Exploiting the power of multiplicity: a holistic survey of network-layer multipath

The Internet is inherently a multipath network: For an underlying network with only a single path, connecting various nodes would have been debilitatingly fragile. Unfortunately, traditional Internet technologies have been designed around the restrictive assumption of a single working path between a source and a destination. The lack of native multipath support constrains network performance even as the underlying network is richly connected and has redundant multiple paths. Computer networks can exploit the power of multiplicity, through which a diverse collection of paths is resource pooled as a single resource, to unlock the inherent redundancy of the Internet. This opens up a new vista of opportunities, promising increased throughput (through concurrent usage of multiple paths) and increased reliability and fault tolerance (through the use of multiple paths in backup/redundant arrangements). There are many emerging trends in networking that signify that the Internet's future will be multipath, including the use of multipath technology in data center computing; the ready availability of multiple heterogeneous radio interfaces in wireless (such as Wi-Fi and cellular) in wireless devices; ubiquity of mobile devices that are multihomed with heterogeneous access networks; and the development and standardization of multipath transport protocols such as multipath TCP. The aim of this paper is to provide a comprehensive survey of the literature on network-layer multipath solutions. We will present a detailed investigation of two important design issues, namely, the control plane problem of how to compute and select the routes and the data plane problem of how to split the flow on the computed paths. The main contribution of this paper is a systematic articulation of the main design issues in network-layer multipath routing along with a broad-ranging survey of the vast literature on network-layer multipathing. We also highlight open issues and identify directions for future work

Multiple streaming at the network edge

Streaming video over the Internet, including cellular networks, has now become commonplace. Network operators typically use multicasting or variations of multiple unicasting to deliver streams to the user terminal in a controlled fashion. An emerging alternative is P2P streaming, which is theoretically more scalable but suffers from other issues arising from the dynamic nature of the system. User’s terminals become streaming nodes but these are not constantly connected. Another issue is that they are based on logical overlays, which are not optimized for the physical underlay infrastructure. An important proposition is that of finding effective ways to increase the resilience of the overlay whilst at the same time not conflicting with the network. In this article we look at the combination of two techniques, multi-streaming (redundancy) and locality (network efficiency) in the context of both live and video-on-demand streaming. We introduce a new technique and assess it via a comparative, simulation-based study. We find that redundancy affects network utilization only marginally if traffic is kept at the edges via localization technique

Towards video streaming in IoT environments: vehicular communication perspective

Multimedia oriented Internet of Things (IoT) enables pervasive and real-time communication of video, audio and image data among devices in an immediate surroundings. Today's vehicles have the capability of supporting real time multimedia acquisition. Vehicles with high illuminating infrared cameras and customized sensors can communicate with other on-road devices using dedicated short-range communication (DSRC) and 5G enabled communication technologies. Real time incidence of both urban and highway vehicular traffic environment can be captured and transmitted using vehicle-to-vehicle and vehicle-to-infrastructure communication modes. Video streaming in vehicular IoT (VSV-IoT) environments is in growing stage with several challenges that need to be addressed ranging from limited resources in IoT devices, intermittent connection in vehicular networks, heterogeneous devices, dynamism and scalability in video encoding, bandwidth underutilization in video delivery, and attaining application-precise quality of service in video streaming. In this context, this paper presents a comprehensive review on video streaming in IoT environments focusing on vehicular communication perspective. Specifically, significance of video streaming in vehicular IoT environments is highlighted focusing on integration of vehicular communication with 5G enabled IoT technologies, and smart city oriented application areas for VSV-IoT. A taxonomy is presented for the classification of related literature on video streaming in vehicular network environments. Following the taxonomy, critical review of literature is performed focusing on major functional model, strengths and weaknesses. Metrics for video streaming in vehicular IoT environments are derived and comparatively analyzed in terms of their usage and evaluation capabilities. Open research challenges in VSV-IoT are identified as future directions of research in the area. The survey would benefit both IoT and vehicle industry practitioners and researchers, in terms of augmenting understanding of vehicular video streaming and its IoT related trends and issues

Localized Multistreams for P2P Streaming

Streaming video over the Internet, including cellular networks, has now become a commonplace. Network operators typically use multicasting or variants of multiple unicasting to deliver streams to the user terminal in a controlled fashion. P2P streaming is an emerging alternative, which is theoretically more scalable but suffers from other issues arising from the dynamic nature of the system. Users' terminals become streaming nodes but they are not constantly connected. Another issue is that they are based on logical overlays, which are not optimized for the physical underlay infrastructure. An important proposition is to find effective ways to increase the resilience of the overlay whilst at the same time not conflicting with the network. In this article we look at the combination of two techniques, redundant streaming and locality awareness, in the context of both live and video-on-demand streaming. We introduce a new technique and assess it via a comparative, simulation-based study. We find that redundancy affects network utilization only marginally if traffic is kept at the edges via localization techniques

Mobile Ad-Hoc Networks

Being infrastructure-less and without central administration control, wireless ad-hoc networking is playing a more and more important role in extending the coverage of traditional wireless infrastructure (cellular networks, wireless LAN, etc). This book includes state-of-the-art techniques and solutions for wireless ad-hoc networks. It focuses on the following topics in ad-hoc networks: quality-of-service and video communication, routing protocol and cross-layer design. A few interesting problems about security and delay-tolerant networks are also discussed. This book is targeted to provide network engineers and researchers with design guidelines for large scale wireless ad hoc networks

Session Management in Multicast

As a new network technique to efficiently distribute information from a small number of senders to large numbers of receivers, multicast encounters many problems in scalability, membership management, security, etc. These problems hinder the deployment of multicast technology in commercial applications. To overcome these problems, a more general solution for multicast technology is needed. In this paper, after studying current multicast technologies, we summarized the technical requirements for multicast, including data delivery, scalability, security, group management, reliability, and deployment. In order to understand and meet the requirements, we define a life cycle model that most multicast sessions should follow. According to the requirements and the life cycle model, we propose and design a general solution that can control each phase of a session and satisfy most requirements for multicast technology. This general solution has three parts: hierarchical topology auto-configuration algorithm, Session Management Mechanism, and techniques supporting different multicast protocols. To verify the feasibility of our solution and compare its performance with other multicast techniques, we simulate our solution and compare it with PIM-SM and ESM

Topologías para la distribución de contenidos en redes de comunicación

The peer-to-peer (P2P) overlay networks are distribution topologies that take advantage of the ability that their nodes have to forward the information that they receive. For the particular case of video transmission using P2P networks, known as streaming P2P, there are implementations based on BitTorrent protocol data dissemination for files downloading. These networks use a pseudorandom topology which makes difficult to determine both the size of the network -defined as the maximum number of nodes which can receive information with a given quality of service- and the distribution delay. Despite this lack of definition, in the current thesis we present a structured network in which the nodes establish both incoming and outgoing connections according to a deterministic joining algorithm. That topology allows to calculate exactly the number of nodes that may join the network and that in stable conditions may get the flow with guaranteed quality of service, and also one very fitted bound for the total distribution delay. In our case, we have defined networks which contain a single source node with a bandwidth weater than the bandwidth of the information flow, and also a set of nodes with a bandwidth lower than the bandwidth of the flow. This constraint is used to distinguish the high capacity nodes from the terminal nodes which either have physical limitations due to their access link bandwidth or do not consider to allocate all their bandwidth to the forwarding of the information flow. In fact, high capacity nodes can be considered sources either because they produce the flow physically or because, receiving it from another distribution network, they forward it as source to the low bandwidth nodes that belong to the P2P network. Once the distribution topology is described, we define the mathematical model for its analysis. With this purpose, we normalize the flow bandwidth and we define a network joining algorithm with the aim of optimizing distribution delay. Following, the network topology is characterized by means of three parameters: the number of nodes that can be served directly by the source, the number of download connections that must arrive to a node to guarantee the reception at unitary rate, and the maximum number of upload connections that a node can establish. Likewise, the information flow is segmented into generic information units called objects, which are transmitted into the network by means of a certain set of dissemination trees. The number of dissemination trees corresponds to the number of download connections of a node. With this background material, we calculate the maximum number of peers which can be connected, under stable conditions, to the network, and also a very fitted bound for the transmission delay. Besides, we present a simulation that allows to evaluate the performance of the described topology in the field of VANET networks. Finally, in the last chapter we present a proposal for application-layer multicast distribution network which can be used to send the information flow from the node that initially produces it to the source nodes of the P2P distribution network that we have described.Las redes superpuestas peer-to-peer (P2P) son topologías de distribución que aprovechan la capacidad que tienen sus nodos de retransmitir a otros nodos la información que reciben. En el caso particular de la transmisión de vídeo mediante redes P2P, conocida como streaming P2P, existen implementaciones basadas en la diseminación de datos del protocolo BitTorrent de descarga de ficheros. Estas redes emplean una topología pseudoaletoria que hace difícilmente caracterizable tanto el tamaño que puede tener la red -entendido como el máximo número de nodos a los que se puede garantizar una calidad de servicio determinada- como el retardo de distribución. Frente a esta falta de definición, en el presente trabajo se presenta una red estructurada en la que los nodos establecen conexiones tanto de recepción como de retransmisión según un algoritmo de ingreso determinista. Dicha topología permite calcular exactamente el número máximo de nodos que pueden formar la red y que, en condiciones de estabilidad, reciben el flujo con garantías de calidad, así como una cota muy ajustada del retardo total de distribución. En nuestro caso, hemos definido redes formadas por un único nodo fuente con una capacidad mayor que el ancho de banda de la transmisión del flujo, así como por una serie de nodos cuya capacidad es inferior al ancho de banda de dicho flujo. Esta restricción sirve para separar los nodos de alta capacidad de los nodos terminales que o bien tienen limitaciones físicas debido a la capacidad de su enlace o bien no quieren destinar toda su capacidad a la retransmisión del flujo de información. De hecho, los nodos de alta capacidad pueden considerarse fuentes o bien porque generan físicamente el flujo o bien porque, recibiéndolo a través de otra red de distribución, lo retransmiten como fuente a los nodos de baja capacidad que conforman la red P2P. Una vez descrita la topología de distribución, se define el modelo matemático para su análisis. Para ello se normaliza el ancho de banda del flujo y se propone un algoritmo de ingreso de nodos en la red con el objeto de optimizar el retardo de distribución. A continuación, se caracteriza la topología de la red mediante tres parámetros: el número de nodos a los que puede servir el nodo fuente, el número de conexiones de descarga que deben llegar a un nodo para recibir el flujo a tasa unitaria y el número máximo de conexiones de subida que puede establecer un nodo. Asimismo, se segmenta el flujo de información en unidades genéricas, denominadas objetos, que se diseminan en la red a través de un determinado conjunto de árboles de difusión. El número de árboles de difusión se corresponde con el número de conexiones de descarga de los nodos. Todo esto permite obtener una expresión del número de nodos que, en condiciones de estabilidad, pueden conectarse a la red, así como una cota muy ajustada del retardo total de transmisión. Presentamos además una simulación que permite evaluar el rendimiento de la topología descrita en el entorno de redes VANET. De forma complementaria, en el último capítulo se presenta una propuesta de distribución multicast en la capa de aplicación que puede emplearse para transmitir el flujo de información desde el nodo que lo produce inicialmente hasta los nodos fuentes de las redes P2P de distribución.Postprint (published version