Alternative Multiple Spanning Tree Protocol (AMSTP) for Optical Ethernet Backbones

The availability and affordable cost of Gigabit and 10 Gigabit Ethernet switches has impacted the deployment of metropolitan area networks (MAN) and campus networks. This paper presents a new protocol, the alternative multiple spanning tree protocol (AMSTP), that uses multiple source based spanning trees for backbones using Ethernet switches. It provides minimum paths and more efficient usage of optical backbone infrastructure than currently proposed protocols such as resilient packet ring and rapid spanning tree. The protocol exhibits features similar to MAC routing protocols like Link State Over MAC (LSOM) such as optimum path and effective infrastructure usage, without requiring MAC routing due to the use of the spanning tree protocol paradigm. AMSTP is not restricted to specific topologies such as ring or tree, but performs efficiently in arbitrary topologies. Among the application areas are optical backbones of campus and MANs.Publicad

Fault Tolerant Scalable Support for Network Portability and Traffic Engineering

The P-SHIM6 architecture provides ISP independence to IPv6 sites without compromising scalability. This architecture is based on a middle-box, the P-SHIM6, which manages the SHIM6 protocol exchange on behalf of the nodes of a site, which are configured with provider independent addresses. Incoming and outgoing packets are processed by the P-SHIM6 box, which can assign different locators to a given communication, either when it is started, or dynamically after the communication has been established. As a consequence, changes required for provider portability are minimized, and fine-grained Traffic Engineering can be enforced at the P-SHIM6 box, in addition to the fault tolerance support provided by SHIM6.This project has been supported by the RiNG project IST-2005-035167 and by the IMPROVISA project TSI2005-07384-C03-02.Publicad

BGP-like TE Capabilities for SHIM6

In this paper we present a comprehensive set of mechanisms that restore to the site administrator the capacity of enforcing traffic engineering (TE) policies in a multiaddressed IPv6 scenario. The mechanisms rely on the ability of SHIM6 to securely perform locator changes in a transparent fashion to transport and application layers. Once an outgoing path has been selected for a communication by proper routing configuration in the site, the source prefix of SHIM6 data packets is rewritten by the site routers to avoid packet discarding due to ingress filtering. The SHIM6 locator preferences exchanged in the context establishment phase are modified by the site routers to influence in the path used for receiving traffic. Scalable deployment is ensured by the stateless nature of these mechanisms.Publicad

Fundamentos de Marketing 2013

1 archivo PDF (3 páginas). magyeffEsta reseña trata de la undécima edición, de "Fundamentos de marketing" publicada en 2013, de texto que sin duda es una referencia recurrente en la formación de administradores, mercadólogos y diseñadores, entre otros. ABSTRACT: This review is the eleventh edition published in 2013, a text which certainly is a recurring reference training administrators, marketers and designers, among others. PALABRAS CLAVE: Mercadotecnia. Consumidores. KEYWORDS: Marketing. Consumers

Exploring the Features to Classify the Musical Period of Western Classical Music

Music Information Retrieval (MIR) focuses on extracting meaningful information from music content. MIR is a growing field of research with many applications such as music recommendation systems, fingerprinting, query-by-humming or music genre classification. This study aims to classify the styles of Western classical music, as this has not been explored to a great extent by MIR. In particular, this research will evaluate the impact of different music characteristics on identifying the musical period of Baroque, Classical, Romantic and Modern. In order to easily extract features related to music theory, symbolic representation or music scores were used, instead of audio format. A collection of 870 Western classical music piano scores was downloaded from different sources such as KernScore library (humdrum format) or the Musescore community (MusicXML format). Several global features were constructed by parsing the files and accessing the symbolic information, including notes and duration. These features include melodic intervals, chord types, pitch and rhythm histograms and were based on previous studies and music theory research. Using a radial kernel support vector machine algorithm, different classification models were created to analyse the contribution of the main musical properties: rhythm, pitch, harmony and melody. The study findings revealed that the harmony features were significant predictors of the music styles. The research also confirmed that the musical styles evolved gradually and that the changes in the tonal system through the years, appeared to be the most significant change to identify the styles. This is consistent with the findings of other researchers. The overall accuracy of the model using all the available features achieved an accuracy of 84.3%. It was found that of the four periods studied, it was most difficult to classify music from the Modern period

An Architecture for Network Layer Privacy

We present an architecture for the provision of network layer privacy based on the SHIM6 multihoming protocol. In its basic form, the architecture prevents on-path eavesdroppers from using SHIM6 network layer information to correlate packets that belong to the same communication but use different locators. To achieve this, several extensions to the SHIM6 protocol and to the HBA (Hash Based Addresses) addressing model are defined. On its full-featured mode of operation, hosts can vary dynamically the addresses of the packets of on-going communications. Single-homed hosts can adopt the SHIM6 protocol with the privacy enhancements to benefit from this protection against information collectors.IEEE Communications SocietyPublicad

Efficient security for IPv6 multihoming

In this note, we propose a security mechanism for protecting IPv6 networks from possible abuses caused by the malicious usage of a multihoming protocol. In the presented approach, each multihomed node is assigned multiple prefixes from its upstream providers, and it creates the interface identifier part of its addresses by incorporating a cryptographic one-way hash of the available prefix set. The result is that the addresses of each multihomed node form an unalterable set of intrinsically bound IPv6 addresses. This allows any node that is communicating with the multihomed node to securely verify that all the alternative addresses proposed through the multihoming protocol are associated to the address used for establishing the communication. The verification process is extremely efficient because it only involves hash operationsPublicad

IPv6 Multihoming Support in the Mobile Internet

Fourth-generation mobile devices incorporate multiple interfaces with diverse access technologies. The current Mobile IPv6 protocol fails to support the enhanced fault tolerance capabilities that are enabled by the availability of multiple interfaces. In particular, established MIPv6 communications cannot be preserved through outages affecting the home address. In this article, we describe an architecture for IPv6 mobile host multihoming that enables transport layer survivability through multiple failure modes. The proposed approach relies on the cooperation between the MIPv6 and the SHIM6 protocols.Publicad

Analysis from hiring process formulation maintenance and construction from army prosecutors houses including environmental parameters

Este artículo se enfoca en analizar la formulación de procesos de contratación de mantenimiento y construcción de vivienda fiscal mediante la inclusión de parámetros ambientales. Presentando una revisión del marco normativo existente para la contratación en el sector público, logrando identificar códigos, leyes y normas que orientan sobre los aspectos que deben incluirse en los contratos entre el Estado y los contratistas. Considerando los aspectos relacionados con compras eficientes por parte del estado se efectúa una revisión del enfoque europeo en la Compra y Contratación Pública Verde y, para el caso colombiano la existencia de guías verdes de contratación. Teniendo en cuenta criterios ambientales asociados a la construcción se establece la posibilidad de incluir dichos aspectos en diferentes fases del proceso de contratación estatal promoviendo de manera efectiva una compra eficiente en lo relacionado con proyectos de construcción y mantenimiento de vivienda que desarrolla el Instituto de Casas Fiscales del Ejército.This article analyze the development of procurement processes maintenance and construction of housing tax by including environmental parameters. Presents a review of the existing regulatory framework for recruitment in the public sector, codes, laws and regulations that provide guidance on the issues to be included in contracts between the state and contractors are identified. Considering the aspects of efficient purchases by the state carries out a review of the European focus on Green Public Procurement, for the Colombian case the existence of green procurement guidelines. Given associated with building environmental criteria the possibility to include these aspects in different stages of government procurement to promote effectively an efficient purchase in relation to construction projects and maintenance of housing developed by the Institute of Army Prosecutors Houses

Traffic engineering in multihomed sites

It is expected that IPv6 multihomed sites will obtain as many global prefixes as direct providers they have, so traffic engineering techniques currently used in IPv4 multihomed sites is no longer suitable. However, traffic engineering is required for several reasons, and in particular, for being able to properly support multimedia communications. In this paper we present a framework for traffic engineering in IPv6 multihomed sites with multiple global prefixes. Within this framework, we have included several tools such as DNS record manipulation and proper configuration of the policy table defined in RFC 3484. To provide automation in the management of traffic engineering, we analyzed the usage of two mechanisms to configure the policy table.This work has been partly supported by the European Union under the E-Next Project FP6-506869 and by the OPTINET6 project TIC-2003-09042-C03-01.Publicad