141 research outputs found
Metro Area Network Single Link Failure- Fast Spanning Tree Reconnection
Due to Affordability, ease of maintenance and ubiquity, Ethernet has become a preferred technology to be deployed in to LAN, MAN and WAN networks. Even though Ethernet has being used widely for switched communication it is not meet requirement for Metro Area Networks in terms of network resilience. In this paper, author propose the fast spanning tree re-connection formula, especially for Metro Area Ethernet networks to manage any single link failure, and it has most important feature of fast recovery, backup capacity grantees and ease of fast recovery. If in case of link failure on a spanning tree, a distributed failure recovery protocol is activated to rebuild the broken spanning tree. This is re-connecting the link but not a spanning tree. Author presents the details of the protocol, which including failure notification and forwarding table reconfiguration manual. The Integer linear programming (ILP) is formulated to reconnect-links as it pre-configured. The result of optimization gives the remark of lower implementation cost, fast and effective spanning tree reconnection mechanism can achieve better performance than other resilient technique for Metro Ethernet Network
Evolución conceptual de los protocolos de puentes transparentes
Los puentes Ethernet transparentes son un elemento cada vez más importante en las redes\ud
de telecomunicaciones. Este artículo ofrece una visión panorámica de la evolución conceptual de los\ud
paradigmas de puentes durante las últimas décadas, desde los puentes transparentes con árbol de\ud
expansión hasta las propuestas actualmente en estandarización: por una parte Shortest Path Bridges,\ud
Provider Bridges y Provider Backbone Bridges en el IEEE 802.1; por otra parte Routing Bridges en el\ud
IETF. Estas propuestas buscan aumentar la escalabilidad y obtener una alta utilización de la infraestructura\ud
de red, así como la provisión de servicios basados en Ethernet a gran número de usuarios. Mediante\ud
un mapa genealógico y una tabla se resumen e ilustran los aspectos funcionales, la evolución de los\ud
puentes propuestos en cuanto a los mecanismos básicos empleados para el encaminamiento, reenvío\ud
y la prevención de bucles tales como protocolos de vector distancia y de estado de enlaces, árboles\ud
múltiples de expansión, jerarquización mediante encapsulado de tramas y prohibición de algunos giros\ud
en los nodos. La evolución reciente de las propuestas muestra claramente varias tendencias: el predominio\ud
de los protocolos de estado de enlaces como IS-IS para el encaminamiento y/o construcción de\ud
árboles múltiples, de los mecanismos de encapsulado, y la multiplicación de tipos de identificadores\ud
para etiquetar y procesar separada y homogéneamente miles de servicios y clientes
Evolución conceptual de los protocolos de puentes transparentes
Los puentes Ethernet transparentes son un elemento cada vez más importante en las redes
de telecomunicaciones. Este artículo ofrece una visión panorámica de la evolución conceptual de los
paradigmas de puentes durante las últimas décadas, desde los puentes transparentes con árbol de
expansión hasta las propuestas actualmente en estandarización: por una parte Shortest Path Bridges,
Provider Bridges y Provider Backbone Bridges en el IEEE 802.1; por otra parte Routing Bridges en el
IETF. Estas propuestas buscan aumentar la escalabilidad y obtener una alta utilización de la infraestructura
de red, así como la provisión de servicios basados en Ethernet a gran número de usuarios. Mediante
un mapa genealógico y una tabla se resumen e ilustran los aspectos funcionales, la evolución de los
puentes propuestos en cuanto a los mecanismos básicos empleados para el encaminamiento, reenvío
y la prevención de bucles tales como protocolos de vector distancia y de estado de enlaces, árboles
múltiples de expansión, jerarquización mediante encapsulado de tramas y prohibición de algunos giros
en los nodos. La evolución reciente de las propuestas muestra claramente varias tendencias: el predominio
de los protocolos de estado de enlaces como IS-IS para el encaminamiento y/o construcción de
árboles múltiples, de los mecanismos de encapsulado, y la multiplicación de tipos de identificadores
para etiquetar y procesar separada y homogéneamente miles de servicios y clientes
Techniques d'ingénierie de trafic dynamique pour l'internet
Network convergence and new applications running on end-hosts result in increasingly variable and unpredictable traffic patterns. By providing origin-destination pairs with several possible paths, Dynamic Load-Balancing (DLB) has proved itself an excellent tool to face this uncertainty. The objective in DLB is to distribute traffic among these paths in real-time so that a certain objective function is optimized. In these dynamic schemes, paths are established a priori and the amount of traffic sent through each of them depends on the current traffic demand and network condition. In this thesis we study and propose various DLB mechanisms, differing in two important aspects. The first difference resides in the assumption, or not, that resources are reserved for each path. The second lies on the objective function, which clearly dictates the performance obtained from the network. However, a performance benchmarking of the possible choices has not been carried out so far. In this sense, for the case in which no reservations are performed, we study and compare several objective functions, including a proposal of ours. We will also propose and study a new distributed algorithm to attain the optimum of these objective functions. Its advantage with respect to previous proposals is its complete self-configuration (i. E. Convergence is guaranteed without any parametrization). Finally, we present the first complete comparative study between DLB and Robust Routing (a fixed routing configuration for all possible traffic demands). In particular, we analyze which scheme is more convenient in each given situation, and highlight some of their respective shortcomings and virtues.Avec la multiplication des services dans un même réseau et les diversités des applications utilisées par les usagers finaux, le trafic transporté est devenu très complexe et dynamique. Le Partage de la Charge Dynamique (PCD) constitue une alternative intéressante pour résoudre cette problématique. Si une paire Source-Destination est connectée par plusieurs chemins, le problème est le suivant : comment distribuer le trafic parmi ces chemins de telle façon qu’une fonction objective soit optimisé. Dans ce cas les chemins sont fixés a priori et la quantité de trafic acheminée sur chaque route est déterminée dynamiquement en fonction de la demande de trafic et de la situation actuelle du réseau. Dans cette thèse nous étudions puis nous proposons plusieurs mécanismes de PCD. Tout d'abord, nous distinguons deux types d’architecture : celles dans lesquelles les ressources sont réservées pour chaque chemin, et celles pour lesquelles aucune réservation n'est effectuée. La simplification faite dans le premier type d’architecture nous permet de proposer l'utilisation d'un nouveau mécanisme pour gérer les chemins. Partant de ce mécanisme, nous définissons un nouvel algorithme de PCD. Concernant la deuxième architecture, nous étudions et comparons plusieurs fonctions objectives. À partir de notre étude, nous proposons un nouvel algorithme distribué permettant d’atteindre l'optimum de ces fonctions objectives. La principale caractéristique de notre algorithme, et son avantage par rapport aux propositions antérieures, est sa capacité d'auto-configuration, dans la mesure où la convergence de l'algorithme est garantie sans aucun besoin de réglage préalable de ses paramètres
A survey of Virtual Private LAN Services (VPLS): Past, present and future
Virtual Private LAN services (VPLS) is a Layer 2 Virtual Private Network (L2VPN) service that has gained immense popularity due to a number of its features, such as protocol independence, multipoint-to-multipoint mesh connectivity, robust security, low operational cost (in terms of optimal resource utilization), and high scalability. In addition to the traditional VPLS architectures, novel VPLS solutions have been designed leveraging new emerging paradigms, such as Software Defined Networking (SDN) and Network Function Virtualization (NFV), to keep up with the increasing demand. These emerging solutions help in enhancing scalability, strengthening security, and optimizing resource utilization. This paper aims to conduct an in-depth survey of various VPLS architectures and highlight different characteristics through insightful comparisons. Moreover, the article discusses numerous technical aspects such as security, scalability, compatibility, tunnel management, operational issues, and complexity, along with the lessons learned. Finally, the paper outlines future research directions related to VPLS. To the best of our knowledge, this paper is the first to furnish a detailed survey of VPLS.University College DublinAcademy of Finlan
Fault diagnosis for IP-based network with real-time conditions
BACKGROUND:
Fault diagnosis techniques have been based on many paradigms, which derive from diverse areas
and have different purposes: obtaining a representation model of the network for fault localization,
selecting optimal probe sets for monitoring network devices, reducing fault detection time, and
detecting faulty components in the network. Although there are several solutions for diagnosing
network faults, there are still challenges to be faced: a fault diagnosis solution needs to always be
available and able enough to process data timely, because stale results inhibit the quality and speed
of informed decision-making. Also, there is no non-invasive technique to continuously diagnose the
network symptoms without leaving the system vulnerable to any failures, nor a resilient technique
to the network's dynamic changes, which can cause new failures with different symptoms.
AIMS:
This thesis aims to propose a model for the continuous and timely diagnosis of IP-based networks
faults, independent of the network structure, and based on data analytics techniques.
METHOD(S):
This research's point of departure was the hypothesis of a fault propagation phenomenon that
allows the observation of failure symptoms at a higher network level than the fault origin. Thus, for
the model's construction, monitoring data was collected from an extensive campus network in
which impact link failures were induced at different instants of time and with different duration.
These data correspond to widely used parameters in the actual management of a network. The
collected data allowed us to understand the faults' behavior and how they are manifested at a
peripheral level.
Based on this understanding and a data analytics process, the first three modules of our model,
named PALADIN, were proposed (Identify, Collection and Structuring), which define the data
collection peripherally and the necessary data pre-processing to obtain the description of the
network's state at a given moment. These modules give the model the ability to structure the data
considering the delays of the multiple responses that the network delivers to a single monitoring
probe and the multiple network interfaces that a peripheral device may have.
Thus, a structured data stream is obtained, and it is ready to be analyzed. For this analysis, it was
necessary to implement an incremental learning framework that respects networks' dynamic
nature. It comprises three elements, an incremental learning algorithm, a data rebalancing strategy,
and a concept drift detector. This framework is the fourth module of the PALADIN model named
Diagnosis.
In order to evaluate the PALADIN model, the Diagnosis module was implemented with 25 different
incremental algorithms, ADWIN as concept-drift detector and SMOTE (adapted to streaming scenario) as the rebalancing strategy. On the other hand, a dataset was built through the first
modules of the PALADIN model (SOFI dataset), which means that these data are the incoming data
stream of the Diagnosis module used to evaluate its performance.
The PALADIN Diagnosis module performs an online classification of network failures, so it is a
learning model that must be evaluated in a stream context. Prequential evaluation is the most used
method to perform this task, so we adopt this process to evaluate the model's performance over
time through several stream evaluation metrics.
RESULTS:
This research first evidences the phenomenon of impact fault propagation, making it possible to
detect fault symptoms at a monitored network's peripheral level. It translates into non-invasive
monitoring of the network. Second, the PALADIN model is the major contribution in the fault
detection context because it covers two aspects. An online learning model to continuously process
the network symptoms and detect internal failures. Moreover, the concept-drift detection and
rebalance data stream components which make resilience to dynamic network changes possible.
Third, it is well known that the amount of available real-world datasets for imbalanced stream
classification context is still too small. That number is further reduced for the networking context.
The SOFI dataset obtained with the first modules of the PALADIN model contributes to that number
and encourages works related to unbalanced data streams and those related to network fault
diagnosis.
CONCLUSIONS:
The proposed model contains the necessary elements for the continuous and timely diagnosis of IPbased
network faults; it introduces the idea of periodical monitorization of peripheral network
elements and uses data analytics techniques to process it. Based on the analysis, processing, and
classification of peripherally collected data, it can be concluded that PALADIN achieves the
objective. The results indicate that the peripheral monitorization allows diagnosing faults in the
internal network; besides, the diagnosis process needs an incremental learning process, conceptdrift
detection elements, and rebalancing strategy.
The results of the experiments showed that PALADIN makes it possible to learn from the network
manifestations and diagnose internal network failures. The latter was verified with 25 different
incremental algorithms, ADWIN as concept-drift detector and SMOTE (adapted to streaming
scenario) as the rebalancing strategy.
This research clearly illustrates that it is unnecessary to monitor all the internal network elements
to detect a network's failures; instead, it is enough to choose the peripheral elements to be
monitored. Furthermore, with proper processing of the collected status and traffic descriptors, it is
possible to learn from the arriving data using incremental learning in cooperation with data
rebalancing and concept drift approaches. This proposal continuously diagnoses the network
symptoms without leaving the system vulnerable to failures while being resilient to the network's
dynamic changes.Programa de Doctorado en Ciencia y Tecnología Informática por la Universidad Carlos III de MadridPresidente: José Manuel Molina López.- Secretario: Juan Carlos Dueñas López.- Vocal: Juan Manuel Corchado Rodrígue
- …