A critical look at power law modelling of the Internet

This paper takes a critical look at the usefulness of power law models of the Internet. The twin focuses of the paper are Internet traffic and topology generation. The aim of the paper is twofold. Firstly it summarises the state of the art in power law modelling particularly giving attention to existing open research questions. Secondly it provides insight into the failings of such models and where progress needs to be made for power law research to feed through to actual improvements in network performance.Comment: To appear Computer Communication

Datacenter Traffic Control: Understanding Techniques and Trade-offs

Datacenters provide cost-effective and flexible access to scalable compute and storage resources necessary for today's cloud computing needs. A typical datacenter is made up of thousands of servers connected with a large network and usually managed by one operator. To provide quality access to the variety of applications and services hosted on datacenters and maximize performance, it deems necessary to use datacenter networks effectively and efficiently. Datacenter traffic is often a mix of several classes with different priorities and requirements. This includes user-generated interactive traffic, traffic with deadlines, and long-running traffic. To this end, custom transport protocols and traffic management techniques have been developed to improve datacenter network performance. In this tutorial paper, we review the general architecture of datacenter networks, various topologies proposed for them, their traffic properties, general traffic control challenges in datacenters and general traffic control objectives. The purpose of this paper is to bring out the important characteristics of traffic control in datacenters and not to survey all existing solutions (as it is virtually impossible due to massive body of existing research). We hope to provide readers with a wide range of options and factors while considering a variety of traffic control mechanisms. We discuss various characteristics of datacenter traffic control including management schemes, transmission control, traffic shaping, prioritization, load balancing, multipathing, and traffic scheduling. Next, we point to several open challenges as well as new and interesting networking paradigms. At the end of this paper, we briefly review inter-datacenter networks that connect geographically dispersed datacenters which have been receiving increasing attention recently and pose interesting and novel research problems.Comment: Accepted for Publication in IEEE Communications Surveys and Tutorial

Endogenous TFP and Cross-Country Income Differences

This paper explores the quantitative implications of a class of endogenous growth models for cross-country income differences. These models exhibit international spillovers, no scale effects and conditional convergence, and thus they overcome some difficulties faced by the early generation of endogenous growth models. Cross-country income differences arise in the model as the result of different distortions in the accumulation of rival factors of production, the objects, and in the accumulation of nonrival factor of production, the ideas. We show that object gaps play a much larger role to explain income gaps in models with endogenous TFP than in models with exogenous TFP. We also show, using a carefully calibrated version of the model, that most of the cross-country differences in output per worker are explained by barriers to the accumulation of rival factors (physical and human capital) rather than by barriers to the accumulation of knowledge.endogenous growth, technology diffusion

Securing BGP Communites with Blockchain

Internet is used in our daily life in any technological device we handle. Confidential data is also sent between countries in just few seconds through the Internet. But what if I say that Internet is not perfectly secure and that there are known and opened vulnerabilities? This project aims to solve some of these vulnerabilities explained in a research paper using a decentralized approach and, more specifically, generate multiple benchmarks in order to validate the solution performance. The complete development of the system exceeds the scope for a single technical engineering project. The work has been divided in distinct sections and distributed between two engineers. As all the sections are complementary this document contains the details of all of them. Hyperledger has been used as the base decentralized system, nevertheless, many features have been modified to fulfil our project dependencies

The Dynamics of Internet Traffic: Self-Similarity, Self-Organization, and Complex Phenomena

The Internet is the most complex system ever created in human history. Therefore, its dynamics and traffic unsurprisingly take on a rich variety of complex dynamics, self-organization, and other phenomena that have been researched for years. This paper is a review of the complex dynamics of Internet traffic. Departing from normal treatises, we will take a view from both the network engineering and physics perspectives showing the strengths and weaknesses as well as insights of both. In addition, many less covered phenomena such as traffic oscillations, large-scale effects of worm traffic, and comparisons of the Internet and biological models will be covered.Comment: 63 pages, 7 figures, 7 tables, submitted to Advances in Complex System

Communication links, Productivity, knowledge transfers, growth and income distribution

In this study, we show that banking development, communication links, productivity and income distribution exert a statistically and economically significant positive impact on local economic growth. This effect becomes more pronounced when the financial sector is more liberalized and deregulated. Preceded by the global changes that occurred since the mid-1980s and 1990s, the world has seen continued economic liberalization, increasing privatization and gradual loosening of credit/capital controls by states. The lifting of state controls in the banking sector in the 1980s and 1990s, created a more integrated and competitive financial industry ensuring efficient allocation of bank credits to productive areas. The economic thinking behind all this is that the financial entities, functioning under liberalized monetary regimes operate at higher levels of efficiency and productivity. Productivity improvements may result from different sources, yet the notion that the private sector’s intention to maximize profit leads to productivity improvement is one of the fundamental ones. Put it differently; a deregulated financial system is viewed as an appealing society to invest. Using data from 14 Sub Saharan African Countries (SSA), we examined the growth effects of banking development, communication links, productivity and income distribution over the period 1990 – 2013. We find evidence of significant growth effects of banking development in SSA on industrial components of GDP. Growth in agricultural GDP is positive but not significant

Productivity differences between and within countries

July 6, 200

Technology Catching-up and the Role of Institutions

The aim of the paper is to investigate the role played by differences in Institutional Quality on the process of technology catch-up across countries. Empirical evidence shows how countries endowed with better institutions are those experiencing higher TFP growth rates, faster rates of technology adoption and hence being those more rapidly closing the gap with the frontier. Conversely, countries lacking some minimum institutional level are shown to diverge in the long run and not to catch-up. Some institutions, however, play an ambiguous role in the creation and adoption of technology. We find that the tightening of Intellectual Property Rights reduces the ability of followers to freely imitate technology slowing down their catch-up rate. This negative effect is stronger the farther the countries are found from the frontier. Other institutional categories such as openness to trade, instead, benefit both leaders and followers.TFP, Growth, Institutions, IPRs

Persistent Liquidity Effects and Long Run Money Demand

We present a monetary model in the presence of segmented asset markets that implies a persistent fall in interest rates after a once and for all increase in liquidity. The gradual propagation mechanism produced by our model is novel in the literature. We provide an analytical characterization of this mechanism, showing that the magnitude of the liquidity effect on impact, and its persistence, depend on the ratio of two parameters: the long-run interest rate elasticity of money demand and the intertemporal substitution elasticity. At the same time, the model has completely classical long-run predictions, featuring quantity theoretic and Fisherian properties. The model simultaneously explains the short-run “instability” of money demand estimates as-well-as the stability of long-run interest-elastic money demand.