22 research outputs found

    Multicast Mobility in Mobile IP Version 6 (MIPv6) : Problem Statement and Brief Survey

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    An approach to enhance aggregated source specific multicast scheme

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    The Aggregated Source Specific Multicast (ASSM) scheme is proposed to overcome the limitations of Source Specific Multicast (SSM). It aims to handle the scalability issue of SSM. The key idea is that multiple groups are forced to share a single delivery tree. However, the ASSM scheme suffers from routers under utilization problem. In our previous work we have proposed an approach to overcome this problem. In this paper our proposed approach was presented and evaluated. It was shown that our proposed scheme results in achieving higher routers utilization

    Yodel: A Layer 3.5 Name-Based Multicast Network Architecture For The Future Internet

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    Multicasting refers to the ability of transmitting data to multiple recipients without data sources needing to provide more than one copy of the data to the network. The network takes responsibility to route and deliver a copy of each data to every intended recipient. Multicasting has the potential to improve the network efficiency and performance (e.g., throughput and latency) through transferring fewer bits in communicating the same data to multiple recipients compared with unicast transmissions, reduce the amount of networking resources needed for communication, lower the network energy footprint, and alleviate the occurrence of congestion in the network. Over the past few decades, providing multicast services has been a real challenge for ISPs, especially to support home users and multi-domain network applications, leading to the emergence of complex application-level solutions. These solutions like Content Delivery and Peer-to-Peer networks take advantage of complex caching, routing, transport, and topology management systems which put heavy strains on the underlying Internet infrastructures to offer multicasting services. In reality, the main motivation behind the design of these systems is rather sharing content than offering efficient multicast services. In this paper, we propound Yodel, a name-based multicast network architecture that can provide multi-domain multicast services for current and future Internet applications. Compared to the wider array of other name-based network architectures with clean-slate infrastructure requirements, Yodel is designed to provide multicast services over the current Internet infrastructure. Hence, Yodel puts forward several design goals that distinguish it from other name-based network architectures with inherent multicast capabilities. This paper is prepared to discuss the Yodel architecture, its design goals, and architectural functions.Comment: Contains animated figure

    Optimização de recursos para difusão em redes de próxima geração

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    Doutoramento em ElectrotecniaEsta tese aborda o problema de optimização de recursos de rede, na entrega de Serviços de Comunicação em Grupo, em Redes de Próxima Geração que suportem tecnologias de difusão. De acordo com esta problemática, são feitas propostas que levam em atenção a evolução espectável das redes 3G em Redes Heterogéneas de Próxima Geração que incluam tecnologias de difusão tais como o DVB. A optimização de recursos em Comunicações em Grupo é apresentada como um desafio vertical que deve cruzar diversas camadas. As optimizações aqui propostas cobrem tanto a interface entre Aplicação e a Plataforma de Serviços para a disponibilização de serviços de comunicação em grupo, como as abstracções e mapeamentos feitos na interface entre a Rede Central e a Rede de Acesso Rádio. As optimizações propostas nesta tese, assumem que o caminho evolutivo na direcção de uma Rede de Próxima Geração é feito através do IP. Em primeiro lugar são endereçadas as optimizações entre a Aplicação e a Plataforma de Serviços que já podem ser integradas nas redes 3G existentes. Estas optimizações podem potenciar o desenvolvimento de novas e inovadoras aplicações, que através do uso de mecanismos de distribuição em difusão podem fazer um uso mais eficiente dos recursos de rede. De seguida são apresentadas optimizações ao nível da interface entre a Rede Central e a Rede de Acesso Rádio que abordam a heterogeneidade das redes futuras assim como a necessidade de suportar tecnologias de difusão. É ainda considerada a possibilidade de aumentar a qualidade de serviço de serviços de difusão através do mapeamento do IP multicast em portadoras unidireccionais. Por forma a validar todas estas optimizações, vários protótipos foram desenvolvidos com base num router avançado para redes de acesso de próxima geração. As funcionalidades e arquitectura de software desse router são também aqui apresentadas.This thesis addresses the problem of optimizing network resource usage, for the delivery of Group Services, in Next Generation Networks featuring broadcast technologies. In this scope, proposals are made according to the expected evolution of 3G networks into Next Generation Heterogeneous Networks that include broadcast technologies such as DVB. Group Communication resource optimization is considered a vertical challenge that must cross several layers. The optimizations here proposed cover both Application to Service Platform interfaces for group communication services, and Core Network to Radio Access Network interface abstractions and mappings. The proposed optimizations are also presented taking into consideration network evolution path towards an All-IP based Next Generation Network. First it is addressed the Application to Service Platform optimization, which can already be deployed over 3G networks. This optimization could potentiate the development of new and innovative applications that through the use of broadcast/multicast service delivery mechanisms could be more efficient network wise. Next proposals are made on the Core Network to Radio Access Network interfaces that address the heterogeneity of future networks and consider the need to support broadcast networks. It is also considered the possibility to increase the Quality of Service of broadcast/multicast services based on the dynamic mapping of IP multicast into unicast radio bearers. In order to validate these optimizations, several prototypes were built based on an advanced access router for next generation networks. Such access router functionalities and software architecture are also presented here

    Internet-of-Things Streaming over Realtime Transport Protocol : A reusablility-oriented approach to enable IoT Streaming

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    The Internet of Things (IoT) as a group of technologies is gaining momentum to become a prominent factor for novel applications. The existence of high computing capability and the vast amount of IoT devices can be observed in the market today. However, transport protocols are also required to bridge these two advantages. This thesis discussed the delivery of IoT through the lens of a few selected streaming protocols, which are Realtime Transport Protocol(RTP) and its cooperatives like RTP Control Protocol(RTCP) and Session Initiation Protocol (SIP). These protocols support multimedia content transfer with a heavy-stream characteristic requirement. The main contribution of this work was the multi-layer reusability schema for IoT streaming over RTP. IoT streaming as a new concept was defined, and its characteristics were introduced to clarify its requirements. After that, the RTP stacks and their commercial implementation-VoLTE(Voice over LTE) were investigated to collect technical insights. Based on this distilled knowledge, the application areas for IoT usage and the adopting methods were described. In addition to the realization, prototypes were made to be a proof of concept for streaming IoT data with RTP functionalities on distanced devices. These prototypes proved the possibility of applying the same duo-plane architect (signaling/data transferring) widely used in RTP implementation for multimedia services. Following a standard IETF, this implementation is a minimal example of adopting an existing standard for IoT streaming applications

    Multicast for ubiquitos streaming of multimedia content to mobile terminals : Network architecture and protocols

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    The Universal Mobile Telecommunication Services (UMTS) network was envisioned to carry a wide range of new services; however, the first UMTS release was not designed to efficiently support multimedia content. In this thesis we analyse several mechanisms, and suggest architectural changes to improve UMTS’s capacity for a subset of the multimedia services; high-bandwidth group services. In our initial work we have suggested how IP multicast protocols can be used in the UMTS network to reduce the required network capacity for group services. This proposal was one of many suggestions for the evolving Multimedia Broadcast/Multicast Service (MBMS) architecture for UMTS. The next technique we have suggested and analysed is a new wireless channel type named the "sticky-channel"; this channel is intended for sparsely populated multicast groups. The sticky-channel is able to stick to mobile multicast members in the boarder area of neighbouring radio cells, thus some base stations does not need to broadcast the multicast data. Consequently, the total number of broadcast channels needed to cover a given area is reduced. There is a marginal reduction of required resources with this technique. In the main part of our work we have studied heterogeneous multihop wireless access for multicast traffic in the UMTS network. In a heterogeneous wireless access network, the wireless resources needed to distribute high-bandwidth group services, can be shared among cooperating network technologies. Mobile terminals with a UMTS interface and an IEEE 802.11 interface are readily available, consequently a heterogeneous network with UMTS and 802.11 links will be easy to deploy. We have described a heterogeneous architecture based on those wireless technologies. In this architecture, the range of a UMTS radio channel is reduced, and local IEEE 802.11-based Mobile Ad Hoc Networks (MANETs) forward the data to users located outside the coverage of the reduced UMTS channel. The wireless resources required to transmit a data packet are proportional to (at least) the square of the distance the packet must travel, thus a reduction in the channel range releases a significant amount of UMTS radio resources. Detailed simulation results showed acceptable service quality when the UMTS broadcast channel range is more than halved. Finally we have studied whether Forward Error Correction (FEC) at the packet-level on multicast flows could improve the performance of the heterogeneous wireless access network. There is a marginal improvement. Most of the protection brought by the FEC code has been used to repair the increased packet-loss introduced by the FEC overhead

    Distribuição de vídeo para grupos de utilizadores em redes móveis heterogéneas19

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    The evolutions veri ed in mobile devices capabilities (storage capacity, screen resolution, processor, etc.) over the last years led to a signi cant change in mobile user behavior, with the consumption and creation of multimedia content becoming more common, in particular video tra c. Consequently, mobile operator networks, despite being the target of architectural evolutions and improvements over several parameters (such as capacity, transmission and reception performance, amongst others), also increasingly become more frequently challenged by performance aspects associated to the nature of video tra c, whether by the demanding requirements associated to that service, or by its volume increase in such networks. This Thesis proposes modi cations to the mobile architecture towards a more e cient video broadcasting, de ning and developing mechanisms applicable to the network, or to the mobile terminal. Particularly, heterogeneous networks multicast IP mobility supported scenarios are focused, emphasizing their application over di erent access technologies. The suggested changes are applicable to mobile or static user scenarios, whether it performs the role of receiver or source of the video tra c. Similarly, the de ned mechanisms propose solutions targeting operators with di erent video broadcasting goals, or whose networks have di erent characteristics. The pursued methodology combined an experimental evaluation executed over physical testbeds, with the mathematical evaluation using network simulation, allowing the veri cation of its impact on the optimization of video reception in mobile terminalsA evolução veri cada nas características dos dispositivos moveis (capacidade de armazenamento, resolução do ecrã, processador, etc.) durante os últimos anos levou a uma alteração signi cativa nos comportamentos dos utilizadores, sendo agora comum o consumo e produção de conteúdos multimédia envolvendo terminais móveis, em particular o tráfego vídeo. Consequentemente, as redes de operador móvel, embora tendo também sido alvo constante de evoluções arquitecturais e melhorias em vários parâmetros (tais como capacidade, ritmo de transmissão/recepção, entre outros), vêemse cada vez mais frequentemente desa adas por aspectos de desempenho associados à natureza do tráfego de vídeo, seja pela exigência de requisitos associados a esse serviço, quer pelo aumento do volume do mesmo nesse tipo de redes. Esta Tese propôe alterações à arquitetura móvel para a disseminação de vídeo mais e ciente, de nindo e desenvolvendo mecanismos aplicáveis à rede, ou ao utilizador móvel. Em particular, são focados cenários suportados por IP multicast em redes móveis heterogéneas, isto é, com ênfase na aplicação destes mecanismos sobre diferentes tecnologias de acesso. As alterações sugeridas aplicam-se a cenários de utilizador estático ou móvel, sendo este a fonte ou receptor do tráfego vídeo. Da mesma forma, são propostas soluções tendo em vista operadores com diferentes objectivos de disseminação de vídeo, ou cujas redes têm diferentes características. A metodologia utilizada combinou a avaliação experimental em testbeds físicas com a avaliação matemática em simulações de redes, e permitiu veri car o impacto sobre a optimização da recepção de vídeo em terminais móveisPrograma Doutoral em Telecomunicaçõe

    Development of an adaptable multicast overlay network

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    Dissertação de mestrado em Informatics EngineeringMulticast is a group communication paradigm created in order to reduce, as much as possible, the amount of data generated to the network. However, limited deployment of IP Multicast protocols has motivated an interest in alternative approaches which implement a similar process of Multicast at an application-level (using solely end-systems and not the routers). In this context, different methodologies are presented, entitled Application-Layer Multicast or Overlay Multicast, which may vary in the way they operate. This dissertation’s objective is to develop and experiment a prototype of an overlay multicast system. This system should be easily configurable and adaptable in order to assume different strategies when establishing the multicast distribution tree. It is also expected to explore and integrate collaborative mechanisms between the overlay network and the Internet Service Providers (ISP). With the presented context, the first step to take is an investigation on the state of the art, where technologies relevant to this work will be presented. After this initial step, the developed system’s architecture will be described, one which enables different ways of building and maintaining the multicast distribution tree. The envisioned system can operate independently, integrating mechanisms where the distribution tree relies solely on peer decisions, which will be firstly addressed. Then, this work will move on to collaborative mechanisms between the overlay’s management (the central node) and the Internet Service Providers. Based on the proposed system architecture, several mechanisms are explored, not only focusing on alternative ways to build distribution trees, but also mechanisms allowing for some traffic engineering objectives involving the Internet Service Providers. Using the CORE network emulator, all the proposed mechanisms are tested, and results are analyzed to corroborate the system’s correct operation.O multicast é um paradigma de comunicação em grupo que tem como objetivo reduzir, tanto quanto possível, a quantidade de tráfego gerada para a rede. No entanto, a implantação limitada de protocolos IP Multicast tem motivado o interesse em abordagens alternativas que implementam processos de distribuição Multicast na camada aplicacional (ou seja, usando apenas os sistemas/aplicações finais e não os routers). Neste contexto, surgem as soluções denominadas por Application-Layer Multicast ou Overlay Multicast, podendo estas apresentar algumas variantes na sua operação. Nesta dissertação, tem-se como objetivo o desenvolvimento e experimentação de um protótipo de um sistema de Overlay Multicast. Este sistema deverá ser capaz de ser facilmente (re)configurado para assumir diferentes estratégias no estabelecimento da árvore de distribuição Multicast, e integrar mecanismos de colaboração entre a rede Overlay e os Internet Service Providers. No contexto apresentado, o primeiro passo consiste na investigação do estado da arte, onde tecnologias relevantes ao atual trabalho serão apresentadas. Após este passo inicial, a arquitectura do sistema será apresentada, uma arquitectura que considera diferentes maneiras de construir e manter a árvore de distribuição multicast. O sistema proposto pode operar de forma independente, contemplando mecanismos onde a árvore de distribuição depende apenas das decisões dos vários peers, sendo que estes serão os primeiros mecanismos a serem apresentados. De seguida, o sistema direcciona-se para mecanismos colaborativos entre a gestão da rede overlay e o ISP, de maneira a incluir conhecimento acerca da topologia da rede que nenhuma outra entidade seria capaz de providenciar. Com base na arquitectura do sistema proposto, vários mecanismos são explorados, não só mecanismos que se concentram em formas alternativas de construir a árvore de distribuição, mas também mecanismos que permitem cumprir os objetivos de engenharia de tráfico dos ISPs. Por fim, utilizando o emulador de redes CORE, todas as soluções serão testadas, e os seus resultados analisados por forma a validar a correta operação de todo o sistema
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