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

BGP-Multipath Routing in the Internet

BGP-Multipath, or BGP-M, is a routing technique for balancing traffic load in the Internet. It enables a Border Gateway Protocol (BGP) border router to install multiple ‘equally-good’ paths to a destination prefix. While other multipath routing techniques are deployed at internal routers, BGP-M is deployed at border routers where traffic is shared on multiple border links between Autonomous Systems (ASes). Although there are a considerable number of research efforts on multipath routing, there is so far no dedicated measurement or study on BGP-M in the literature. This thesis presents the first systematic study on BGP-M. I proposed a novel approach to inferring the deployment of BGP-M by querying Looking Glass (LG) servers. I conducted a detailed investigation on the deployment of BGP-M in the Internet. I also analysed BGP-M’s routing properties based on traceroute measurements using RIPE Atlas probes. My research has revealed that BGP-M has already been used in the Internet. In particular, Hurricane Electric (AS6939), a Tier-1 network operator, has deployed BGP-M at border routers across its global network to hundreds of its neighbour ASes on both IPv4 and IPv6 Internet. My research has provided the state-of-the-art knowledge and insights in the deployment, configuration and operation of BGP-M. The data, methods and analysis introduced in this thesis can be immensely valuable to researchers, network operators and regulators who are interested in improving the performance and security of Internet routing. This work has raised awareness of BGP-M and may promote more deployment of BGP-M in future because BGP-M not only provides all benefits of multipath routing but also has distinct advantages in terms of flexibility, compatibility and transparency

Modeling single-phase flow and solute transport across scales

textFlow and transport phenomena in the subsurface often span a wide range of length (nanometers to kilometers) and time (nanoseconds to years) scales, and frequently arise in applications of CO₂ sequestration, pollutant transport, and near-well acid stimulation. Reliable field-scale predictions depend on our predictive capacity at each individual scale as well as our ability to accurately propagate information across scales. Pore-scale modeling (coupled with experiments) has assumed an important role in improving our fundamental understanding at the small scale, and is frequently used to inform/guide modeling efforts at larger scales. Among the various methods, there often exists a trade-off between computational efficiency/simplicity and accuracy. While high-resolution methods are very accurate, they are computationally limited to relatively small domains. Since macroscopic properties of a porous medium are statistically representative only when sample sizes are sufficiently large, simple and efficient pore-scale methods are more attractive. In this work, two Eulerian pore-network models for simulating single-phase flow and solute transport are developed. The models focus on capturing two key pore-level mechanisms: a) partial mixing within pores (large void volumes), and b) shear dispersion within throats (narrow constrictions connecting the pores), which are shown to have a substantial impact on transverse and longitudinal dispersion coefficients at the macro scale. The models are verified with high-resolution pore-scale methods and validated against micromodel experiments as well as experimental data from the literature. Studies regarding the significance of different pore-level mixing assumptions (perfect mixing vs. partial mixing) in disordered media, as well as the predictive capacity of network modeling as a whole for ordered media are conducted. A mortar domain decomposition framework is additionally developed, under which efficient and accurate simulations on even larger and highly heterogeneous pore-scale domains are feasible. The mortar methods are verified and parallel scalability is demonstrated. It is shown that they can be used as “hybrid” methods for coupling localized pore-scale inclusions to a surrounding continuum (when insufficient scale separation exists). The framework further permits multi-model simulations within the same computational domain. An application of the methods studying “emergent” behavior during calcite precipitation in the context of geologic CO₂ sequestration is provided.Petroleum and Geosystems Engineerin

Monitoring Changes in the Stability of Networks Using Eigenvector Centrality

Monitoring networks for anomalies is a typical duty of network operators. The conventional monitoring tools available today tend to almost ignore the topological characteristics of the whole network. This thesis takes a different approach from the conventional monitoring tools, by employing the principle of Eigenvector Centrality. Traditionally, this principle is used to analyse vulnerability and social aspects of networks. The proposed model reveals that topological characteristics of a network can be used to improve the conventional unreliability predictors, and to give a better indicator of its potential weaknesses. An effective expected adjacency matrix, k, is introduced in this work to be used with centrality calculations, and it reflects the factors which affect the reliability of a network, for e.g. link downtimes, link metrics, packet loss, etc. Using these calculations, all network backbone routers are assigned values which correspond to the importance of those routers in comparison to the rest of the network nodes. Furthermore, to observe how vulnerable each node could be, nodes are ranked according to the importance values, where the nodes with high ranking values are more vulnerable. This model is able to analyse temporal stability of the network, observing and comparing the rate of change in node ranking values and connectivity caused by the network link failures. The results show that the proposed model is dynamic, and changes according to the dynamics of the topology of the network, i.e. upgrading, link failures, etc.Master i nettverks- og systemadministrasjo

ICASE

This report summarizes research conducted at the Institute for Computer Applications in Science and Engineering in the areas of (1) applied and numerical mathematics, including numerical analysis and algorithm development; (2) theoretical and computational research in fluid mechanics in selected areas of interest, including acoustics and combustion; (3) experimental research in transition and turbulence and aerodynamics involving Langley facilities and scientists; and (4) computer science

Wireless device identification from a phase noise prospective

As wireless devices become increasingly pervasive and essential, they are becoming both a target for attacks and the very weapon with which such an attack can be carried out. Wireless networks have to face new kinds of intrusion that had not been considered previously because they are linked to the open nature of wireless networks. In particular, device identity management and intrusion detection are two of the most significant challenges in any network security solution but they are paramount for any wireless local area networks (WLANs) because of the inherent non-exclusivity of the transmission medium. The physical layer of 802.11-based wireless communication does not offer security guarantee because any electromagnetic signal transmitted can be monitored, captured, and analyzed by any sufficiently motivated and equipped adversary within the 802.11 device's transmission range. What is required is a form of identification that is nonmalleable (cannot be spoofed easily). For this reason we have decided to focus on physical characteristics of the network interface card (NIC) to distinguish between different wireless users because it can provide an additional layer of security. The unique properties of the wireless medium are extremely useful to get an additional set of information that can be used to extend and enhance traditional security mechanisms. This approach is commonly referred to as radio frequency fingerprinting (RFF), i.e., determining specific characteristics (fingerprint) of a network device component. More precisely, our main goal is to prove the feasibility of exploiting phase noise in oscillators for fingerprinting design and overcome existing limitations of conventional approaches. The intuition behind our design is that the autonomous nature of oscillators among noisy physical systems makes them unique in their response to perturbations and none of the previous work has ever tried to take advantage of thi

Internet of Things From Hype to Reality

The Internet of Things (IoT) has gained significant mindshare, let alone attention, in academia and the industry especially over the past few years. The reasons behind this interest are the potential capabilities that IoT promises to offer. On the personal level, it paints a picture of a future world where all the things in our ambient environment are connected to the Internet and seamlessly communicate with each other to operate intelligently. The ultimate goal is to enable objects around us to efficiently sense our surroundings, inexpensively communicate, and ultimately create a better environment for us: one where everyday objects act based on what we need and like without explicit instructions