Assessment on the in-field lightpath QoT computation including connector loss uncertainties

Reliable and conservative computation of the quality of transmission (QoT) of transparent lightpaths (LPs) is a crucial need for software-defined control and management of the wavelength division multiplexing optical transport. The LP QoT is summarized by the generalized SNR (GSNR) that can be computed by a QoT estimator (QoT-E). Within the context of network automation, the QoT-E must rely only on data from the network controller or provided by network elements through common control protocols and data structures. Therefore, given the theoretical accuracy of the QoT-E, the in-field accuracy in the GSNR computation is also determined by the level of knowledge of input parameters. Among these, a fundamental value is the connector loss at the input of each fiber span, which defines the actual power levels triggering the nonlinear effects in the fiber, and so defining the amount of nonlinear interference and spectra tilt due to the stimulated Raman scattering introduced by the fiber span. This value cannot be easily measured and may vary in time because of equipment update or maintenance. In this paper, we consider a lab measurement campaign in which the GSNR has been computed by means of the open source project Gaussian noise model in Python (GNPy) and analyze the computation error distribution. We show how the assumption on the value for the connector loss modifies the GSNR computation error and how the GSNR computation is more conservative while accurate at the lower values for the connector loss. Using the outcome of the measurement campaign carried out in the laboratory, we present results on the error of GSNR computation in a production network, specifically, over two paths of the Microsoft core network. Using GNPy with the assumption of a connector loss of 0.25 dB as derived from the measurement campaign carried out in the laboratory, and using the physical layer description from the network controller, we show that GNPy is not conservative by overestimating the GSNR in only 5% of cases, while in conservative predictions, the underestimation error exceeds 1 dB only for a few outliers. (C) 2020 Optical Society of Americ

Characterising attacks targeting low-cost routers: a MikroTik case study (Extended)

Attacks targeting network infrastructure devices pose a threat to the security of the internet. An attack targeting such devices can affect an entire autonomous system. In recent years, malware such as VPNFilter, Navidade, and SonarDNS has been used to compromise low-cost routers and commit all sorts of cybercrimes from DDoS attacks to ransomware deployments. Routers of the type concerned are used both to provide last-mile access for home users and to manage interdomain routing (BGP). MikroTik is a particular brand of low-cost router. In our previous research, we found more than 4 million MikroTik routers available on the internet. We have shown that these devices are also popular in Internet Exchange infrastructures. Despite their popularity, these devices are known to have numerous vulnerabilities. In this paper, we extend our previous analysis by presenting a long-term investigation of MikroTik-targeted attacks. By using a highly interactive honeypot that we developed, we collected more than 44 million packets over 120 days, from sensors deployed in Australia, Brazil, China, India, the Netherlands, and the United States. The incoming traffic was classified on the basis of Common Vulnerabilities and Exposures to detect attacks targeting MikroTik devices. That enabled us to identify a wide range of activities on the system, such as cryptocurrency mining, DNS server redirection, and more than 3,000 successfully established tunnels used for eavesdropping. Although this research focuses on Mikrotik devices, both the methodology and the publicly available scripts can be easily applied to any other type of network device

Physical layer aware open optical networking

L'abstract è presente nell'allegato / the abstract is in the attachmen

Aircraft interaction with electric field of thundercloud and observations of hard radiation

The purpose of this thesis is to study the relationship between the different phases of lightning flashes and the production of high-energy emissions, as well as highenergy emissions observed from thunderclouds. The data consists of local electric field-, current- and energy measurements on board an aircraft. The lightning attachment points on the aircraft, were identified by the local electric field signatures of the positive and negative leader initiations. Showing a preference of attachment points based on aircraft model and/or flight altitude. Four distinct radiation producing events were identified by the electric fields and x-ray counts measured during the flights. Single photons in association with the stepping of negative leaders, with photon energies close to 100 keV. A correlation between the changes in local electric field, current and the energy of the observed photons were investigated, but were not found. Bursts of photons in association with recoils were observed. Recoils are microsecond fast changes in the local electric field, observed during the return strokes, dart leaders and recoil streamers of a lightning flash. The energies of the observed photon bursts are similar to that of the single photons observed during negative leader steps. Minute long gamma-ray glows from the data set has previously been reported. The findings were used as a basis to search for more gamma-ray glows in the dataset, and a total of 7 new low intensity gamma-ray glow candidates were found. A statistical analysis of the count rates were done for all observed gamma-ray glows to compare the events. Millisecond long x-ray count rate enhancements were observed on 14.01.2016. The lightning flashes were analysed by examining x-ray count rates and local electric fields. The energy spectrum of some of the observed flashes revealed an enhancement at 511 keV, which is the signature energy for positron annihilation. Two previously observed events were compared to two new findings, showing a very good correlation.Masteroppgave i fysikkMAMN-PHYSPHYS39

Observing and Modeling the Physical Layer Phenomena in Open Optical Systems for Network planning and management

L'abstract è presente nell'allegato / the abstract is in the attachmen

The role of customer experience in technology strategy : implications for product adoption in information technology

Thesis (S.M. in Engineering and Management)--Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 104-105).This research identifies and describes the impact of customer experience on the adoption of information technology products. The research findings are applied to the business case of a global technology firm entering into in the cloud computing space. We chose a customer-centric lens in order to better understand how information technology is turned into value for the customer. We complemented well-defined industry-level models of technology adoption by building an original system dynamics model of the relationships of the technology firm with its enterprise customers. Important dynamics were derived from the review and analysis of selected leading edge managerial frameworks that were best suited for the studied business. The market analysis includes interviews with potential enterprise and small business cloud customers, market analysts, and executives at several companies selling cloud computing services. At the firm level, we modeled the effect of different product launch and development strategies and the impact of organizational learning on new business development. The system dynamics model is a management flight simulator that overcomes the limitations of classical management frameworks. The model was calibrated against historical product adoption data that was provided by a leading global information service provider. By running different scenarios, managers may simulate the impact of investments in research and development and marketing. Managers may also test the implications of successfully designing a positive customer experience and of adopting a culture of continuous improvement and business experimentation. The results of this study show that in order to survive and compete in the digital economy, information technology companies need to shed a comfortable yet myopic focus on technology advantage and acquire the capability to develop and execute business strategies focused on excellent and inimitable customer experience. The willingness to experiment and ability to learn are critical success factors. Sustainable competitive advantage also hinges on having the ability to run business experiments, fail, learn from failures and effectively spread that knowledge through the organization.by Mona Masghati Vernon.S.M.in Engineering and Managemen

Physical Layer Aware Optical Networks

This thesis describes novel contributions in the field of physical layer aware optical networks. IP traffic increase and revenue compression in the Telecom industry is putting a lot of pressure on the optical community to develop novel solutions that must both increase total capacity while being cost effective. This requirement is pushing operators towards network disaggregation, where optical network infrastructure is built by mix and match different physical layer technologies from different vendors. In such a novel context, every equipment and transmission technique at the physical layer impacts the overall network behavior. Hence, methods giving quantitative evaluations of individual merit of physical layer equipment at network level are a firm request during network design phases as well as during network lifetime. Therefore, physical layer awareness in network design and operation is fundamental to fairly assess the potentialities, and exploit the capabilities of different technologies. From this perspective, propagation impairments modeling is essential. In this work propagation impairments in transparent optical networks are summarized, with a special focus on nonlinear effects. The Gaussian Noise model is reviewed, then extended for wideband scenarios. To do so, the impact of polarization mode dispersion on nonlinear interference (NLI) generation is assessed for the first time through simulation, showing its negligible impact on NLI generation. Thanks to this result, the Gaussian Noise model is generalized to assess the impact of space and frequency amplitude variations along the fiber, mainly due to stimulated Raman scattering, on NLI generation. The proposed Generalized GN (GGN) model is experimentally validated on a setup with commercial linecards, compared with other modeling options, and an example of application is shown. Then, network-level power optimization strategies are discussed, and the Locally Optimization Global Optimization (LOGO) approach reviewed. After that, a novel framework of analysis for optical networks that leverages detailed propagation impairment modeling called the Statistical Network Assessment Process (SNAP) is presented. SNAP is motivated by the need of having a general framework to assess the impact of different physical layer technologies on network performance, without relying on rigid optimization approaches, that are not well-suited for technology comparison. Several examples of applications of SNAP are given, including comparisons of transceivers, amplifiers and node technologies. SNAP is also used to highlight topological bottlenecks in progressively loaded network scenarios and to derive possible solutions for them. The final work presented in this thesis is related to the implementation of a vendor agnostic quality of transmission estimator for multi-vendor optical networks developed in the context of the Physical Simulation Environment group of the Telecom Infra Project. The implementation of a module based on the GN model is briefly described, then results of a multi-vendor experimental validation performed in collaboration with Microsoft are shown

Ideological Voting on Federal Courts of Appeals: A Preliminary Investigation

For many decades, the United States has been conducting an extraordinary natural experiment: Randomly assigned three-judge panels on courts of appeals produce extensive evidence of the effect of judicial ideology on judges' votes. If the political party of the appointing president is treated as a rough proxy for ideology, then it becomes possible to test three hypotheses: (a) a judge’s votes, in ideologically contested areas, can be predicted by the party of the appointing president; (b) a judge’s ideological tendency, in such areas, will be amplified if the panel has two other judges appointed by an appointing president of the same political party; and (c) a judge’s ideological tendency, in such areas, will be dampened if the panel has no other judge appointed by an appointing president of the same political party. All three hypotheses are confirmed in many areas, including affirmative action, campaign finance, sex discrimination, sexual harassment, piercing the corporate veil, disability discrimination, race discrimination, and review of environmental regulations. An important implication is that panel composition has a strong effect on likely outcomes, thus creating extremely serious problems for the rule of law. Taken as a whole, the evidence suggests that judges frequently issue collegial concurrences, that is, concurrences produced by the unanimous views of the other judges on the panel, and that judges are subject to group polarization, by which groups of like-minded people go to extremes. Notably, all three hypotheses are rejected in the areas of federalism, criminal appeals, and takings of private property, because Republican and Democratic appointees vote essentially alike. In the areas of abortion and capital punishment, the first hypothesis is confirmed, but the second and third are rejected, because judges vote their convictions, and are not affected by the composition of the panel. Disaggregating the data by circuit allows courts of appeals to be ranked along an ideological spectrum; it also shows striking differences between Republican appointees and Democratic appointees on different circuits. Normative implications are briefly explored

Internet Monitor 2014: Reflections on the Digital World: Platforms, Policy, Privacy, and Public Discourse

This publication is the second annual report of the Internet Monitor project at the Berkman Centerfor Internet & Society at Harvard University. As with the inaugural report, this year’s edition is a collaborative effort of the extended Berkman community. Internet Monitor 2014: Reflections on the Digital World includes nearly three dozen contributions from friends and colleagues around the world that highlight and discuss some of the most compelling events and trends in the digitally networked environment over the past year. The result, intended for a general interest audience, brings together reflection and analysis on a broad range of issues and regions — from an examination of Europe’s “right to be forgotten” to a review of the current state of mobile security to an exploration of a new wave of movements attempting to counter hate speech online — and offers it up for debate and discussion. Our goal remains not to provide a definitive assessment of the “state of the Internet” but rather to provide a rich compendium of commentary on the year’s developments with respect to the online space. Last year’s report examined the dynamics of Internet controls and online activity through the actions of government, corporations, and civil society. We focus this year on the interplay between technological platforms and policy; growing tensions between protecting personal privacy and using big data for social good; the implications of digital communications tools for public discourse and collective action; and current debates around the future of Internet governance. The report reflects the diversity of ideas and input the Internet Monitor project seeks to invite. Some of the contributions are descriptive; others prescriptive. Some contain purely factual observations; others offer personal opinion. In addition to those in traditional essay format, contributions this year include a speculative fiction story exploring what our increasingly data-driven world might bring, a selection of “visual thinking” illustrations that accompany a number of essays, a “Year in Review” timeline that highlights many of the year’s most fascinating Internet-related news stories (and an interactive version of which is available at the netmonitor.org), and a slightly tongue-in-cheek “By the Numbers” section that offers a look at the year’s important digital statistics. We believe that each contribution offers insights, and hope they provoke further reflection, conversation, and debate in both offline and online settings around the globe