Quality of service, security and trustworthiness for network slices

(English) The telecommunications' systems are becoming much more intelligent and dynamic due to the expansion of the multiple network types (i.e., wired, wireless, Internet of Things (IoT) and cloud-based networks). Due to this network variety, the old model of designing a specific network for a single purpose and so, the coexistence of different and multiple control systems is evolving towards a new model in which the use of a more unified control system is able to offer a wide range of services for multiple purposes with different requirements and characteristics. To achieve this situation, the networks have become more digital and virtual thanks to the creation of the Software-Defined Networking (SDN) and the Network Function Virtualization (NFV).Network Slicing takes the strengths from these two technologies and allows the network control systems to improve their performance as the services may be deployed and their interconnection configured through multiple-transport domains by using NFV/SDN tools such as NFV-Orchestrators (NFV-O) and SDN Controllers. This thesis has the main objective to contribute to the state of the art of Network Slicing, with a special focus on security aspects towards the architectures and processes to deploy, monitor and enforce secured and trusted resources to compose network slices. Finally, this document is structured in eight chapters: Chapter 1 provides the motivation and objectives of this thesis which describes to where this thesis contributes and what it was expected to study, evaluate and research. Chapter 2 presents the background necessary to understand the following chapters. This chapter presents a state of the art with three clear sections: 1) the key technologies necessary to create network slices, 2) an overview about the relationship between Service Level Agreements (SLAs) and network slices with a specific view on Security Service Level Agreements (SSLAs), and, 3) the literature related about distributed architectures and systems and the use of abstraction models to generate trust, security, and avoid management centralization. Chapter 3 introduces the research done associated to Network Slicing. First with the creation of network slices using resources placed multiple computing and transport domains. Then, this chapter illustrates how the use of multiple virtualization technologies allows to have more efficient network slices deployments and where each technology fits better to accomplish the performance improvements. Chapter 4 presents the research done about the management of network slices and the definition of SLAs and SSLAs to define the service and security requirements to accomplish the expected QoS and the right security level. Chapter 5 studies the possibility to change at certain level the trend to centralise the control and management architectures towards a distributed design. Chapter 6 follows focuses on the generation of trust among service resources providers. This chapter first describes how the concept of trust is mapped into an analytical system and then, how the trust management among providers and clients is done in a transparent and fair way. Chapter 7 is devoted to the dissemination results and presents the set of scientific publications produced in the format of journals, international conferences or collaborations. Chapter 8 concludes the work and outcomes previously presented and presents possible future research.(Català) Els sistemes de telecomunicacions s'estan tornant molt més intel·ligents i dinàmics degut a l'expansió de les múltiples classes de xarxes (i.e., xarxes amb i sense fils, Internet of Things (IoT) i xarxes basades al núvol). Tenint en consideració aquesta varietat d'escenaris, el model antic de disseny d'una xarxa enfocada a una única finalitat i, per tant, la una coexistència de varis i diferents sistemes de control està evolucionant cap a un nou model en el qual es busca unificar el control cap a un sistema més unificat capaç d'oferir una amplia gama de serveis amb diferents finalitats, requeriments i característiques. Per assolir aquesta nova situació, les xarxes han hagut de canviar i convertir-se en un element més digitalitzat i virtualitzat degut a la creació de xarxes definides per software i la virtualització de les funcions de xarxa (amb anglès Software-Defined Networking (SDN) i Network Function Virtualization (NFV), respectivament). Network Slicing fa ús dels punts forts de les dues tecnologies anteriors (SDN i NFV) i permet als sistemes de control de xarxes millorar el seu rendiment ja que els serveis poden ser desaplegats i la seva interconnexió a través de múltiples dominis de transport configurada fent servir eines NFV/SDN com per exemple orquestradors NFV (NFV-O) i controladors SDN. Aquesta tesi té com a objectiu principal, contribuir en diferents aspectes a la literatura actual al voltant de les network slices. Més concretament, el focus és en aspectes de seguretat de cara a les arquitectures i processos necessaris per desplegar, monitoritzar i aplicar recursos segurs i fiables per generar network slices. Finalment, el document es divideix en 8 capítols: El Capítol 1correspon a la introducció de la temàtica principal, la motivació per estudiar-la i els objectius plantejats a l'inici dels estudis de doctorat. El Capítol 2 presenta un recull d'elements i exemples en la literatura actual per presentar els conceptes bàsics i necessaris en relació a les tecnologies NFV, SDN i Network Slicing. El Capítol 3 introdueix el lector a les tasques i resultats obtinguts per l'estudiant respecte l'ús de network slices enfocades en escenaris amb múltiples dominis de transport i posteriorment en la creació i gestió de network slices Híbrides que utilitzen diferents tecnologies de virtualització. El Capítol 4 s'enfoca en l'ús d’eines de monitorització tant en avaluar i assegurar que es compleixen els nivells esperats de qualitat del servei i sobretot de qualitat de seguretat de les network slices desplegades. Per fer-ho s'estudia l'ús de contractes de servei i de seguretat, en anglès: Service Level Agreements i Security Service Level Agreements. El Capítol 5 estudia la possibilitat de canviar el model d'arquitectura per tal de no seguir centralitzant la gestió de tots els dominis en un únic element, aquest capítol presenta la feina feta en l'ús del Blockchain com a eina per canviar el model de gestió de recursos de múltiples dominis cap a un punt de vista cooperatiu i transparent entre dominis. El Capítol 6 segueix el camí iniciat en el capítol anterior i presenta un escenari en el qual a part de tenir múltiples dominis, també tenim múltiples proveïdors oferint un mateix servei (multi-stakeholder). En aquest cas, l'objectiu del Blockchain passa a ser la generació, gestió i distribució de paràmetres de reputació que defineixin un nivell de fiabilitat associat a cada proveïdor. De manera que, quan un client vulgui demanar un servei, pugui veure quins proveïdors són més fiables i en quins aspectes tenen millor reputació. El Capítol 7 presenta les tasques de disseminació fetes al llarg de la tesi. El Capítol 8 finalitza la tesi amb les conclusions finals.Postprint (published version

Performance study of the IEEE 802.11p and ETSI GeoNetworking protocols

C-ITS is a research field that looks to generate complex ad-hoc networks in which the nodes themselves must think on their own and where any connected node must help the nodes around to know and understand how the network works at any moment and also to preview how it must behave from one second to the next one in order to solve traffic management problems and accidents as fast as possible. The main objective of this project is to evaluate two protocols belonging to the ETSI protocol stack (802.11p and GeoNetworking) through a simulation software based on Omnet++. By using multiple parameters like propagation models, loss probability and some others, some results are presented to evaluate whether the two protocols fulfil the network requirements or not. At the end of the project an improvement proposal for one of the two defined services is presented

Estudi de la viabilitat econòmica de la generació d'energia fotovoltaica a les cobertes de l'Eixample

El canvi climàtic és una realitat acceptada i confirmada per tota la comunitat científica internacional, que reclama actuacions fermes per la descarbonització del planeta, sent necessari prendre decisions dràstiques a nivell mundial, com reduir les emissions de CO₂ i invertir més recursos en energies renovables. L’objectiu principal d’aquest estudi és donar resposta a la població a la pregunta sobre la viabilitat d’instal·lar plaques solars fotovoltaiques a les cobertes. Aquest estudi se centra en el barri de l’Eixample de Barcelona, ja que gràcies a la seva estructura modular és més fàcil extrapolar els resultats. A través d’una base de dades creada especialment per aquest treball, s’ha caracteritzat un bloc tipus de l’Eixample que serà l’objecte del nostre estudi. En aquest bloc es definirà el consum energètic, el nombre d’habitatges i l’energia generada per aconseguir la configuració que obté un millor rendiment econòmic. Les hipòtesis realitzades en el bloc tipus, s’han aplicat per simular altres configuracions diferents a la del bloc tipus, diferents superfícies útils, consums i bateries, així com també s’han aplicat les hipòtesis al concepte de micro-xarxa energètica, on es valorarà l’impacte econòmic.Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminan

A cluster-randomized trial of hydroxychloroquine for prevention of Covid-19

Background: current strategies for preventing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are limited to nonpharmacologic interventions. Hydroxychloroquine has been proposed as a postexposure therapy to prevent coronavirus disease 2019 (Covid-19), but definitive evidence is lacking. Methods: we conducted an open-label, cluster-randomized trial involving asymptomatic contacts of patients with polymerase-chain-reaction (PCR)-confirmed Covid-19 in Catalonia, Spain. We randomly assigned clusters of contacts to the hydroxychloroquine group (which received the drug at a dose of 800 mg once, followed by 400 mg daily for 6 days) or to the usual-care group (which received no specific therapy). The primary outcome was PCR-confirmed, symptomatic Covid-19 within 14 days. The secondary outcome was SARS-CoV-2 infection, defined by symptoms compatible with Covid-19 or a positive PCR test regardless of symptoms. Adverse events were assessed for up to 28 days. Results: the analysis included 2314 healthy contacts of 672 index case patients with Covid-19 who were identified between March 17 and April 28, 2020. A total of 1116 contacts were randomly assigned to receive hydroxychloroquine and 1198 to receive usual care. Results were similar in the hydroxychloroquine and usual-care groups with respect to the incidence of PCR-confirmed, symptomatic Covid-19 (5.7% and 6.2%, respectively; risk ratio, 0.86 [95% confidence interval, 0.52 to 1.42]). In addition, hydroxychloroquine was not associated with a lower incidence of SARS-CoV-2 transmission than usual care (18.7% and 17.8%, respectively). The incidence of adverse events was higher in the hydroxychloroquine group than in the usual-care group (56.1% vs. 5.9%), but no treatment-related serious adverse events were reported. Conclusions: postexposure therapy with hydroxychloroquine did not prevent SARS-CoV-2 infection or symptomatic Covid-19 in healthy persons exposed to a PCR-positive case patient. (Funded by the crowdfunding campaign YoMeCorono and others; BCN-PEP-CoV2 ClinicalTrials.gov number, NCT04304053.)

Measurement and Interpretation of Fermion-Pair Production at LEP energies above the Z Resonance

This paper presents DELPHI measurements and interpretations of cross-sections, forward-backward asymmetries, and angular distributions, for the e+e- -> ffbar process for centre-of-mass energies above the Z resonance, from sqrt(s) ~ 130 - 207 GeV at the LEP collider. The measurements are consistent with the predictions of the Standard Model and are used to study a variety of models including the S-Matrix ansatz for e+e- -> ffbar scattering and several models which include physics beyond the Standard Model: the exchange of Z' bosons, contact interactions between fermions, the exchange of gravitons in large extra dimensions and the exchange of sneutrino in R-parity violating supersymmetry.Comment: 79 pages, 16 figures, Accepted by Eur. Phys. J.

A Determination of the Centre-of-Mass Energy at LEP2 using Radiative 2-fermion Events

Using e+e- -> mu+mu-(gamma) and e+e- -> qqbar(gamma) events radiative to the Z pole, DELPHI has determined the centre-of-mass energy, sqrt{s}, using energy and momentum constraint methods. The results are expressed as deviations from the nominal LEP centre-of-mass energy, measured using other techniques. The results are found to be compatible with the LEP Energy Working Group estimates for a combination of the 1997 to 2000 data sets.Comment: 20 pages, 6 figures, Accepted by Eur. Phys. J.

Study of Tau-pair Production in Photon-Photon Collisions at LEP and Limits on the Anomalous Electromagnetic Moments of the Tau Lepton

Tau-pair production in the process e+e- -> e+e-tau+tau- was studied using data collected by the DELPHI experiment at LEP2 during the years 1997 - 2000. The corresponding integrated luminosity is 650 pb^{-1}. The values of the cross-section obtained are found to be in agreement with QED predictions. Limits on the anomalous magnetic and electric dipole moments of the tau lepton are deduced.Comment: 20 pages, 9 figures, Accepted by Eur. Phys. J.

A Measurement of the Tau Hadronic Branching Ratios

The exclusive and semi-exclusive branching ratios of the tau lepton hadronic decay modes (h- v_t, h- pi0 v_t, h- pi0 pi0 v_t, h- \geq 2pi0 v_t, h- \geq 3pi0 v_t, 2h- h+ v_t, 2h- h+ pi0 v_t, 2h- h+ \geq 2pi0 v_t, 3h- 2h+ v_t and 3h- 2h+ \geq 1pi0 v_t) were measured with data from the DELPHI detector at LEP.Comment: 53 pages, 18 figures, Accepted by Eur. Phys. J.

Study of Leading Hadrons in Gluon and Quark Fragmentation

The study of quark jets in e+e- reactions at LEP has demonstrated that the hadronisation process is reproduced well by the Lund string model. However, our understanding of gluon fragmentation is less complete. In this study enriched quark and gluon jet samples of different purities are selected in three-jet events from hadronic decays of the Z collected by the DELPHI experiment in the LEP runs during 1994 and 1995. The leading systems of the two kinds of jets are defined by requiring a rapidity gap and their sum of charges is studied. An excess of leading systems with total charge zero is found for gluon jets in all cases, when compared to Monte Carlo Simulations with JETSET (with and without Bose-Einstein correlations included) and ARIADNE. The corresponding leading systems of quark jets do not exhibit such an excess. The influence of the gap size and of the gluon purity on the effect is studied and a concentration of the excess of neutral leading systems at low invariant masses (<~ 2 GeV/c^2) is observed, indicating that gluon jets might have an additional hitherto undetected fragmentation mode via a two-gluon system. This could be an indication of a possible production of gluonic states as predicted by QCD.Comment: 19 pages, 6 figures, Accepted by Phys. Lett.

Evidence for an Excess of Soft Photons in Hadronic Decays of Z^0

Soft photons inside hadronic jets converted in front of the DELPHI main tracker (TPC) in events of qqbar disintegrations of the Z^0 were studied in the kinematic range 0.2 < E_gamma < 1 GeV and transverse momentum with respect to the closest jet direction p_T < 80 MeV/c. A clear excess of photons in the experimental data as compared to the Monte Carlo predictions is observed. This excess (uncorrected for the photon detection efficiency) is (1.17 +/- 0.06 +/- 0.27) x 10^{-3} gamma/jet in the specified kinematic region, while the expected level of the inner hadronic bremsstrahlung (which is not included in the Monte Carlo) is (0.340 +/- 0.001 +/- 0.038) x 10^{-3} gamma/jet. The ratio of the excess to the predicted bremsstrahlung rate is then (3.4 +/- 0.2 +/- 0.8), which is similar in strength to the anomalous soft photon signal observed in fixed target experiments with hadronic beams.Comment: 37 pages, 9 figures, Accepted by Eur. Phys. J.