Giacomo Verticale | Politecnico di Milano (original) (raw)

Papers by Giacomo Verticale

The explosion of mobile multimedia and Internet-of-things (IoT) services implies strong requireme... more The explosion of mobile multimedia and Internet-of-things (IoT) services implies strong requirements for seamless switching among various types of networks. Thus, to offer true ubiquitous Internet connection, a Fixed and Mobile Converged (FMC) network architecture is essential for the future 5G network. Such a convergent network can not only improve the utilization of network resources, but also inspire new add-on services for FMC network operators. In this paper, we introduce a shared caching overlay based on Information Centric Networking (ICN). It is deployed on top of the FMC network and controlled by the FMC network operator to offer Caching as a Service (CaaS) to Over-The-Top (OTT) service providers and virtual network operators. Business analysis and performance evaluation will highlight the benefits of deploying such a controlled Shared Caching System (SCS) over an FMC network.

2015 International Conference and Workshops on Networked Systems (NetSys), 2015

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2013

Procedia Computer Science, 2014

ABSTRACT Distributed Hash Table-based overlays are widely used to support efficient information r... more ABSTRACT Distributed Hash Table-based overlays are widely used to support efficient information routing and storage in structured peer- to-peer networks, but they are also subject to numerous attacks aimed at disrupting their correct functioning. In this paper we analyze the impact of the Eclipse attack on a Chord-based overlay in terms of number of key lookups intercepted by a collusion of malicious nodes. Moreover, we propose some modifications to the Chord routing protocol in order to mitigate its effects. Such countermeasures can operate in a distributed fashion or assume the presence of a centralized trusted entity and introduce a limited traffic overhead. The effectiveness of the proposed mitigation techniques has been shown through numerical results.

2013 IEEE International Conference on Smart Grid Communications (SmartGridComm), 2013

ABSTRACT The massive integration of renewable energy sources into the power grid ecosystem with t... more ABSTRACT The massive integration of renewable energy sources into the power grid ecosystem with the aim of reducing carbon emissions must cope with their intrinsically intermittent and unpredictable nature. Therefore, the grid must improve its capability of controlling the energy demand by adapting the power consumption curve to match the trend of green energy generation. This could be done by scheduling the activities of deferrable electrical appliances. However, communicating the users' needs about the usage of the electrical appliances leaks sensitive information about habits and lifestyles of the customers, thus arising privacy concerns. This paper proposes a privacy-preserving framework to allow the coordination of energy consumption without compromising the privacy of the users: the service requests generated by the domestic appliances are diveded in crypto-shares using Shamir Secret Sharing scheme and collected through an anonymous routing protocol based on Crowds by a set of schedulers, which schedule the requests operating directly on the shares. We discuss the security guarantees provided by our proposed infrastructure and evaluate its performance, comparing it with the optimal scheduling obtained through an Integer Linear Programming formulation.

Computer Communications, 2012

ABSTRACT The Next Generation Network (NGN) will enable service providers to offer broadband servi... more ABSTRACT The Next Generation Network (NGN) will enable service providers to offer broadband services with differentiated quality to their subscribers. In this way, the providers will be able to satisfy and retain the critical segment of the top-demanding customers, who generate the largest share of the provider's revenues. However, service pricing is as important as service quality. In order to offer competitive prices, bilateral per service negotiation between the customer and the supplier is an interesting practical solution that can provide better results than rigid offers based on fixed price-rate lists. In the application scenario of Broadband Wireless Access, the supplier can adapt its offer of wireless access bandwidth to the dynamics of customer-generated traffic, giving more bandwidth per session when traffic is low and less bandwidth per session when traffic is high. We present and study the performance of an algorithm for automatic service level pricing in which two agents negotiate over the service transmission rate and the price on behalf of the user and of the provider. The performance of the proposed negotiation scheme is evaluated with simulations. The paper also compares our algorithm to the fixed-price scheme and to an auction-based strategy based on the Vickrey scheme.

The widespread deployment of Automatic Metering Infrastructures in Smart Grid scenarios rises gre... more The widespread deployment of Automatic Metering Infrastructures in Smart Grid scenarios rises great concerns about privacy preservation of user-related data, from which detailed information about customer's habits and behaviors can be deduced. Therefore, the users' individual measurements should be aggregated before being provided to External Entities such as utilities, grid managers and third parties. This paper proposes a security architecture for distributed aggregation of additive data, in particular energy consumption metering data, relying on Gateways placed at the customers' premises, which collect the data generated by local Meters and provide communication and cryptographic capabilities. The Gateways communicate with one another and with the External Entities by means of a public data network. We propose a secure communication protocol aimed at preventing Gateways and External Entities from inferring information about individual data, in which privacy-preserving aggregation is performed by means of a cryptographic homomorphic scheme. The routing of information flows can be centralized or it can be performed in a distributed fashion using a protocol inspired by Chord. We compare the performance of both approaches to the optimal solution minimizing the data aggregation delay.

Demand Side Management (DSM) makes it possible to adjust the load experienced by the power grid w... more Demand Side Management (DSM) makes it possible to adjust the load experienced by the power grid while reducing the consumers’ bill. Game-theoretic DSM is an appealing decentralized approach for collaboratively scheduling the usage
of domestic electrical appliances within a set of households while meeting the users’ preferences about the usage time. The drawback of distributed DSM protocols is that they require each
user to communicate his/her own energy consumption patterns, which may leak sensitive information regarding private habits.
This paper proposes a distributed Privacy-Friendly DSM system
that preserves users’ privacy by integrating data aggregation and perturbation techniques: users decide their schedule according to aggregated consumption measurements perturbed by means of Additive White Gaussian Noise (AWGN). We evaluate the noise power and the number of users required to achieve a given privacy level, quantified by means of the increase of the information entropy of the aggregated energy consumption pattern. The performance of our proposed DSM system is compared to the one of a benchmark system that does not support privacy preservation in terms of total bill, peak demand and convergence time. Results show that privacy can be improved at the cost of increasing the peak demand and the number of game iterations, whereas the total bill is only marginally incremented.

The success of novel bandwidth-consuming multimedia services such as Video-on-Demand (VoD) is lea... more The success of novel bandwidth-consuming multimedia
services such as Video-on-Demand (VoD) is leading to
a tremendous growth of the Internet traffic. Content caching
can help to mitigate such uncontrolled growth by storing video content closer to the users in core, metro and access network nodes. So far, metro and especially access networks supporting mobile and fixed users have evolved independently, leveraging logically (and often also physically) separate infrastructures; this means that mobile users cannot access caches placed in the fixed access network (and vice-versa), even if they are geographically close to them, and energy consumption implications of such undesired effect must be investigated. We define an optimization problem modeling an energy-efficient placement of caches in core, metro and fixed/mobile access nodes of the network. Then, we show how the evolution towards a Fixed-Mobile Converged metro/access network, where fixed and mobile users can share caches, can reduce the energy consumed for VoD content delivery.

The Network Functions Virtualization (NFV) paradigm is the most promising technique to help netwo... more The Network Functions Virtualization (NFV) paradigm is the most promising technique to help network providers in the reduction of capital and energy costs. The deployment of virtual network functions (VNFs) running on generic x86 hardware allows higher flexibility than the classical middleboxes approach. NFV also reduces the complexity in the
deployment of network services through the concept of service
chaining, which defines how multiple VNFs can be chained
together to provide a specific service. As a drawback, hosting
multiple VNFs in the same hardware can lead to scalability issues, especially in the processing-resource sharing. In this paper, we evaluate the impact of two different types of costs that must be taken into account when multiple chained VNFs share the same processing resources: the upscaling costs and the context switching costs. Upscaling costs are incurred by VNFs multicore implementations, since they suffer a penalty due to the needs of load balancing among cores. Context switching costs arise when multiple VNFs share the same CPU and thus require the loading/saving of their context. We model through an ILP problem the evaluation of such costs and we show their impact in a VNFs consolidation scenario, when the x86 hardware deployed in the network is minimized.

Internet traffic is increasingly becoming a mediastreaming traffic. Especially, Video-on-Demand (... more Internet traffic is increasingly becoming a mediastreaming
traffic. Especially, Video-on-Demand (VoD) services
are pushing the demand for broadband connectivity to the
Internet, and optical fiber technology is being deployed in the
access network to keep up with such increasing demand. To
provide a more scalable network architecture for video/content
delivery, network operators are currently considering novel
integrated metro/access networks which accommodate replicated
video servers directly in their infrastructure. In such way, servers
for VoD delivery are placed nearer to the end users, the core
segment of the network is partially traffic offloaded, and the
end users experience better performance in terms of QoS. In
our work, we will evaluate the performance improvement of
an integrated metro/access architecture for VoD delivery with
replicated video servers considering different configurations in
terms of number of replicated servers, meshing degree and
adopted network technologies. We develop a network simulator
in which replicas of video servers (called Metro Servers, or MSs)
are deployed to meet the demand of VoD traffic. In the result
section we compare the performance of the various configurations
and discuss which are the minimum requirements to minimize
blocking of the VoD requests.

Computer Networks, 2013

The increasing diffusion of Automatic Meter Reading (AMR) and the possibility to open the system ... more The increasing diffusion of Automatic Meter Reading (AMR) and the possibility to open the system to third party services has raised many concerns about the protection of personal data related to energy, water or gas consumption, from which details about the habits of the users can be inferred. This paper proposes an infrastructure and a communication protocol for allowing utilities and third parties (Data Consumers) to collect measurement data with different levels of spatial and temporal aggregation from smart meters without revealing the individual measurements to any single node of the architecture.

2014 IEEE Online Conference on Green Communications (OnlineGreenComm), 2014

ABSTRACT Game-theoretic Demand Side Management (DSM) systems have been investigated as a decentra... more ABSTRACT Game-theoretic Demand Side Management (DSM) systems have been investigated as a decentralized approach for the collaborative scheduling of the usage of domestic electrical appliances within a set of households. Such systems allow for the shifting of the starting time of deferrable devices according to the current energy price or power grid condition, in order to reduce the individual monthly bill or to adjust the power load experienced by the grid while meeting the users' preferences about the time of use. The drawback of DSM distributed protocols is that they require each user to communicate his/her own energy consumption patterns to the other users, which may leak sensitive information regarding private habits. This paper proposes a distributed Privacy-Friendly DSM system which preserves users' privacy by integrating data aggregation and perturbation techniques: users decide their schedule according to aggregated consumption measurements perturbed by means of Additive White Gaussian Noise (AWGN). We evaluate the noise power and the size of the set of users required to achieve a given privacy level, quantified by means of the Kullback–Leibler divergence. The performance of our proposed DSM system are compared to the ones obtained by a benchmark system which does not support privacy preservation.

2013 IEEE Global Communications Conference (GLOBECOM), 2013

The privacy-preserving management of energy consumption measurements gathered by Smart Meters pla... more The privacy-preserving management of energy consumption measurements gathered by Smart Meters plays a pivotal role in the Automatic Metering Infrastructure of Smart Grids. Grid users and standardization committees are requiring that utilities and third parties collecting aggregated metering data are prevented from accessing measurements at the household granularity, and data perturbation is a technique used to provide a trade-off between the privacy of individual users and the precision of the aggregated measurements.

Energies, 2014

ABSTRACT The diffusion of Electric Vehicles (EV) fostered by the evolution of the power system to... more ABSTRACT The diffusion of Electric Vehicles (EV) fostered by the evolution of the power system towards the new concept of Smart Grid introduces several technological challenges related to the synergy among electricity-propelled vehicle fleets and the energy grid ecosystem. EVs promise to reduce carbon emissions by exploiting Renewable Energy Sources (RESes) for battery recharge, and could potentially serve as storage bank to flatten the fluctuations of power generation caused by the intermittent nature of RESes by relying on a load aggregator, which intelligently schedules the battery charge/discharge of a fleet of vehicles according to the users' requests and grid's needs. However, the introduction of such vehicle-to-grid (V2G) infrastructure rises also privacy concerns: plugging the vehicles in the recharging infrastructures may expose private information regarding the user's locations and travelling habits. Therefore, this paper proposes a privacy-preserving V2G infrastructure which does not disclose to the aggregator the current battery charge level, the amount of refilled energy, nor the time periods in which the vehicles are actually plugged in. The communication protocol relies on the Shamir Secret Sharing threshold cryptosystem. We evaluate the security properties of our solution and compare its performance to the optimal scheduling achievable by means of an Integer Linear Program (ILP) aimed at maximizing the ratio of the amount of charged/discharged energy to/from the EV's batteries to the grid power availability/request. This way, we quantify the reduction in the effectiveness of the scheduling strategy due to the preservation of data privacy.

2015 International Conference and Workshops on Networked Systems (NetSys), 2015

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2013

Procedia Computer Science, 2014

2013 IEEE International Conference on Smart Grid Communications (SmartGridComm), 2013

Computer Communications, 2012

Computer Networks, 2013

2014 IEEE Online Conference on Green Communications (OnlineGreenComm), 2014

2013 IEEE Global Communications Conference (GLOBECOM), 2013

Energies, 2014

La Comunicazione N.R.&N. 185 FTTx/VDSL2-Vectoring: prestazioni in una rete di accesso a banda ult... more La Comunicazione N.R.&N. 185 FTTx/VDSL2-Vectoring: prestazioni in una rete di accesso a banda ultra larga multi operatore FTTx/VDSL2-Vectoring: performance in a multi operator ultra broadband access network Sommario: L'agenda Digitale per l'Europa (DAE), all'interno della strategia "Europa 2020", fissa come obiettivi per il 2020 il target di 100 Mbit/s per la metà delle abitazioni europee. Al momento la miglior soluzione per raggiungere questo obiettivo è rappresentata dal Fibre To The Home (FTTH) che sarebbe in grado di soddisfare la crescente domanda di accessi ad alta velocità da parte dei cittadini degli stati europei. Tuttavia, il roll-out della rete FTTH comporta costi notevoli sia per la posa delle fibre ottiche che per gli apparati necessari limitando gli investimenti da parte degli operatori. Pertanto, le recenti tecnologie ibride fibra-rame rappresentano una valida alternativa sia dal punto di vista tecnico che economico, sfruttando l'attuale accesso in rame per la rete secondaria, di lunghezza tipica di circa 300 m, combinato con un approccio Fibre To The Cabinet (FTTC) nella rete primaria e riuscendo a soddisfare le richieste di banda larga da parte degli utenti. Un esempio di tale tecnologia è rappresentato dalla tecnica del Vectoring applicata alla tecnologia di accesso VDSL2, che permette di raggiungere velocità di connessione fino a 100 Mbit/s su linee di lunghezza fino a 300 m, le cui reali prestazioni dipendono dalle condizioni dei cavi e dei singoli doppini. Nella prima parte di questo lavoro verranno presentati i risultati della caratterizzazione della degradazione dovuta all'interferenza sul lato lontano (Far End Cross Talk, FEXT) in architetture di rete di accesso Fibre To The Cabinet e Fibre To The Building (FTTB), condotta attraverso l'uso di un emulatore di cavo, ed in particolare l'impatto del Vectoring in uno scenario multi operatore. Nella seconda parte, invece, verranno comparate in un contesto multi operatore le tecnologie standard per le reti in rame, G.fast, VDSL2 e i loro avanzamenti, fornendo i dettagli riguardo ai modelli di attenuazione ed interferenza e mostrando i risultati delle simulazioni. Abstract: The Digital Agenda for Europe, within the "Europe 2020" strategy, establishes the target of 100 Mbit/s Internet access that should be available for 50% of European household, to be achieved until 2020. Fibre to the Home (FTTH) is currently the best solution to meet this requirement that could be able to satisfy the increase of the high speed access usage among the European citizens. Nevertheless, the roll-out of the FTTH network brings high costs for the deployment of the optical fibres and the instruments that limit the investments from the operators. Therefore, the recent hybrid technologies that exploit the current copperbased access for the secondary network, with loop length of 300 m,

In the WiMAX system, the use of the OFDMA technique at the physical layer makes it possible to dy... more In the WiMAX system, the use of the OFDMA technique at the physical layer makes it possible to dynamically select, for each subchannel, the user that can achieve the maximum throughput. This goal can be obtained at the expense of a bad fairness, which can severely penalize some users. Therefore, a proper scheduler is needed at the base station for the assignment of radio resources to users striking a tradeoff between throughput and fairness. This topic is investigated in this paper by considering a family of schedulers based on a utility function characterized by a single parameter. The time-varying channel is modeled according to a Finite State Markov Chain (FSMC). Simulation results illustrate the performance in terms of throughput and fairness in a WiMAX environment in the presence of multipath fading. Our study shows which schedulers strike a balance between throughput and fairness.