Thesis (M.S.C.I.T.)--Regis University, Denver, Colo., 2005. / Title from PDF title page (viewed on Dec. 5, 2005). Includes bibliographical references.

No description available.

Approved for public release; distribution is unlimited / A study of SONET network management applications and the load they impart to the network is conducted to provide a better understanding of the capability of various management approaches. In this study, a SONET network is set up in the Advanced Networking Laboratory of the Naval Postgraduate School using four Cisco ONS 15454s. Next, two Element Management Systems, the Cisco Transport Controller and the Cisco Transport Manager, are deployed onto the SONET network. Subsequently, the network traffic of the Element Management Systems is captured and analyzed using a packet analyzer. Link utilization of the two tools is computed using the first-order statistics of the captured traffic distributions. In addition, the Hurst parameter is estimated using the variance-index plot technique (which uses higher-orders statistics of the modeled distributions) to determine the captured traffic's degree of self-similarity. Finally, the calculated utilization is extrapolated to obtain the link utilization for 2500 network elements (the maximum number supported by the Cisco Transport Manager). The result obtained is useful in determining the maximum number of network elements (Cisco ONS 15454s) that the Cisco Transport Manager can support from a network loading point of view. / Civilian, Ministry of Defense, Singapore

No description available.

Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, 2004. / Thesis Advisor(s): John C. McEachen. Includes bibliographical references (p. 51-52). Also available online.

La arquitectura de las redes de transporte actuales está basada en la tecnología de transporte SDH (Synchronous Digital Hierarchy). Las redes SDH se han diseñado y están optimizadas básicamente para el transporte del tráfico de voz. Actualmente, se está experimentando un crecimiento exponencial del volumen de tráfico de datos. Este crecimiento se debe a que el protocolo IP se está consolidando como capa de integración para servicios múltiples, algunos de ellos con requerimientos de Calidad de Servicio (QoS) y también a la introducción de tecnología de acceso de alta velocidad. Las características estadísticas del tráfico de datos son diferentes respecto a las del tráfico telefónico. De hecho, el tráfico IP se caracteriza no solo por su asimetría sino por su naturaleza dinámica, ya que presenta fluctuaciones o picos difíciles de predecir a priori.Como consecuencia, ha surgido la necesidad de emigrar desde las actuales redes hacia una estructura más flexible y dinámica, optimizada para el transporte de tráfico de datos.La evolución de las actuales redes de transporte incluye trasladar todas las funcionalidades de SDH (conmutación, monitorización de la calidad de la señal, protección frente a fallos) a nivel óptico. El resultado consistirá en una red de transporte óptica (Optical Transport Network, OTN) basada en tecnología DWDM, con Optical Cross Connects (OXC) para encaminar canales ópticos de forma permanente o conmutada (Automatic Switched Optical Network, ASON).Uno de los principales problemas a solucionar por las operadoras de red es la eficiente gestión de la capacidad disponible, y así evitar por un lado la necesidad de sobredimensionar la red de transporte y por el otro optimizar la utilización de los recursos mediante la definición de estrategias de ingeniería de tráfico.La introducción de las redes de transporte a conmutación automática (ASON), capaces de proporcionar conexiones ópticas bajo demanda, es considerada como la solución de red que puede proporcionar el rápido y flexible aprovisionamiento de ancho de banda. Tal funcionalidad, posible gracias a la definición de un plano de control basado en el paradigma GMPLS, puede ser usada para gestionar de manera dinámica los recursos disponibles, tanto a nivel SDH como a nivel óptico, respondiendo de forma eficiente a las fluctuaciones del tráfico generado por la red cliente. Sin embargo, el problema que surge es el diseño de un mecanismo para disparar automáticamente las peticiones de establecimiento de circuitos SDH/canales ópticos conmutados.En este sentido, la primera contribución de esta Tesis es el diseño de un mecanismo de disparo de peticiones de circuitos SDH/canales ópticos basado en la monitorización y predicción del tráfico de la red cliente (IP). Además, el mecanismo diseñado incluye la definición de políticas de ingeniería de tráfico para la optimización de la utilización del elevado ancho de banda proporcionado por las conexiones ópticas. Concretamente, el mecanismo diseñado se caracteriza por la interoperabilidad entre la capa cliente y la capa de transporte.La Tesis incluye también una contribución sobre el diseño de una metodología para el dimensionado de la redes ASON, basada en la caracterización del tráfico de llegadas de peticiones de establecimiento de conexiones, mediante su valor medio y el factor de peakedness.Por otro lado, la optimización de los recursos disponibles es muy crítica cuando se produce un fallo en la infraestructura de red debido a la necesidad de encontrar rutas alternativas para el tráfico afectado. Debido al gran volumen de tráfico a transportar, un fallo en la infraestructura de red puede tener graves consecuencias económicas. Por ejemplo, un corte de una única fibra óptica produce el fallo de todas las longitudes de onda que transporta; de esta manera la pérdida de cada longitud de onda operante a 2.5 Gbps o 10 Gbps puede resultar en el corte de un enorme número de conexiones en curso. Por lo tanto, a mayor capacidad, mayor es la importancia de la rapidez y rendimiento de los mecanismos de protección y recuperación.Las estrategias de protección frente a fallos deben ser simples, minimizar las pérdidas de tráfico y deben utilizar eficientemente los recursos disponibles.La recién estandardizada tecnología para redes de entornos metropolitanos, Resilient Packet Ring (RPR) se caracteriza por mecanismos de protección optimizados para minimizar el tiempo de recuperación en caso de fallos. Además, tales mecanismos no requieren la asignación a priori de recursos de red a utilizar solamente en caso de fallos.Por lo que respecta a los mecanismos de recuperación, se puede optar por una estrategia de recuperación en una sola capa (single layer recovery) o alternativamente por una estrategia de recuperación en múltiples capas (multi-layer recovery), donde en la recuperación intervienen diferentes capas de la estructura de red. El esquema de recuperación multi-capas más fácil de implementar es el consistente en ejecutar los mecanismos de protección/recuperación de los distintos niveles de manera paralela e independiente. Esta estrategia no es, sin embargo, la más eficiente. La interoperabilidad entre los mecanismos de protección de las diferentes capas permite reaccionar más rápidamente a los fallos que se pueden producir.La segunda contribución de esta Tesis es el diseño de una política de coordinación entre los mecanismos de protección proporcionados por RPR y los mecanismos de protección definidos por la capa óptica. Concretamente, la estrategia diseñada se basa en la interoperabilidad entre la capa RPR y la capa de transporte (OTN) para redes de entornos metropolitanos. La estrategia diseñada permite, además, la optimización de los recursos de red. / The main objective of the traffic engineering (TE) strategies is the efficient mapping of the actual traffic onto the available network resources. Legacy Time Division Multiplexing-based networking architecture was basically designed to transport symmetric voice traffic. However, the volume of data traffic is increasing at explosive rate and already dominates the voice traffic. This is due to a progressive migration of many applications and services over the Internet Protocol (IP) and also to a deeper and deeper introduction of high-speed access technologies. Also there is the convergence towards the IP of real-time applications (i.e. multimedia applications) which have very strict QoS requirements. The statistical characteristics of the data traffic are rather different from those of telephone traffic. Specifically, IP traffic is highly dynamic showing predictable and unpredictable traffic surges/peaks. Such surges are caused by unexpected events such as user' behaviours, weather conditions, accidents, fault, etc. This can cause significant fluctuations of the aggregated data traffic to be carried by the transport networks. The current SONET/SDH transport networks (but also the incoming Optical Transport Networks) tend to be static, which means that connections (SONET/SDH circuits and light paths) are provided manually through the Network Management System. The manual configuration is time consuming, which means that weeks or even months are needed to provide high bandwidth connections.The highly dynamic IP traffic pattern does not match with the static provisioning of capacity of the optical transport networks, leading to non-optimal utilization of the resources (i.e. network congestion or under-utilization of resources).Thus, the problem that arises for Network Operators is how to efficiently manage the network resources in the transport network to efficiently respond to the changes in the traffic demands reaching, in such a way, traffic engineering objectives. The introduction of the Automatic Switched Optical Networks (ASON), which is able to provide dynamically switched connections on demand, is recognized as the enabling solution to meet the requirement of fast and flexible end-to-end bandwidth provisioning. The automatic set up and tear down of optical connections can be used for the dynamic management of the transport network resources to track significant variations in the volume of the network client traffic. In such a context, a mechanism that triggers demands to set up/tear down light paths as a function of the variation of the client traffic to be transported is required. The design of a multi-layer traffic engineering (MTE) strategy for IP/MPLS over ASON/GMPLS networks to face with the dynamic traffic demands is the first contribution of this Ph.D. Thesis. It has to be underlined that the policies for the set up of the light paths are out of the scope of this work. In fact, it is assumed that the set up/tear down of the switched connections is in charge of the ASON control plane, namely the GMPLS-based routing and signalling protocols.As a second contribution, it is presented a practical approach for ASON networks dimensioning purposes based on the approximate characterization of the traffic arrival process, through its mean and the peakedness factor. On the other hand, the optimization of the utilization of network resources is very critical when failures occur in the network as a consequence of the need of rerouting the affected traffic. The increase of the capacity and number of wavelengths that can be multiplexed onto the same fibre, each one carrying 2.5 or 10 Gbps client signals, implies that outages of the network infrastructure can have serious economical and social consequences. Network recovery/resilience, i.e., the capability of the networks to efficiently recover from failures, has become of vital importance. Thus, optical transport networks need to be very robust to face failures. The protection mechanisms should be designed basically with the aim to be simple, to minimize the traffic losses and to optimize the utilization of the network resources.Survivability strategies in current transport networks are based on the pre-allocation of network resources to be used only to switch (route) the affected traffic in case of failures. In legacy multi-layer networks, each layer (e.g. IP, SDH) has its own protection mechanism built in, independent from the other layers. Network recovery basically relies on the SONET/SDH network layer. Indeed, different mechanisms, based on the protection approach, have been proposed that allow fast recovery within the target of 50 ms. Nevertheless, SONET/SDH protection is mainly limited to ring topologies and it is not able to distinguish between different priorities of traffic and it has not vision of higher layer failures.The emerging packet-based Resilient Packet Ring (RPR) technology for metropolitan networks provides powerful protection mechanisms that minimize the time needed to restore the traffic without the pre-allocation of resources.To face to failures, the resilience single-layer strategy (a single layer has the responsibility for the recovery) is very simple from the implementation point of view. However it may not be able to efficiently recover the network from all kind of failures that can occur. Therefore, multi-layer resilience (various network layers can participate to the recovery actions) provides better performance not only in terms of protection but also in terms of resources optimization. Multi-layer resilience strategies require coordinating the recovery mechanisms provided by each layer. In such a context, another contribution of this Ph.D. Thesis is the design and evaluation of a multi-layer resilience mechanism to be used in the IP over RPR over intelligent optical transport network for metropolitan environment to efficiently face with a wide range of network outages, while optimizing the utilization of the network resources. Its novelty relies on the interworking required between the RPR and the optical transport layer. Finally, the fourth contribution of the Thesis deals with the optimization of the bandwidth utlization of the RPR rings taking benefits from the automatic switching of optical connections capabilities of the underlying ASON/GMPLS networks.

ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV / High speed real-time data transportation is most important for telemetry systems, especially for large-scale distributed systems. This paper introduces a STDM (Sync Time Division Multiplexing) network structure for data transportation between devices in telemetry systems. The data in these systems is transported through virtual channels between devices. In addition, a proper frame format is designed based on PCM format to meet the needs of synchronization and real-time transportation in large-scale distributed telemetry systems.

Thesis (M.C.S.)--Carleton University, 2002. / Includes bibliographical references (p. 151-153). Also available in electronic format on the Internet.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006. / A Synchronous Digital Hierarchy (SDH) point-to-point bi-directional link was implemented at a base Synchronous Transfer Mode level 1 (STM 1) signal rate. The full STM-1 multiplexer was implemented and the functional code developed to Virtual Container level 4 (VC4) level. The implementation was realized using a Software Defined Radio (SDR) architecture that managed and linked the SDH atomic units into a STM-1 SDH multiplexing structure. These atomic units have been well defined in recommendation G.707 [1]. The functional description of each unit was based on the G.783 [8] recommendation which specifies a library of basic building blocks and set of rules by which these atomic functions should be combined into various functional layers. These layers interconnect to ultimately form a bi-directional path in the SDH network. A SDH Management Sub network (SMS) was implemented using a graphical user interface to perform a monitoring function for the bi-directional link.

Αντικείμενο της διατριβής είναι η επίδειξη μεθόδων, που βρίσκουν εφαρμογή, τόσο ειδικότερα στην σχεδίαση πολύπλοκων ψηφιακών μικροηλεκτρονικών κυκλωμάτων μεγάλης ταχύτητας, για τηλεπικοινωνιακά δίκτυα οπτικών ινών, όσο και γενικότερα για την επίλυση θεμάτων χρονισμού, που προκύπτουν κατά την υλοποίηση πολύπλοκων ολοκληρωμένων συστημάτων πάνω σε chip. Όσον αφορά, τον χώρο των τηλεπικοινωνιακών κυκλωμάτων, παρουσιάζονται μέθοδοι, τόσο για την συνολική οργάνωση του ολοκληρωμένου κυκλώματος, όσο και για την κυκλωματική υλοποίηση λειτουργικών μονάδων κοινών σε τηλεπικοινωνιακά κυκλώματα, με απαιτήσεις υψηλής ταχύτητας, χαμηλής κατανάλωσης, και ταυτόχρονης συνύπαρξης πολλαπλών ρολογιών. Η επίδειξη των προτεινόμενων μεθόδων καθώς και η επαλήθευση της ορθότητά τους, πραγματοποιείται, μέσα από την υλοποίηση σε πυρίτιο, ενός πολύπλοκου τηλεπικοινωνιακού ολοκληρωμένου κυκλώματος, με υψηλές απαιτήσεις ταχύτητας λειτουργίας. Όσον αφορά, τον γενικότερο χώρο της σχεδίασης πολύπλοκων ολοκληρωμένων System-on-Chip (SoC), παρουσιάζονται μέθοδοι για την επίλυση προβλημάτων χρονισμού, στα σύγχρονα ψηφιακά ολοκληρωμένα κυκλώματα, που σχετίζονται με την διάδοση και τον πολλαπλασιασμό της συχνότητας του ρολογιού, στο εσωτερικό των κυκλωμάτων αυτών. Πιο συγκεκριμένα, παρουσιάζονται μέθοδοι που μπορούν να εφαρμοστούν, τόσο για την εξάλειψη της παρέκκλισης, μεταξύ των κόμβων των εσωτερικών ρολογιών, όσο και για την εξάλειψη της παρέκκλισης μεταξύ εξωτερικού και εσωτερικού ρολογιού, στα ολοκληρωμένα κυκλώματα. Όσον αφορά το δεύτερο, η συχνότητα του εσωτερικού ρολογιού δεν ταυτίζεται απαραίτητα με αυτήν του εξωτερικού, αλλά επιτρέπεται να έχει πολλαπλάσια τιμή από αυτήν. Για την ευθυγράμμιση του εσωτερικού με το εξωτερικό ρολόι, προτείνεται η συστηματική μέθοδος LCD-SMD, η οποία είναι κατάλληλη για χρήση σε ολοκληρωμένα όπου επικρατούν συνθήκες μακρύ οδηγού ρολογιού, παράγει εσωτερικό ρολόι πολλαπλάσιο του εξωτερικού με σταθερό 50% duty-cycle, έχει μικρό χρόνο κλειδώματος, και χρησιμοποιεί εξ’ ολοκλήρου ψηφιακές λογικές πύλες. Η επικύρωση της ορθότητας των προτεινόμενων μεθόδων για θέματα χρονισμού, γίνεται κατά ένα μέρος με υλοποίηση σε πυρίτιο, και κατά ένα άλλο μέρος με εξομοιώσεις. / This Thesis aims to demonstrate design methods that can be applied as much in the design of high complexity, high speed, digital integrated circuits for optical fiber networks, as more generally to resolve timing issues, arising during the implementation of integrated circuits (IC’s). Specifically, in this Thesis we present methods for the holistic organization of a digital integrated circuit (driven by the needs imposed by nowadays telecommunications area), as well as methods regarding circuit implementation of various common functional units in telecommunications circuits that require high speed, low power and multiple clocks. The proposed methods are demonstrated and validated through the silicon implementation of a complex telecom integrated circuit (SDH framer). The design of the here-above mentioned chips lie into the more general area of the complex integrated Systems-on-Chips (SoCs). The methods developed in the Thesis, concern the distribution and frequency multiplication of the clock signal, inside the chip. In particular, we address between others, methods to remove the skew between the internal clock nodes, as well as methods to remove the skew between the internal and external clock. The internal clock frequency is allowed to be a multiple of the external clock frequency. For the alignment of the internal with the external clock, the systematic open-loop method LCD-SMD has been proposed, which is applicable to IC’s with long clock driver conditions. Through this method, we accomplish the generation of an internal clock with multiple frequencies than the external, while preserving a constant 50% duty-cycle. The method results into a fast lock time, and employs only standard digital logic gates. The proposed methods are validated both by silicon implementation and by simulations.