Franco Callegati

On Combining Crowdsourcing, Sensing and Open Data for an Accessible Smart City

This work presents a novel geospatial mapping service, based on OpenStreetMap, which has been designed and developed in order to provide personalized path to users with special needs. This system gathers data related to barriers and facilities of the urban environment via crowd sourcing and sensing done by users. It also considers open data provided by bus operating companies to identify the actual accessibility feature and the real time of arrival at the stops of the buses. The resulting service supports citizens with reduced mobility (users with disabilities and/or elderly people) suggesting urban paths accessible to them and providing information related to travelling time, which are tailored to their abilities to move and to the bus arrival time. The manuscript demonstrates the effectiveness of the approach by means of a case study focusing on the differences between the solutions provided by our system and the ones computed by main stream geospatial mapping services.

Performance of Network Virtualization in cloud computing infrastructures: The OpenStack case

Cloud computing infrastructures will likely be a key component of future Internet architectures, owing to the many advantages of server and network virtualization, especially considering the emerging Network Function Virtualization and Software Defined Networking technologies. The cloud infrastructure will then determine the performance of the networking environment. In this paper, such issue is investigated with reference to OpenStack, a widely adopted cloud infrastructure management platform. In particular, the paper provides an insight on how OpenStack deals with multi-tenant network virtualization and evaluates the performance of its main network components by measuring packet throughput in an experimental test-bed.

Dynamic chaining of Virtual Network Functions in cloud-based edge networks

This manuscript investigates the issue of implementing chains of network functions in a “softwarized” environment where edge network middle-boxes are replaced by software appliances running in virtual machines within a data center. The primary goal is to show that this approach allows space and time diversity in service chaining, with a higher degree of dynamism and flexibility with respect to conventional hardware-based architectures. The manuscript describes implementation alternatives of the virtual function chaining in a SDN scenario, showing that both layer 2 and layer 3 approaches are functionally viable. A proof-of-concept implementation with the Mininet emulation platform is then presented to provide a practical example of the feasibility and degree of complexity of such approaches.

SDN for dynamic NFV deployment

This article reports a network functions virtualization proof of concept demonstrating the added value that dynamic software-defined networking control, coordinated with a flexible cloud management approach, brings to telco operators and service providers.

Live migration of virtual network functions in cloud-based edge networks

Emerging network paradigms, such as Software Defined Networking and Network Function Virtualization, represent the key enablers for efficient and cost-effective deployment and management of cloud-based edge networks, where a number of cooperating virtual machines can implement the tasks traditionally performed by expensive and disrupting network middleboxes. A key feature in such a scenario is the capability of live migrating a group of correlated virtual machines as a single entity representing a customers profile. Multiple VM live migration is a topic that has not been thoroughly studied in the literature. This manuscript presents a relatively simple model that can be used to derive some performance indicators, such as the whole service downtime and the total migration time, and allows to properly design the cloud-based edge network. The model is used to compare some simple scheduling strategies for the VM migration and to provide guidelines to such implementation.

CrowdSensing for smart mobility through a service-oriented architecture

Crowdsensing is a powerful approach to build representations of specific aspects of reality which are of interest for citizens in smart cities, and in particular for people with special needs. In this work, we present an application of the microservice paradigm to create a mobility services platform. By exposing each part of the process as a microservice, we achieve the ability of developing applications as orchestration of available components. Moreover, we leverage the possibility of sharing data between different applications in a controlled environment.

Performance of multi-tenant virtual networks in OpenStack-based cloud infrastructures

Future network architectures based on the emerging Network Function Virtualization and Software Defined Networking paradigms will significantly rely on cloud computing infrastructures, taking advantage of virtualization technologies. Performance of multi-tenant virtual networks will then be a key aspect to be considered when designing such cloud-based architectures. This issue is investigated in this paper with reference to the widely adopted OpenStack cloud infrastructure management platform. In particular, the paper provides an insight on how OpenStack deals with multi-tenant network virtualization and evaluates its performance in an experimental test-bed.

A Service-Oriented Approach to Crowdsensing for Accessible Smart Mobility Scenarios

This work presents an architecture to help designing and deploying smart mobility applications. The proposed solution builds on the experience already matured by the authors in different fields: crowdsourcing and sensing done by users to gather data related to urban barriers and facilities, computation of personalized paths for users with special needs, and integration of open data provided by bus companies to identify the actual accessibility features and estimate the real arrival time of vehicles at stops. In terms of functionality, the first “monolithic” prototype fulfilled the goal of composing the aforementioned pieces of information to support citizens with reduced mobility (users with disabilities and/or elderly people) in their urban movements. In this paper, we describe a service-oriented architecture that exploits the microservices orchestration paradigm to enable the creation of new services and to make the management of the various data sources easier and more effective. The proposed platform exposes standardized interfaces to access data, implements common services to manage metadata associated with them, such as trustworthiness and provenance, and provides an orchestration language to create complex services, naturally mapping their internal workflow to code. The manuscript demonstrates the effectiveness of the approach by means of some case studies.

Implementing dynamic chaining of Virtual Network Functions in OpenStack platform

Network Function Virtualization (NFV) is gaining a lot of interest as a flexible and cost-effective solution for replacing hardware-based, vendor-dependent middle-boxes with software-based appliances running in a cloud-like network environment. The NFV paradigm is then fundamental to bring the required programmatic capabilities to 5G transport networks. This paper discusses the practical issues of implementing dynamic chaining of virtual network functions running as virtual machines in the industry-standard OpenStack cloud platform. In particular, the focus is on the complexity of the underlying virtual network infrastructure and the design principles of a suitable SDN controller.

Virtual network function embedding in real cloud environments

Future network architectures will be completely reshaped by the emerging Network Function Virtualization (NFV) paradigm, and telco operators will likely deploy flexible infrastructures based on the cloud, offering programmable connectivity services and computing/storage facilities in the form of Virtual Data Centers (VDCs). This paper introduces and discusses some challenging technical issues associated with this promising approach, with a special focus on the exploitation of industry-relevant cloud platforms, such as OpenStack, and on network-aware optimal placement problem of entire VDCs, taking into account multiple virtual (Virtual Machines - VMs, virtual networks, ?) and physical (host capacities, network topology and capacity, ?) resources and constraints. The proposed placement, computed for real production OpenStack deployments, not only satisfies the predicted communication for all VDCs deployed atop the same physical data center, but also accounts for the (real) computing overhead due to intense communication load of VMs co-located on the same physical host, such as in the case of Virtual Network Functions (VNF) embedding, typically neglected by similar existing works.