Ethernet Networks for Real-Time Use in the ATLAS Experiment

Ethernet became today's de-facto standard technology for local area networks. Defined by the IEEE 802.3 and 802.1 working groups, the Ethernet standards cover technologies deployed at the first two layers of the OSI protocol stack. The architecture of modern Ethernet networks is based on switches. The switches are devices usually built using a store-and-forward concept. At the highest level, they can be seen as a collection of queues and mathematically modelled by means of queuing theory. However, the traffic profiles on modern Ethernet networks are rather different from those assumed in classical queuing theory. The standard recommendations for evaluating the performance of network devices define the values that should be measured but do not specify a way of reconciling these values with the internal architecture of the switches. The introduction of the 10 Gigabit Ethernet standard provided a direct gateway from the LAN to the WAN by the means of the WAN PHY. Certain aspects related to the actual use of WAN PHY technology were vaguely defined by the standard. The ATLAS experiment at CERN is scheduled to start operation at CERN in 2007. The communication infrastructure of the Trigger and Data Acquisition System will be built using Ethernet networks. The real-time operational needs impose a requirement for predictable performance on the network part. In view of the diversity of the architectures of Ethernet devices, testing and modelling is required in order to make sure the full system will operate predictably. This thesis focuses on the testing part of the problem and addresses issues in determining the performance for both LAN and WAN connections. The problem of reconciling results from measurements to architectural details of the switches will also be tackled. We developed a scalable traffic generator system based on commercial-off-the-shelf Gigabit Ethernet network interface cards. The generator was able to transmit traffic at the nominal Gigabit Ethernet line rate for all frame sizes specified in the Ethernet standard. The calculation of latency was performed with accuracy in the range of +/- 200 ns. We indicate how certain features of switch architectures may be identified through accurate throughput and latency values measured for specific traffic distributions. At this stage, we present a detailed analysis of Ethernet broadcast support in modern switches. We use a similar hands-on approach to address the problem of extending Ethernet networks over long distances. Based on the 1 Gbit/s traffic generator used in the LAN, we develop a methodology to characterise point-to-point connections over long distance networks. At higher speeds, a combination of commercial traffic generators and high-end servers is employed to determine the performance of the connection. We demonstrate that the new 10 Gigabit Ethernet technology can interoperate with the installed base of SONET/SDH equipment through a series of experiments on point-to-point circuits deployed over long-distance network infrastructure in a multi-operator domain. In this process, we provide a holistic view of the end-to-end performance of 10 Gigabit Ethernet WAN PHY connections through a sequence of measurements starting at the physical transmission layer and continuing up to the transport layer of the OSI protocol stack

Resilience mechanisms for carrier-grade networks

In recent years, the advent of new Future Internet (FI) applications is creating ever-demanding requirements. These requirements are pushing network carriers for high transport capacity, energy efficiency, as well as high-availability services with low latency. A widespread practice to provide FI services is the adoption of a multi-layer network model consisting in the use of IP/MPLS and optical technologies such as Wavelength Division Multiplexing (WDM). Indeed, optical transport technologies are the foundation supporting the current telecommunication network backbones, because of the high transmission bandwidth achieved in fiber optical networks. Traditional optical networks consist of a fixed 50 GHz grid, resulting in a low Optical Spectrum (OS) utilization, specifically with transmission rates above 100 Gbps. Recently, optical networks have been undergoing significant changes with the purpose of providing a flexible grid that can fully exploit the potential of optical networks. This has led to a new network paradigm termed as Elastic Optical Network (EON). In recent years, the advent of new Future Internet (FI) applications is creating ever-demanding requirements. A widespread practice to provide FI services is the adoption of a multi-layer network model consisting in the use of IP/MPLS and optical technologies such as Wavelength Division Multiplexing (WDM). Traditional optical networks consist of a fixed 50 GHz grid, resulting in a low Optical Spectrum (OS) utilization. Recently, optical networks have been undergoing significant changes with the purpose of providing a flexible grid that can fully exploit the potential of optical networks. This has led to a new network paradigm termed as Elastic Optical Network (EON). Recently, a new protection scheme referred to as Network Coding Protection (NCP) has emerged as an innovative solution to proactively enable protection in an agile and efficient manner by means of throughput improvement techniques such as Network Coding. It is an intuitive reasoning that the throughput advantages of NCP might be magnified by means of the flexible-grid provided by EONs. The goal of this thesis is three-fold. The first, is to study the advantages of NCP schemes in planning scenarios. For this purpose, this thesis focuses on the performance of NCP assuming both a fixed as well as a flexible spectrum grid. However, conversely to planning scenarios, in dynamic scenarios the accuracy of Network State Information (NSI) is crucial since inaccurate NSI might substantially affect the performance of an NCP scheme. The second contribution of this thesis is to study the performance of protection schemes in dynamic scenarios considering inaccurate NSI. For this purpose, this thesis explores prediction techniques in order to mitigate the negative effects of inaccurate NSI. On the other hand, Internet users are continuously demanding new requirements that cannot be supported by the current host-oriented communication model.This communication model is not suitable for future Internet architectures such as the so-called Internet of Things (IoT). Fortunately, there is a new trend in network research referred to as ID/Locator Split Architectures (ILSAs) which is a non-disruptive technique to mitigate the issues related to host-oriented communications. Moreover, a new routing architecture referred to as Path Computation Element (PCE) has emerged with the aim of overcoming the well-known issues of the current routing schemes. Undoubtedly, routing and protection schemes need to be enhanced to fully exploit the advantages provided by new network architectures.In light of this, the third goal of this thesis introduces a novel PCE-like architecture termed as Context-Aware PCE. In a context-aware PCE scenario, the driver of a path computation is not a host/location, as in conventional PCE architectures, rather it is an interest for a service defined within a context.En los últimos años la llegada de nuevas aplicaciones del llamado Internet del Futuro (FI) está creando requerimientos sumamente exigentes. Estos requerimientos están empujando a los proveedores de redes a incrementar sus capacidades de transporte, eficiencia energética, y sus prestaciones de servicios de alta disponibilidad con baja latencia. Es una práctica sumamente extendida para proveer servicios (FI) la adopción de un modelo multi-capa el cual consiste en el uso de tecnologías IP/MPLS así como también ópticas como por ejemplo Wavelength Division Multiplexing (WDM). De hecho, las tecnologías de transporte son el sustento del backbone de las redes de telecomunicaciones actuales debido al gran ancho de banda que proveen las redes de fibra óptica. Las redes ópticas tradicionales consisten en el uso de un espectro fijo de 50 GHz. Esto resulta en una baja utilización del espectro Óptico, específicamente con tasas de transmisiones superiores a 100 Gbps. Recientemente, las redes ópticas están experimentado cambios significativos con el propósito de proveer un espectro flexible que pueda explotar el potencial de las redes ópticas. Esto ha llevado a un nuevo paradigma denominado Redes Ópticas Elásticas (EON). Por otro lado, un nuevo esquema de protección llamado Network Coding Protection (NCP) ha emergido como una solución innovadora para habilitar de manera proactiva protección eficiente y ágil usando técnicas de mejora de throughput como es Network Coding (NC). Es un razonamiento lógico pensar que las ventajas relacionadas con throughput de NCP pueden ser magnificadas mediante el espectro flexible proveído por las redes EONs. El objetivo de esta tesis es triple. El primero es estudiar las ventajas de esquemas NCP en un escenario de planificación. Para este propósito, esta tesis se enfoca en el rendimiento de NCP asumiendo un espectro fijo y un espectro flexible. Sin embargo, contrario a escenarios de planificación, en escenarios dinámicos la precisión relacionada de la Información de Estado de Red (NSI) es crucial, ya que la imprecisión de NSI puede afectar sustancialmente el rendimiento de un esquema NCP. La segunda contribución de esta tesis es el estudio del rendimiento de esquemas de protección en escenarios dinámicos considerando NSI no precisa. Para este propósito, esta tesis explora técnicas predictivas con el propósito de mitigar los efectos negativos de NSI impreciso. Por otro lado, los usuarios de Internet están demandando continuamente nuevos requerimientos los cuales no pueden ser soportados por el modelo de comunicación orientado a hosts. Este modelo de comunicaciones no es factible para arquitecturas FI como es el Internet de las cosas (IoT). Afortunadamente, existe un nueva línea investigativa llamada ID/Locator Split Architectures (ILSAs) la cual es una técnica no disruptiva para mitigar los problemas relacionadas con el modelo de comunicación orientado a hosts. Además, un nuevo esquema de enrutamiento llamado as Path Computation Element (PCE) ha emergido con el propósito de superar los problemas bien conocidos de los esquemas de enrutamiento tradicionales. Indudablemente, los esquemas de enrutamiento y protección deben ser mejorados para que estos puedan explotar las ventajas introducidas por las nuevas arquitecturas de redes. A luz de esto, el tercer objetivo de esta tesis es introducir una nueva arquitectura PCE denominada Context-Aware PCE. En un escenario context-aware PCE, el objetivo de una acción de computación de camino no es un host o localidad, como es el caso en lo esquemas PCE tradicionales. Más bien, es un interés por un servicio definido dentro de una información de contexto

All-healing weapon: the value of Oplopanax horridus root bark in the treatment of type 2 diabetes

While Indigenous Peoples live in an incredibly diverse geographical array with significant differences in language, culture, and history, there is a shared experience of an increased prevalence of type 2 diabetes and impaired glucose tolerance as compared to the dominant or colonizer populations. Indigenous patients with type 2 diabetes face multiple barriers to disease self-management: poverty, chronic stress, cultural oppression, limited access to healthy food or exercise, inadequate housing and limited resources to pay for medications. Epidemiological models of type 2 diabetes disregard the social determinants that play a prominent role in the disease’s predominance among the world’s Indigenous Peoples, creating a chasm between health care providers and the sick. This division can be reconciled through the recognition of cultural and spiritual connotations in disease management and the incorporation of sacred foods and medicinal plants in diabetes treatment care programs. For millennia, Indigenous Peoples of the Pacific Northwest have administered the inner bark of the stalk and roots of Oplopanax horridus (devil’s-club) to treat illness and disease; including difficult childbirth, skin infections, cancer, lung hemorrhages, tuberculosis, and diabetes. Devil’s-club is mentioned in written records of oral traditions and ethnographies, confirming the presence of this plant as a powerful symbol of medicine. These oral traditions, rooted in the culture for hundreds of years, serve as testimonies that speak to the sacred and medicinal value of this plant. The antidiabetic capability of this prickly shrub has been the object of Western pharmacological inquiry since 1938 when scientists recorded the extract to effect hypoglycemia in rabbits, validating the use of devil’s-club tea to remedy symptoms of diabetes. These findings propelled my independent research in which I gathered and prepared the root bark to be extracted and tested against hyperglycemia in vitro by conducting a series of tests, especially focusing on the extracts’ activity with the digestive enzymes that break down carbohydrates into the simple sugars used by the body for energy. By synthesizing a discussion of Indigenous Knowledge systems, ethnopharmacological inquiry, and biochemical analysis, I will demonstrate that the inner bark of Oplopanax horridus (devil’s-club) contains antidiabetic activity as affirmed by oral testimonies of Pacific Northwest Indigenous Peoples

Control plane routing in photonic networks

The work described in the thesis investigates the features of control plane functionality for routing wavelength paths to serve a set of sub-wavelength demands. The work takes account of routing problems only found in physical network layers, notably analogue transmission impairments. Much work exists on routing connections for dynamic Wavelength-Routed Optical Networks (WRON) and to demonstrate their advantages over static photonic networks. However, the question of how agile the WRON should be has not been addressed quantitatively. A categorization of switching speeds is extended, and compared with the reasons for requiring network agility. The increase of effective network capacity achieved with increased agility is quantified through new simulations. It is demonstrated that this benefit only occurs within a certain window of network fill; achievement of significant gain from a more-agile network may be prevented by the operator’s chosen tolerable blocking probability. The Wavelength Path Sharing (WPS) scheme uses semi-static wavelengths to form unidirectional photonic shared buses, reducing the need for photonic agility. Making WPS more practical, novel improved routing algorithms are proposed and evaluated for both execution time and performance, offering significant benefit in speed at modest cost in efficiency. Photonic viability is the question of whether a path that the control plane can configure will work with an acceptable bit error rate (BER) despite the physical transmission impairments encountered. It is shown that, although there is no single approach that is simple, quick to execute and generally applicable at this time, under stated conditions approximations may be made to achieve a general solution that will be fast enough to enable some applications of agility. The presented algorithms, analysis of optimal network agility and viability assessment approaches can be applied in the analysis and design of future photonic control planes and network architectures

The relative contribution of free radicals to the oxidation chain of Dimethylsulphide in the marine boundary layer

Hydroxylradikale (OH) sind die dominierende photochemische Senke von Dimethylsulfid(DMS) in der reinen marinen Atmosphäre und beherrschen den globalen Abbau von DMS. In Gebieten mit starker Luftverschmutzung kann das Oxidationsvermögen von nächtlich gebildeten Nitratradikalen (NO3) jenes von OH am Tage bei Weitem übertreffen. Während so genannter �Bromexplosionen� kann Bromoxid (BrO) auf lokaler Ebene eine dominerende Senke für DMS darstellen. Der Abbau von DMS steht am Anfang eines komplexen Oxidationsmechanismus dessen Ablauf wesentlich durch die Mischungsverhältnisse von Sticktoffoxiden (NO,NO2,NO3), Ozon, OH und Peroxyradikalen bestimmt wird. Im Verlauf dieser Arbeit wurden drei Messkampagnen in der marinen Grenzschicht durchgeführt. Das Ziel war der Vergleich der Konzentration von Halogen- und Stickstoffoxiden, sowie weiterer Radikale mit denen von DMS und dessen Oxidationsprodukten DMSO und MSA. Die Ergebnisse der ersten Messstudie im östlichen Mittelmeer(Kreta) ermöglichen eine ausgiebige Untersuchung der Wechselwirkung von DMS und NO3. Anschliessende Messungen in der Hudson Bay (Kanada) stellen den ersten bodengestützen Nachweis von BrO in der subarktischen Grenzschicht dar. Die Ergebnisse weisen auf einen erheblichen Einfluss von Bromoxid auf den Oxidationsprozess von DMS in diesem Gebiet hin. Die gemessenen Mischungsverhältnisse von Halogen und Stickstoffradikalen während der dritten Messkampagne im südlichen Indischen Ozean sind zu gering um direkte Bezüge zum Abbauprozess von DMS zu erkennen. Die gemessen Iodoxid-Konzentrationen können jedoch einen zusätzlichen Beitrag zum Ozonabbau leisten und durch die Proportionalität der OH-Produktionsrate zur Ozonkonzentration zu einer verringerten OH Bildung führen

Manipulation of Metabotropic and AMPA Glutamate Receptors in the Brain

The consequences of the pharmacological manipulation of metabotropic and AMPA glutamate receptor-mediated events in the rat brain were investigated in this thesis. [14C]2- deoxyglucose autoradiography was used to explore modifications in physiological brain function following the systemic administration of two novel selective agonists with actions on group II metabotropic glutamate receptors (mGluRs) and following the intracerebral manipulation of the hippocampus using a selective AMPA antagonist. The putative role of group II mGluRs in neuroprotection was also examined. An in vivo model of cerebral ischaemia together with two in vitro models of neurotoxicity with group II mGluR agonist intervention were used to study the potential of group II mGluR agonists in protecting cellular elements from neurotoxic insults. Mapping brain function with group II selective mGluR agonists Local rates of cerebral glucose use were measured using the [14C]2-deoxyglucose autoradiographic technique to examine the functional consequences of the systemic administration of the novel mGluR agonist LY3 54740, and a related analogue LY3 79268, in the conscious rat. Both LY354740 (0.3, 3.0, 30 mg/kg) and LY379268 (0.1, 1.0, 10 mg/kg) produced dose-dependent changes in glucose utilisation. LY3 54740 produced anatomically widespread reductions in glucose use, while LY3 79268 affected a smaller number of brain regions which displayed increases in glucose metabolism. After LY354740 (3.0mg/kg) administration, 4 out of 42 brain regions demonstrated statistically significant changes from vehicle treated controls; red nuclei (-16%), mammillary body (-25%), anteroventral thalamic nucleus (-29%) and the superficial layer of the superior colliculus (+50%). An additional 15 regions displayed significant reductions in function-related glucose use (P). Both compounds displayed a similar anatomical pattern of altered glucose metabolism in the limbic system. Reductions were noted in the anteroventral thalamic nucleus, lateral habenular nucleus, molecular layer of the hippocampus and the mammillary body (P < 0.05) following both agonists Glucose utilisation in components of different sensory systems were altered following the activation of mGluR2/3. In animals treated with LY354740, reductions in function-related glucose use were observed in areas associated with vision, while those treated with LY3 79268 demonstrated elevated glucose utilisation in primary auditory areas. This study has demonstrated that the [14C]2-deoxyglucose autoradiographic technique provides a reliable means of mapping functional events in the brain. It has highlighted fundamental differences in the regional effects of the two agonists and has served to demonstrate the important functional involvement of the limbic system together with the participation of components of different sensory systems in response to the activation of mGluR2 and mGluR3 with LY354740 and LY379268. Regional mapping of cerebral function following hippocampal manipulation The [14C]2-deoxyglucose autoradiographic technique was used to investigate changes in brain function during, and following, the localised 7 day infusion of the selective AMPA/kainate receptor antagonist LY326325 in the conscious rat. During the period of drug infusion, anatomically circumscribed changes in glucose use were measured in animals treated with LY326325 compared with aCSF (artificial cerebrospinal fluid) treated control animals. Reductions in glucose utilisation were demonstrated in the molecular layer of the dorsal hippocampus (-23%, P<0.002) but not in the molecular layer of the ventral hippocampus. The maximal reduction in glucose use measured in the molecular layer of the hippocampus was observed adjacent to the implant site, along a dorsal axis relative to the implant site. Other than a marked elevation in function-related glucose use in the superficial layers of the entorhinal cortex, rates of glucose utilisation in the remaining regions of the CNS were minimally affected during the period of drug infusion. (Abstract shortened by ProQuest.)