256,111 research outputs found
IP-layer soft handoff implementation in ILNP
No full textDate of Acceptance: 14/07/2014We present the first results of an implementation of IP-layer soft handoff, based on the Identifier Locator Network Protocol (ILNP). In our testbed experiments, we show minimal gratuitous packet loss in vertical handoff scenarios (WiFi-3G). Unlike the IETF Mobile IP proposals, the ILNP uses a purely end-to-end architecture, and does not require proxies, middleboxes or tunnelling to support mobility. Our testbed is based on an in-kernel implementation using a modified Linux IP stack
An IP-ERN architecture to enable hybrid E2E/ERN protocol and application to satellite networking
No full textWe propose an architecture based on a hybrid E2E-ERN approach allowing ERN protocols to be inter-operable with current IP-based networks. Without introducing complex operations, the resulting E2E-ERN protocol provides inter and intra protocol fairness and benefits from all ERN advantages when possible. We detail the principle of this novel architecture, called IP-ERN, and show that this architecture is highly adaptive to the network dynamics and is compliant with every TCP feature, IPv4, IPv6 as well as IP-in-IP tunneling solutions. As a possible use case, we test this architecture as a potential candidate to replace Performance Enhancing Proxies (PEPs) commonly-used over satellite IP-based networks. Compared to splitting PEP, the IP-ERN architecture does not break the E2E connectivity, still achieves high satellite link utilization and fairness without needs of extra fault tolerant mechanism
IP-for-IP or Cash-for-IP? R&D Competition and the Market for Technology
No full textThis paper argues that firms use 'IP-for-IP' policies such as cross-licensing to strategically restrict transactions in the market for technology. The commitment to limit trade to reciprocal exchange (barter instead of cash transactions) enables firms to alter the allocation of R&D and soften R&D competition. In particular, it induces firms to focus R&D on their area of expertise. The costs of IP-for-IP are foregone gains from trade. Our analysis of the trade-offs involved shows that IP-for-IP is profitable in industries where firms differ in their capabilities to commercialize IP. Patent complementarities and firm asymmetries further strengthen the optimality of IP-for-IP
Avaliação das propostas de integração IP sobre ATM
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Ciência da Computação.ATM (Asynchronous Transfer Mode) é uma das tecnologias de rede de alta velocidade mais adotada nos dias atuais, sendo que um dos principais diferenciais desta tecnologia é o provimento de Qualidade de Serviço. Atualmente, a tecnologia ATM deve conviver com o protocolo IP, devido principalmente ao grande volume de aplicações. Existem algumas alternativas em termos de integração do IP com ATM, por exemplo IPOA (Internet Protocol Over ATM), LANE (Lan Emulation), MPOA (MultProtocol Over ATM) e MPLS (MultProtocol Label Switch). Este trabalho apresenta estas propostas de integração IP sobre ATM, fazendo também uma análise comparativa. Outra contribuição deste trabalho é a definição de linhas guias para a seleção de uma destas opções de integração de IP sobre ATM durante o projeto de uma rede
Sistema de monitoramento de qualidade em serviços de telefonia IP
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Ciência da Computação, Florianópolis, 2015.A telefonia IP é um serviço consolidado que tem crescido de forma constante, impulsionada por suas diversas vantagens, como redução de custos, facilidade de integração com outros serviços, dentre muitas outras. No entanto, manter a qualidade deste serviço ainda é um desafio principalmente em locais de redes congestionadas. Como a telefonia é um serviço essencial para várias organizações, é fundamental manter as chamadas em níveis razoáveis de qualidade. Para tal, a qualidade oferecida pela telefonia IP deve ser constantemente monitorada de maneira a orientar as ações de novos investimentos e manutenção. Nesta direção, a presente dissertação propõe um sistema de monitoramento da qualidade fim-a-fim para os serviços de telefonia IP com base no pacote de relatórios de qualidade RTCP XR (Real Time Control Protocol - Extended Reports) e no protocolo de sinalização SIP (Session Initiation Protocol). Um caso de uso do sistema proposto, em um serviço de produção de telefonia IP de uma universidade, utilizando métricas objetivas e metodologias de monitoramento não intrusivas, demonstrou a efetividade e versatilidade do sistema proposto.Abstract : IP telephony is a consolidated service that has been growing steadily, driven by its various advantages, such as cost reduction, ease of integration with other services, among many others. However, maintaining the quality of this service is still a challenge especially in places of congested networks. As the telephony is an essential service for various organizations, it is essential to maintain the call quality at reasonable levels. To this end, the quality offered by IP telephony should be constantly monitored in order to guide the actions of new investments and maintenance. In this direction, this thesis proposes a quality end-to-end monitoring system for IP telephony services based on quality reporting package RTCP XR (Real Time Control Protocol - Extended Reports) and SIP signaling protocol (Session Initiation Protocol). A use case of the proposed system in an IP telephony production service of a university, using objective metrics and non-intrusive monitoring methodologies, demonstrated the effectiveness and versatility of the proposed system
The diffusion of IP telephony and vendors' commercialisation strategies
No full textThis is a post-peer-review, pre-copyedit version of an article published in the Journal of Information Technology. The definitive publisher-authenticated version is available at the link below.The Internet telephony (IP telephony) has been presented as a technology that can replace existing fixed-line services and disrupt the telecommunications industry by offering new low-priced services. This study investigates the diffusion of IP telephony in Denmark by focusing on vendors’ commercialisation strategies. The theory of disruptive innovation is introduced to investigate vendors’ perceptions about IP telephony and explore their strategies that affect the diffusion process in the residential market. The analysis is based on interview data collected from the key market players. The study's findings suggest that IP telephony is treated as a sustaining innovation that goes beyond the typical voice transmission and enables provision of advanced services such as video telephony
Economic Development Potential through IP Telephony for Namibia
No full textIP telephony, economic growth, telecommunications, ICT, Granger causality, Namibia
A survey of requirements and standardization efforts for IP-telephony-security
No full textSecurity as a dimension of trustworthiness in IP-Telephony systems and protocols is a main condition for the commercial success of IP-Telephony. In this work, we present a survey of security requirements and show how various standardization efforts address these requirements. We describe the basic tasks and elements of IP-Telephony systems and compare them to Telephony via PSTNs to derive some possible attacks for example. We classify the security preconditions to achieve trustworthiness of users and providers in this systems. We list weighty criteria for further evaluation of security mechanisms which can fulfil these requirements. After this, we describe the integration of security mechanisms in current IP-Telephony protocols and figure out work areas which have to be solved in future
Multimedia session continuity in the IP multimedia subsystem : investigation and testbed implementation
No full textIncludes bibliographical references (leaves 91-94).The advent of Internet Protocol (IP) based rich multimedia services and applications has seen rapid growth and adoption in recent years, with an equally increasing user base. Voice over IP (VoIP) and IP Television (IPTV) are key examples of services that are blurring the lines between traditional stove-pipe approach network infrastructures. In these, each service required a different network technology to be provisioned, and could only be accessed through a specific end user equipment (UE) technology. The move towards an all-IP core network infrastructure and the proliferation of multi-capability multi-interface user devices has spurred a convergence trend characterized by access to services and applications through any network, any device and anywhere
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