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In the Italian craft beer market, many small breweries and pubs propose a large number of products to beerlovers. In this highly fragmented market, it is hard for the beerlovers to assess the quality of a beer and it is hard for breweries and pubs to inform the beerlover of the quality of their offer. Supply chain tracking is an interesting tool to improve transparency of food markets. However, standard tracking approaches are challenging in highly fragmented contexts for several reasons. In this paper, we show how it is possible to realize a blockchain-based supply chain tracking tailored for the highly fragmented sector of the Italian craft beer. We collaborated with one of the players of that market to analyze the specific problems of that context and we report the results of this analysis. We show a design that addresses those problems and might be generalized to support tracking in other highly fragmented sectors. We estimate costs and that turn out to be affordable for that sector.

The Border Gateway Protocol (BGP) is the protocol that makes the various networks composing the Internet communicate to each other. Routers speaking BGP exchange updates to keep the routing up-to-date and allow such communication. This usually is done to reflect changes in the routing configurations or as a consequence of link failures. In the Internet as a whole it is normal that BGP updates are continuously exchanged, but for any specific IP prefix, these updates are supposed to be concentrated in a short time interval that is needed to react to a network change. On the contrary, in this paper we show that there are many IP prefixes involved in quite long sequences consisting of a large number of BGP updates. Namely, examining ∼30 billion updates collected by 172 observation points distributed worldwide, we estimate that almost 30% of them belong to sequences lasting more than one week. Such sequences involve 222285 distinct IP prefixes, approximately one fourth of the number of announced prefixes. We detect such sequences using a method based on the Discrete Wavelet Transform. We publish an online tool for the exploration and visualization of such sequences, which is open to the scientific community for further research. We group together sequences that exhibit common behaviours. For this purpose, we devise a clusterization algorithm able to group the sequences based on their similarity in time. We highlight four categories of clusters, which are attributable to different types of Internet events. Our online tool allows also to explore and to visualize the computed clusters.

Several data centers adopt fat-tree topologies, where high bisection bandwidth is achieved by interconnecting commodity hardware and by using specific routing solutions. These solutions, which include protocol implementations and configurations, are difficult to evaluate and test both for the density of fat-trees and for the complexity of the protocols. Also, since most issues show up only when a fault happens, it is unfeasible to perform such tests in a production environment. Additionally, the lack of standard testing procedures motivates an effort in developing solutions for such a critical task. In this paper, we propose a methodology devised for testing fat-tree routing protocol implementations. It adopts a wall-clock independent method to establish metrics, which permits normalizing the results of different routing protocol implementations independently from the execution environment. The methodology is implemented by Sibyl, a software framework developed to perform repeatable tests on arbitrary fat-tree topologies automatically. Sibyl also provides a set of tools to analyze the results and investigate implementation behaviors. We evaluate the methodology and Sibyl in three use cases. Such use cases witness a wide spectrum of situations where Sibyl is effective for analyzing, comparing, developing, and debugging routing protocol implementations.

The Border Gateway Protocol (BGP) is the protocol that makes the various networks composing the Internet communicate to each other. Routers speaking BGP exchange updates to keep the routing up-to-date and allow such communication. This usually is done to reflect changes in the routing configurations or as a consequence of link failures. In the Internet as a whole it is normal that BGP updates are continuously exchanged, but for any specific IP prefix, these updates are supposed to be concentrated in a short time interval that is needed to react to a network change. On the contrary, in this paper we show that there are many IP prefixes involved in quite long sequences consisting of a large number of BGP updates. Namely, examining \({\sim }30\) billion updates collected by 172 observation points distributed worldwide, we estimate that almost \(30\%\) of them belong to sequences lasting more than one week. Such sequences involve \(222\,285\) distinct IP prefixes, approximately one fourth of the number of announced prefixes. We detect such sequences using a method based on the Discrete Wavelet Transform. We publish an online tool for the exploration and visualization of such sequences, which is open to the scientific community for further research. We empirically validate the sequences and report the results in the same online resource. The analysis of the sequences shows that almost all the observation points are able to see a large amount of sequences, and that \(53\%\) of the sequences last at least two weeks.

We introduce an open-source, scalable, and distributed architecture, called Megalos, that supports the implementation of virtual network scenarios consisting of virtual devices (VDs) where each VD may have several Layer 2 interfaces assigned to virtual LANs. We rely on Docker containers to realize vendor-independent VDs and we leverage Kubernetes for the management of the nodes of a distributed cluster. Our architecture does not require platform-specific configurations and supports a seamless interconnection between the virtual environment and the physical one. Also, it guarantees the segregation of each virtual LAN traffic from the traffic of other LANs, from the cluster traffic, and from Internet traffic. Further, a packet is only sent to the cluster node containing the recipient VD. We produce several example applications where we emulate large network scenarios, with thousands of VDs and LANs. Finally, we experimentally show the scalability potential of Megalos by measuring the overhead of the distributed environment and of its signaling protocols.

We introduce an ETSI NFV compliant, scalable, and distributed architecture, called Megalos, that supports the implementation of virtual network scenarios consisting of virtual devices (VNFs) where each VNF may have several L2 interfaces assigned to virtual LANs. We rely on Docker containers to realize VNFs and we leverage Kubernetes for the management of the nodes of a distributed cluster. Our architecture guarantees the segregation of each virtual LAN traffic from the traffic of other LANs, from the cluster traffic, and from Internet traffic. Also, a packet is only sent to the cluster node containing the recipient VNF. The allocation of the VNFs to the nodes of the cluster is performed by Megalos Scheduler, taking into account the network topology in order to reduce the traffic among nodes. We produce an example application where we emulate a large network scenario, with thousands of VNFs and LANs, on a small cluster of 50 nodes. Finally, we experimentally show the scalability potential of Megalos by measuring the overhead of the distributed environment and of its signaling protocols.

La progettazione educativa è una pratica professionale complessa, che richiede di essere collocata non solo all’interno dei servizi in cui si esercita, ma anche nel contesto storico-sociale ed epistemologico cui i servizi appartengono e in cui gli educatori hanno sviluppato la loro professionalità. Il saggio evidenzia i modelli di progettazione presenti nei servizi e nelle attività educative, sottolineando l’esigenza di ridefinire pedagogicamente gli oggetti e il senso della progettazione educativa in particolare in uno scenario come quello attuale, che presenta una profonda crisi del milieu educativo. Quindi, il saggio propone di pensare la progettazione come “agire progettuale”, mostrandone le dimensioni metodologiche e l’articolazione pragmatica Educational planning is a complex professional practice that needs to be situated in both the working contexts and the broader historical, social and epistemological background to which services belong and where educators have developed their professionalism. The paper points out the common models of educational planning, highlighting the necessity to redefine from a pedagogical point of view the objects and the sense of it, within a scenario that is currently affected by a deep crisis of the “educational milieu”. Therefore, the paper suggests thinking the educational planning as “planning action”, and it shows its methodological dimensions and its pragmatic articulation.