A STUDY ON WAVEBAND ROUTING OPTICAL NETWORKS EMPLOYING WAVEBAND SELECTIVE SWITCH-BASED CROSS-CONNECTS

A waveband cross-connect architecture is proposed, utilizing small-scale wavebandselective switches to make the best use of present optical switch technologies and exploit opticalwaveband switching for creating cost-effective large capacity optical path networks. Anappropriate network design algorithm is then developed for the waveband routing opticalnetworks employing the waveband cross-connect architecture. Numerical experiments prove thatapplying the small-scale waveband selective switch-based node architecture offers a significantswitch scale reduction. The effect of the waveband capacity selection on the overall switch scalereduction was also investigated

Topics in access, storage, and sensor networks

In the first part of this dissertation, Data Over Cable Service Interface Specification (DOCSIS) and IEEE 802.3ah Ethernet Passive Optical Network (ETON), two access networking standards, are studied. We study the impact of two parameters of the DOCSIS protocol and derive the probability of message collision in the 802.3ah device discovery scheme. We survey existing bandwidth allocation schemes for EPONs, derive the average grant size in one such scheme, and study the performance of the shortest-job-first heuristic. In the second part of this dissertation, we study networks of mobile sensors. We make progress towards an architecture for disconnected collections of mobile sensors. We propose a new design abstraction called tours which facilitates the combination of mobility and communication into a single design primitive and enables the system of sensors to reorganize into desirable topologies alter failures. We also initiate a study of computation in mobile sensor networks. We study the relationship between two distributed computational models of mobile sensor networks: population protocols and self-similar functions. We define the notion of a self-similar predicate and show when it is computable by a population protocol. Transition graphs of population protocols lead its to the consideration of graph powers. We consider the direct product of graphs and its new variant which we call the lexicographic direct product (or the clique product). We show that invariants concerning transposable walks in direct graph powers and transposable independent sets in graph families generated by the lexicographic direct product are uncomputable. The last part of this dissertation makes contributions to the area of storage systems. We propose a sequential access detect ion and prefetching scheme and a dynamic cache sizing scheme for large storage systems. We evaluate the cache sizing scheme theoretically and through simulations. We compute the expected hit ratio of our and competing schemes and bound the expected size of our dynamic cache sufficient to obtain an optimal hit ratio. We also develop a stand-alone simulator for studying our proposed scheme and integrate it with an empirically validated disk simulator

A Power Efficient Server-to-Server Wireless Data Center Network Architecture Using 60 GHz Links

Data Centers have become the digital backbone of the modern society with the advent of cloud computing, social networking, big data analytics etc. They play a vital role in processing a large amount of information generated. The number of data centers and the servers present in them have been on the rise over the last decade. This has eventually led to the increase in the power consumption of the data center due to the power-hungry interconnect fabric which consists of switches, routers and switching fabric necessary for communication in the data center. Moreover, a major portion of the power consumed in a data center belongs to cooling infrastructure. The data center’s complex cabling prevents the heat dissipation by obstructing the air flow resulting in the need for a cooling infrastructure. Additionally, the complex cabling in traditional data centers poses design and maintenance challenges. In this work, these problems of traditional data centers are addressed by designing a unique new server-to-server wireless Data Center Network (DCN) architecture. The proposed design methodology uses 60GHz unlicensed millimeter-wave bands to establish direct communication links between servers in a DCN without the need for a conventional fabric. This will reduce the power consumption of the DCN significantly by getting rid of the power-hungry switches along with an increase in the independency in communication between servers. In this work, the previous traffic models of a data center network are studied and a new traffic model very similar to the actual traffic in a data center is modeled and used for simulating the DCN environment. It is estimated that the proposed DCN architecture’s power consumption is lowered by six to ten times in comparison to the existing conventional DCN architecture. Having established the power model of a server-to-server wireless DCN in terms of its power consumption, we demonstrate that such a power-efficient wireless DCN can sustain the traffic requirements encountered and provide data rates that are comparable to traditional DCNs. We have also compared the efficiency and performance of the proposed DCN architecture with some of the other novel DCN architectures like DCell, BCube with the same traffic

Efficient computation and communication management for all-pairs interactions

Big data continues to grow in size for all sciences. New methods like those proposed are needed to further reduce memory footprints and distribute work equally across compute nodes both in local HPC systems and rented cluster resources in the cloud. Modern infrastructures have evolved to support these big data computations and that includes key pieces like our internet backbones and data center networks. Many optical networks face heterogeneous communication requests requiring topologies to be efficient and fault tolerant. The all-pairs problem requires all elements (computation datasets or communication nodes) to be paired with all other elements. These all-pairs problems occur in many research fields and have significant impacts, which has led to their continued interest. We proposed using cyclic quorum sets to efficiently manage all-pairs computations. We proved these sets have an all-pairs property that allows for minimal data replication and for distributed, load balanced, and communication-less computation management. The quorums are $O\left(\frac{N}{\sqrt{P}}\right)$ in size, up to 50% smaller than dual $\frac{N}{\sqrt{P}}$ array implementations, and significantly smaller than solutions requiring all data. Scaling from 16 to 512 cores (1 to 32 compute nodes) and using real dataset inputs, application experiments demonstrated scalability with greater than 150x (super-linear) speedup and less than 1/4th the memory usage per process. Cyclic quorum sets can provided benefits to more than just computations. The sets can also provide a guarantee that all pairs of optical nodes in a network can communicate. Our evaluation analyzed the fault tolerance of routing optical cycles based on cyclic quorum sets. With this method of topology construction, unicast and multicast communication requests do not need to be known or even modeled a priori. In the presence of network single-link faults, our simulated cycle routing had greater than 99% average fault coverage. Hence, even in the presence of a network fault, the optical networks could continue operation of nearly all node pair communications. Lastly, we proposed a generalized $R$ redundant cyclic quorum set. These sets guarantee all pairs of nodes occur at least $R$ times. When applied to routing cycles in optical networks, this technique provided almost fault-tolerant communications. More importantly, when applied using only single cycles rather than the standard paired cycles, the generalized $R$ redundancy technique almost halved the necessary light-trail resources while maintaining the fault tolerance and dependability expected from cycle-based routing. \section*{Problem Description} Big Data in recent years has become a focal point for science and commerce. As datasets grow larger, traditional methods and algorithms are challenged on whether they are able to truly scale. This has led to phrases like, swimming in sensors, drowning in data. Our work addresses some of the challenges facing a particular type of big data interaction. The interaction considered requires all elements in a set to interact with all other elements in the set. The all-pairs interaction is a general computation or communication problem that occurs frequently and can be as simple as considering the shaking of hands by all attendees to a party. More formally there is set $E_N$, where there are $N$ elements indexed $0$ to $\left(N-1\right)$. $$E_N = \left\lbrace e_0, e_1, ... , e_{N-1} \right\rbrace$$ The elements in this general formulation can be simple, single communication node or single item data structures, e.g., $E_N$ could simply be all nodes in a network or be a large array of $N$ values. Or, elements can be complex data structures with many fields / values. Fields are not restricted to a single data type either, as many big data problems can rely on heterogeneous datasets. The all-pairs interaction considers all possible pairs of elements, $\binom{N}{2}$. $$\left\lbrace \left(e_0,e_1\right), \left(e_0,e_2\right), ... , \left(e_0,e_{N-1}\right), \left(e_1,e_2\right), \left(e_1,e_3\right) , ... , \left(e_1, e_{N-1}\right) , ... , \left(e_{N-2},e_{N-1}\right) \right\rbrace$$ While the simple hand shake example could be considered a symmetric interaction. e_i \leftrightarrow e_j , i The all-pairs interaction can be more generally represented by two separate interactions to better represent the computational or communication complexity in those problems where the all-pairs operation is not commutative. \[ e_i \rightarrow e_j, i \[ e_i \leftarrow e_j, i The computational complexity of this general algorithmic form is not daunting. \[\binom{N}{2} = \frac{\left( N-1\right) N}{2} = O\left( N^2\right) In fact, even for pair computations that do not have the commutative property, the complexity is unchanged. In general, polynomial $O\left(N^2\right)$ computations are considered highly computationally scalable. When performing an all-pairs data interaction on the big data scale sizes, while the computational complexity theoretically is manageable, the data management becomes complex. The problem definition inherently requires access to the entire dataset, such that every data element can be paired and processed with every other data element in the set. When the datasets exceed a system\u27s memory size, this presents a challenge, which our methods address. \section*{Solution Approach} For efficiency and distributed control, it is common in distributed systems and algorithms to group nodes into intersecting sets referred to as quorum sets. Our management techniques rely on the established quorum set theories for their efficiencies and management. We then proved an all-pairs property of cyclic quorum sets, which is central to guaranteeing that all-pairs of elements (nodes or data) are able to interact in the system. The all-pairs data computation problem requires all data elements to be paired with all other data elements. These all-pairs problems occur in many science fields, which has led to their continued interest. Our research addresses the memory and computation time challenges of the general all-pairs big data interaction computations through the use of memory efficient computation management techniques. Proposed were methods using distributed computing to share the computational workload. Although the problem definition requires every data element to have access to and interact with the entire dataset, our cyclic quorum set techniques relax this restriction in distributed systems. This computation management is used to reduce memory resource requirements per node and enable big data scalability. Implementation evaluation of a large bioinformatics application demonstrated scalability on real datasets with linear and at times super-linear speedups. Reductions in memory requirements per node allowed for processing larger datasets that would not have been feasible on a single node either due to memory or time requirements. Similar cyclic quorum set techniques were used to address efficient and fault tolerant communication routing challenges in optical networking. Cycle-based optical network routing, whether using SONET rings or p-cycles, provide the sufficient reliability in networks. Light-trails forming a cycle in the network allow broadcasts within a cycle to be used for efficient multicast communications. Using the proven ``all-pairs\u27\u27 property of cyclic quorum sets, we could guarantee all pairs of nodes will occur in one or more quorums, so efficient, arbitrary unicast communication can occur between any two nodes. Efficient broadcasts to all network nodes are possible by a node broadcasting to all quorum cycles to which it belongs ($O\left(\sqrt{N}\right)$.) We analyzed node pair communications in networks, specifically, the fault tolerance aspects of using cyclic quorum sets to route cycles. Observed was better than 99% average single fault coverage and some node pair communications were protected by more than one cycle. Exploiting this redundant node pair protections revealed even greater resource efficiencies. Common cycle routing techniques will use pairs of cycles to achieve both routing and fault-tolerance, which uses substantial resources and creates the potential for underutilization. Instead, when we intentionally designed cyclic quorum sets with $R$ redundant pairs of nodes and utilized the $R$ redundancy within the quorum cycles to replace the pair of cycles with just a single cycle, we saw network resource usage almost halved. Our analysis of several networks showed $R=2$ redundant single cycles had 96.60 - 99.37% single link fault coverage, while reducing resource usage by 42.9 - 47.18% on average. Increasing redundancy to $R=3$ redundant cycles maintained a 93.23 - 99.34% average fault coverage even with two simultaneous link faults and used 38.85 - 42.39% fewer resources on average

Topological optimization of quantum key distribution networks

A Quantum Key Distribution (QKD) network is an infrastructure that allows the realization of the key distribution cryptographic primitive over long distances and at high rates with information-theoretic security. In this work, we consider QKD networks based on trusted repeaters from a topology viewpoint, and present a set of analytical models that can be used to optimize the spatial distribution of QKD devices and nodes in specific network configurations in order to guarantee a certain level of service to network users, at a minimum cost. We give details on new methods and original results regarding such cost minimization arguments applied to QKD networks. These results are likely to become of high importance when the deployment of QKD networks will be addressed by future quantum telecommunication operators. They will therefore have a strong impact on the design and requirements of the next generation of QKD devices.Comment: 25 pages, 4 figure

Satellite integration in 5G : contribution on network architectures and traffic engineering solutions for hybrid satellite-terrestrial mobile backhauling

The recent technological advances in the satellite domain such as the use of High Throughput Satellites (HTS) with throughput rates that are magnitudes higher than with previous ones, or the use of large non- Geostationary Earth Orbit (GEO) satellites constellations, etc, are reducing the price per bit and enhancing the Quality of Service (QoS) metrics such as latency, etc., changing the way that the capacity is being brought to the market and making it more attractive for other services such as satellite broadband communications. These new capabilities coupled with the advantages offered by satellite communications such as the unique wide-scale geographical coverage, inherent broadcast/multicast capabilities and highly reliable connectivity, anticipate new opportunities for the integration of the satellite component into the 5G ecosystem. One of the most compelling scenarios is mobile backhauling, where satellite capacity can be used to complement the terrestrial backhauling infrastructure, not only in hard to reach areas, but also for more efficient traffic delivery to Radio Access Network (RAN) nodes, increased resiliency and better support for fast, temporary cell deployments and moving cells. In this context, this thesis work focuses on achieving better satellite-terrestrial backhaul network integration through the development of Traffic Engineering (TE) strategies to manage in a better way the dynamically steerable satellite provisioned capacity. To do this, this thesis work first takes the steps in the definition of an architectural framework that enables a better satellite-terrestrial mobile backhaul network integration, managing the satellite capacity as a constituent part of a Software Defined Networking (SDN) -based TE for mobile backhaul network. Under this basis, this thesis work first proposes and assesses a model for the analysis of capacity and traffic management strategies for hybrid satellite-terrestrial mobile backhauling networks that rely on SDN for fine-grained traffic steering. The performance analysis is carried out in terms of capacity gains that can be achieved when the satellite backhaul capacity is used for traffic overflow, taking into account the placement of the satellite capacity at different traffic aggregation levels and considering a spatial correlation of the traffic demand. Later, the thesis work presents the development of SDN-based TE strategies and algorithms that exploits the dynamically steerable satellite capacity provisioned for resilience purposes to better utilize the satellite capacity by maximizing the network utility under both failure and non-failure conditions in some terrestrial links, under the consideration of elastic, inelastic and unicast and multicast traffic. The performance analysis is carried out in terms of global network utility, fairness and connexion rejection rates compared to non SDN-based TE applications. Finally, sustained in the defined architectural framework designs, the thesis work presents an experimental Proof of Concept (PoC) and validation of a satellite-terrestrial backhaul links integration solution that builts upon SDN technologies for the realization of End-to-End (E2E) TE applications in mobile backhauling networks with a satellite component, assessing the feasibility of the proposed SDN-based integration solution under a practical laboratory setting that combines the use of commercial, experimentation-oriented and emulation equipment and software.Los recientes avances tecnológicos en el dominio de los satélites, como el uso de satélites de alto rendimiento (HTS) con tasas de rendimiento que son magnitudes más altas que los anteriores, o el uso de grandes constelaciones de satélites de órbita no geoestacionaria (GEO), etc. están reduciendo el precio por bit y mejorando las métricas de Calidad de Servicio (QoS) como la latencia, etc., cambiando la forma en que la capacidad se está llevando al mercado, y haciéndola más atractiva para otros servicios como las comunicaciones de banda ancha por satélite. Estas nuevas capacidades, junto con las ventajas ofrecidas por las comunicaciones por satélite, como la cobertura geográfica a gran escala, las inherentes capacidades de difusión / multidifusión y la conectividad altamente confiable, anticipan nuevas oportunidades para la integración de la componente satelital al ecosistema 5G. Uno de los escenarios más atractivos es el backhauling móvil, donde la capacidad del satélite se puede usar para complementar la infraestructura de backhauling terrestre, no solo en áreas de difícil acceso, sino también para la entrega de tráfico de manera más eficiente a los nodos de la Red de Acceso (RAN), una mayor resiliencia y mejor soporte para implementaciones rápidas y temporales de células, así como células en movimiento. En este contexto, este trabajo de tesis se centra en lograr una mejor integración de la red híbrida de backhaul satélital-terrestre, a través del desarrollo de estrategias de ingeniería de tráfico (TE) para gestionar de una mejor manera la capacidad dinámicamente orientable del satélite. Para hacer esto, este trabajo de tesis primero toma los pasos en la definición de un marco de arquitectura que permite una mejor integración de una red híbrida satelital-terrestre de backhaul móvil, gestionando la capacidad del satélite como parte constitutiva de un TE basado en Software Defined Networking (SDN). Bajo esta base, este trabajo de tesis primero propone y evalúa un modelo para el análisis de la capacidad y las estrategias de gestión del tráfico para redes híbridas satelital-terrestre de backhaul móvil basadas en SDN para la dirección de tráfico. El análisis de rendimiento se lleva a cabo en términos de aumento de capacidad que se puede lograr cuando la capacidad de la red de backhaul por satélite se utiliza para el desborde de tráfico, teniendo en cuenta la ubicación de la capacidad del satélite en diferentes niveles de agregación de tráfico y considerando una correlación espacial de la demanda de tráfico. Posteriormente, el trabajo de tesis presenta el desarrollo de estrategias y algoritmos de TE basados en SDN que explotan la capacidad dinámicamente orientable del satelite, provista con fines de resiliencia para utilizar de mejor manera la capacidad satelital al maximizar la utilidad de red en condiciones de falla y no falla en algunos enlaces terrestres, y bajo la consideración de tráfico elástico, inelástico y de unidifusión y multidifusión. El análisis de rendimiento se lleva a cabo en términos de tasas de rechazo, de utilidad, y equidad en comparación con las aplicaciones de TE no basadas en SDN. Finalmente, basado en la definición del diseño de marco de arquitectura, el trabajo de tesis presenta una Prueba de concepto (PoC) experimental y la validación de una solución de integración de enlaces de backhaul satelital-terrestre que se basa en las tecnologías SDN para la realización de aplicaciones de TE de extremo a extremo (E2E) en redes de backhaul móviles, evaluando la viabilidad de la solución propuesta de integración basada en SDN en un entorno práctico de laboratorio que combina el uso de equipos y software comerciales, orientados a la experimentación y emulación.Postprint (published version

Multi-Object Tracking System based on LiDAR and RADAR for Intelligent Vehicles applications

El presente Trabajo Fin de Grado tiene como objetivo el desarrollo de un Sistema de Detección y Multi-Object Tracking 3D basado en la fusión sensorial de LiDAR y RADAR para aplicaciones de conducción autónoma basándose en algoritmos tradicionales de Machine Learning. La implementación realizada está basada en Python, ROS y cumple requerimientos de tiempo real. En la etapa de detección de objetos se utiliza el algoritmo de segmentación del plano RANSAC, para una posterior extracción de Bounding Boxes mediante DBSCAN. Una Late Sensor Fusion mediante Intersection over Union 3D y un sistema de tracking BEV-SORT completan la arquitectura propuesta.This Final Degree Project aims to develop a 3D Multi-Object Tracking and Detection System based on the Sensor Fusion of LiDAR and RADAR for autonomous driving applications based on traditional Machine Learning algorithms. The implementation is based on Python, ROS and complies with real-time requirements. In the Object Detection stage, the RANSAC plane segmentation algorithm is used, for a subsequent extraction of Bounding Boxes using DBSCAN. A Late Sensor Fusion using Intersection over Union 3D and a BEV-SORT tracking system complete the proposed architecture.Grado en Ingeniería en Electrónica y Automática Industria