Internet and communication technologies have lowered the costs to collaborate for communities, leading to new services like user-generated content and social computing and, through collaboration, collectively built infrastructures, such as community networks. Community networks are formed when individuals and local organisations from a geographic area team up to create and run a community-owned IP network to satisfy the community's demand for ICT. Internet access is often considered the main service of community networks, but the provision of services of local interest within the network is a unique opportunity for community networks, which is currently predominantly unexplored. The consolidation of today's cloud technologies offers community networks the possibility to collectively build community clouds, building upon user-provided networks, and extending towards an ecosystem of cloud services. We propose a framework for building a collaborative distributed community cloud system that employs resources contributed by the members of the community network for provisioning infrastructure and software services. This framework is tailored to the specific social, economic, and technical characteristics of community networks and requirements for community clouds in order to be successful and sustainable. We materialise this framework in the implementation of the Cloudy distribution. We conduct real deployments of these clouds in the Guifi.net community network and evaluate cloud-based applications such as service discovery and distributed storage. This deployment experience supports the feasibility of community clouds and our measurements demonstrate the performance of services and applications running in these community clouds. Our results encourage the development and operation of collaborative cloud-based services using the resources of a community network. We anticipate that such services can effectively complement commercial offers and have the potential to boost innovation in application areas in which end-user involvement is required.

LoRa has emerged in recent years as a wireless technology providing long-range communication for-low power Internet of Things (IoT) devices. The LoRaWAN architecture adds the Medium Access Control (MAC) and application layers and defines a star of stars topology suitable for many and diverse IoT applications. However, in a number of scenarios, a more flexible network topology than LoRaWAN's is needed. We review the state of the art of the design and implementation of multihop and mesh solutions for LoRa and LoRaWAN. We discuss the remaining challenges for multi-hop and mesh solutions to overcome in order to unlock the opportunities that decentralized, self-organizing and infrastructure-less LoRa networks can bring to IoT applications.

High-speed, submicrosecond-latency, largeport-count (thousands) optical packet switches (OPSs) for intercluster communication networks can become a key element in the deployment of cloud-oriented largescale data centers. In this work we numerically investigate the performance of a large-port-count wavelength-division multiplexing (WDM) OPS based on a Spanke-type architecture with highly distributed control. We analyze it under a data center traffic model to determine its suitability for this type of environment. Results indicate that the proposed architecture can be scaled to 4096 ports while providing packet loss below 10 −6 and latency under 1 μs, with a total switching capacity over 55 Tbits∕s. Additionally, we propose and analyze two WDM OPS architectures. The first one detects and processes small and large-sized Ethernet packets with two parallel switches. The second architecture includes multiple receivers to decrease packet losses and latency while using very limited electronic buffers. Results indicate that both techniques can lead to substantial improvements. In terms of packet loss and latency, they allow up to 40% higher input load with respect to the original WDM OPS architecture.

The response conducted by emergency units after natural disasters, such as earthquakes, has to be coordinated, fast, and efficient in order to rescue and care for the victims, keeping all the population-and the units themselves-safe amidst the usual chaos. Outages in wireless networks, as well as fiber-or copper-based landline and Internet connections, are to be expected in these situations, so alternative communication solutions must be considered. To contribute in this duty, we propose a communication system that uses the LoRaWAN architecture to allow citizens to report their status to emergency units and public authorities with simple messages and interaction mechanisms. The purpose of this system is to keep people and first responders connected, and thus improve the capability to coordinate the evacuation activities. To analyze the system performance and capabilities, we model a district of Coquimbo, a harbor town in Chile that houses approximately 28,000 people in 7500 homes, and simulate it with a baseline configuration. We explore several settings for the system in order to determine its characteristics and limitations, to better understand its scalability and portability to other environments, and to outline the remaining challenges to make the system attain specific performance guarantees.