing fault-tolerance. We further structure and discuss current research efforts on cloud computing fault-tolerance architectures and frameworks. Finally, we conclude by enumerating future research directions specific to cloud computing fault-tolerance development.