Towards a new generation of transport services adapted to multimedia application

Une connexion d'ordre et de fiabilité partiels (POC, partial order connection) est une connexion de transport autorisée à perdre certains objets mais également à les délivrer dans un ordre éventuellement différent de celui d'émission. L'approche POC établit un lien conceptuel entre les protocoles sans connexion au mieux et les protocoles fiables avec connexion. Le concept de POC est motivé par le fait que dans les réseaux hétérogènes sans connexion tels qu'Internet, les paquets transmis sont susceptibles de se perdre et d'arriver en désordre, entraînant alors une réduction des performances des protocoles usuels. De plus, on montre qu'un protocole associé au transport d'un flux multimédia permet une réduction très sensible de l'utilisation des ressources de communication et de mémorisation ainsi qu'une diminution du temps de transit moyen. Dans cet article, une extension temporelle de POC, nommée TPOC (POC temporisé), est introduite. Elle constitue un cadre conceptuel permettant la prise en compte des exigences de qualité de service des applications multimédias réparties. Une architecture offrant un service TPOC est également introduite et évaluée dans le cadre du transport de vidéo MPEG. Il est ainsi démontré que les connexions POC comblent, non seulement le fossé conceptuel entre les protocoles sans connexion et avec connexion, mais aussi qu'ils surpassent les performances des ces derniers lorsque des données multimédias (telles que la vidéo MPEG) sont transportées

Transport of video over partial order connections

A Partial Order and partial reliable Connection (POC) is an end-to-end transport connection authorized to deliver objects in an order that can differ from the transmitted one. Such a connection is also authorized to lose some objects. The POC concept is motivated by the fact that heterogeneous best-effort networks such as Internet are plagued by unordered delivery of packets and losses, which tax the performances of current applications and protocols. It has been shown, in several research works, that out of order delivery is able to alleviate (with respect to CO service) the use of end systems’ communication resources. In this paper, the efficiency of out-of-sequence delivery on MPEG video streams processing is studied. Firstly, the transport constraints (in terms of order and reliability) that can be relaxed by MPEG video decoders, for improving video transport, are detailed. Then, we analyze the performance gain induced by this approach in terms of blocking times and recovered errors. We demonstrate that POC connections fill not only the conceptual gap between TCP and UDP but also provide real performance improvements for the transport of multimedia streams such MPEG video

Service Oriented Architecture for VoIP Conferencing

Voice/Video over IP (VoIP) systems to date have been either highly centralized or dependent on the IP multicast in nature. Global Multimedia Collaboration System is a scalable, integrated and service-oriented VoIP conferencing system, based on the XGSP collaboration framework and NaradaBrokering messaging middleware. This system can provide media and session services to heterogeneous endpoints such as H.323, SIP, Access Grid, RealPlayer as well as cellular phone. In this paper, we address the challenges of scalability, interoperablity and heterogeneity in massive VoIP conferencing system. We believe that our approach opens up new opportunities for leveraging classic VoIP systems by using new technologies in service-oriented computing

Distributed Rate Allocation in Switch-Based Multiparty Videoconferencing System

Multiparty videoconferences, or more generally multiparty video calls, are gaining a lot of popularity as they offer a rich communication experience. These applications have, however, large requirements in terms of both network and computational resources and have to deal with sets of heterogenous clients. The multiparty videoconferencing systems are usually either based on expensive central nodes, called Multipoint Control Units (MCU), with transcoding capabilities, or on a peer-to-peer architecture where users cooperate to distribute more efficiently the different video streams. Whereas the first class of systems requires an expensive central hardware, the second one depends completely on the redistribution capacity of the users, which sometimes might neither provide sufficient bandwidth nor be reliable enough. In this work we propose an alternative solution where we use a central node to distribute the video streams, but at the same time we maintain the hardware complexity and the computational requirements of this node as low as possible, e.g. it has no video decoding capabilities. We formulate the rate allocation problem as an optimization problem that aims at maximizing the Quality of Service (QoS) of the videoconference. We propose two different distributed algorithms for solving the optimization problem: the first algorithm is able to find an approximate solution of the problem in a one-shot execution, whereas the second algorithm, based on Lagrangian relaxation, performs iterative updates of the optimization variables in order to gradually increase the value of the objective function. The two algorithms, though being disjointed, nicely complement each other. If executed in sequence, they allow to achieve both, a quick approximate rate reallocation in case of a sudden change of the system conditions, and a precise refinement of the variables which avoids problems caused by possible faulty approximate solutions. We have further implemented our solution in a network simulator where we show that our rate allocation algorithm is able to properly optimize users' QoS. We also illustrate the benefits of our solution in terms of network usage and overall utility when compared to a baseline heuristic method operating on the same system architecture

Quality of Service improvements for real time multimedia applications using next generation network architectures and blockchain in Internet Service Provider cooperative scenario

Real time communications are becoming part of our daily life, requiring constrained requisites with the purpose of being enjoyed in harmony by end users. The factors ruling these requisites are Quality of Service parameters of the users' Internet connections. Achieving a satisfactory QoS level for real time communications depends on parameters that are strongly influenced by the quality of the network connections among the Internet Service Providers, which are located in the path between final users and Over The Top service providers that are supplying them with real time services. Final users can be: business people having real time videoconferences, or adopting crytpocurrencies in their exchanges, videogamers playing online games together with others residing in other countries, migrants talking with their relatives or watching their children growing up in their home countries, people with disabilities adopting tecnologies to help them, doctors performing remote surgeries, manufacturers adopting augmented reality devices to perform dangerous tasks. Each of them performing their daily activities are requiring specific QoS parameters to their ISPs, that nowadays seem to be unable to provide them with a satisfactory QoS level for these kinds of real time services. Through the adoption of next generation networks, such as the Information Centric Networking, it would be possible to overcome the QoS problems that nowadays are experienced. By adopting Blockchain technologies, in several use cases, it would be possible to improve those security aspects related to the non-temperability of information and privacy. I started this thesis analyzing next generation architectures enabling real time multimedia communications. In Software Defined Networking, Named Data Networking and Community Information Centric Networking, I highlighted potential approaches to solve QoS problems that are affecting real time multimedia applications. During my experiments I found that applications able to transmit high quality videos, such as 4k or 8k videos, or to directly interact with devices AR/VR enabled are missing for both ICN approaches. Then I proposed a REST interface for the enforcing of a specific QoS parameter, the round trip time (RTT) taking into consideration the specific use case of a game company that connects with the same telecommunication company of the final user. Supposing that the proposed REST APIs have been deployed in the game company and in the ISP, when one or more users are experiencing lag, the game company will try to ask the ISP to reduce the RTT for that specific user or that group of users. This request can be done by performing a call to a method where IP address(es) and the maximum RTT desired are passed. I also proposed other methods, through which it would be possible to retrieve information about the QoS parameters, and exchange, if necessary, an exceeding parameter in change of another one. The proposed REST APIs can also be used in more complex scenarios, where ISPs along the path are chained together, in order to improve the end to end QoS among Over The Top service provider and final users. To store the information exchanged by using the proposed REST APIs, I proposed to adopt a permissioned blockchain, analizying the ISPs cooperative use case with Hyperledger Fabric, where I proposed the adoption of the Proof of Authority consensus algorithm, to increase the throughput in terms of transactions per second. In a specific case that I examined, I am proposing a combination of Information Centric Networking and Blockchain, in an architecture where ISPs are exchanging valuable information regarding final Users, to improve their QoS parameters. I also proposed my smart contract for the gaming delay use case, that can be used to rule the communication among those ISPs that are along the path among OTT and final users. An extension of this work can be done, by defining billing costs for the QoS improvements

Traffic behavior and performance in VOIP

This thesis report is submitted in partial fulfillment of the requirements for the degree of Bachelor of Science in Computer Science and Engineering, 2008.Cataloged from PDF version of thesis report.Includes bibliographical references (page 48-49).Voice over Internet protocol - VoIP, or IP telephony is a technology by which the routing of voice communications are done through Internet or any other Internet Protocol (IP) based networks. Here the voice data is transmitted over a general purpose packet-switched network instead of dedicated traditional circuit-switched voice transmission lines. Voice Over Internet Protocol (VoIP) is a telephony technology used to transmit ordinary telephone calls over the Internet. VoIP takes analogue audio signals and turns them into digital signals (packets) that are transmitted using Internet Protocol (IP) networks. VoIP’s advantages include low cost, flexibility, and mobility. Conversely, VoIP’s disadvantages include sound quality such as latency (delay), jitter, and packet loss. To be more precise the main goal of my thesis was to study the traffic behavior of VoIP. To find out the factors that effect on the performance of VoIP and to mitigate that problems in the network was the main goal hereAshis Kumar SahaB. Computer Science and Engineerin

MediaSync: Handbook on Multimedia Synchronization

This book provides an approachable overview of the most recent advances in the fascinating field of media synchronization (mediasync), gathering contributions from the most representative and influential experts. Understanding the challenges of this field in the current multi-sensory, multi-device, and multi-protocol world is not an easy task. The book revisits the foundations of mediasync, including theoretical frameworks and models, highlights ongoing research efforts, like hybrid broadband broadcast (HBB) delivery and users' perception modeling (i.e., Quality of Experience or QoE), and paves the way for the future (e.g., towards the deployment of multi-sensory and ultra-realistic experiences). Although many advances around mediasync have been devised and deployed, this area of research is getting renewed attention to overcome remaining challenges in the next-generation (heterogeneous and ubiquitous) media ecosystem. Given the significant advances in this research area, its current relevance and the multiple disciplines it involves, the availability of a reference book on mediasync becomes necessary. This book fills the gap in this context. In particular, it addresses key aspects and reviews the most relevant contributions within the mediasync research space, from different perspectives. Mediasync: Handbook on Multimedia Synchronization is the perfect companion for scholars and practitioners that want to acquire strong knowledge about this research area, and also approach the challenges behind ensuring the best mediated experiences, by providing the adequate synchronization between the media elements that constitute these experiences

A Semantic-Based Middleware for Multimedia Collaborative Applications

The Internet growth and the performance increase of desktop computers have enabled large-scale distributed multimedia applications. They are expected to grow in demand and services and their traffic volume will dominate. Real-time delivery, scalability, heterogeneity are some requirements of these applications that have motivated a revision of the traditional Internet services, the operating systems structures, and the software systems for supporting application development. This work proposes a Java-based lightweight middleware for the development of large-scale multimedia applications. The middleware offers four services for multimedia applications. First, it provides two scalable lightweight protocols for floor control. One follows a centralized model that easily integrates with centralized resources such as a shared too], and the other is a distributed protocol targeted to distributed resources such as audio. Scalability is achieved by periodically multicasting a heartbeat that conveys state information used by clients to request the resource via temporary TCP connections. Second, it supports intra- and inter-stream synchronization algorithms and policies. We introduce the concept of virtual observer, which perceives the session as being in the same room with a sender. We avoid the need for globally synchronized clocks by introducing the concept of user\u27s multimedia presence, which defines a new manner for combining streams coming from multiple sites. It includes a novel algorithm for estimation and removal of clock skew. In addition, it supports event-driven asynchronous message reception, quality of service measures, and traffic rate control. Finally, the middleware provides support for data sharing via a resilient and scalable protocol for transmission of images that can dynamically change in content and size. The effectiveness of the middleware components is shown with the implementation of Odust, a prototypical sharing tool application built on top of the middleware

Predictable multi-processor system on chip design for multimedia applications

The design of multimedia systems has become increasingly complex due to consumer requirements. Consumers demand the functionalities offered by a huge desktop from these systems. Many of these systems are mobile. Therefore, power consumption and size of these devices should be small. These systems are increasingly becoming multi-processor based (MPSoCs) for the reasons of power and performance. Applications execute on these systems in different combinations also known as use-cases. Applications may have different performance requirements in each use-case. Currently, verification of all these use-cases takes bulk of the design effort. There is a need for analysis based techniques so that the platforms have a predictable behaviour and in turn provide guarantees on performance without expending precious man hours on verification. In this dissertation, techniques and architectures have been developed to design and manage these multi-processor based systems efficiently. The dissertation presents predictable architectural components for MPSoCs, a Predictable MPSoC design strategy, automatic platform synthesis tool, a run-time system and an MPSoC simulation technique. The introduction of predictability helps in rapid design of MPSoC platforms. Chapter 1 of the thesis studies the trends in modern multimedia applications and processor architectures. The chapter further highlights the problems in the design of MPSoC platforms and emphasizes the need of predictable design techniques. Predictable design techniques require predictable application and architectural components. The chapter further elaborates on Synchronous Data Flow Graphs which are used to model the applications throughout this thesis. The chapter presents the architecture template used in this thesis and enlists the contributions of the thesis. One of the contributions of this thesis is the design of a predictable component called communication assist. Chapter 2 of the thesis describes the architecture of this communication assist. The communication assist presented in this thesis not only decouples the communication from computation but also provides timing guarantees. Based on this communication assist, an MPSoC platform generation technique has been presented that can design MPSoC platforms capable of satisfying the throughput constraints of multiple applications in all use-cases. The technique is presented in Chapter 3. The design strategy uses three simple steps for platform design. In the first step it finds the required number of processors. The second step minimizes the communication interconnect between the processors and the third step minimizes the communication memory requirement of the platform. Further in Chapter 4, a tool has been developed to generate CA-based platforms for FPGAs. The output of this tool can be used to synthesize platforms on real hardware with the help of FPGA synthesis tools. The applications executing on these platforms often exhibit dynamism e.g. variation in task execution times and change in application throughput requirements. Further, new applications may often be added by consumers at run-time. Resource managers have been presented in literature to handle such dynamic situations. However, the scalability of these resource managers becomes an issue with the increase in number of processors and applications. Chapter 5 presents distributed run-time resource management techniques. Two versions of distributed resource managers have been presented which are scalable with the number of applications and processors. MPSoC platforms for real-time applications are designed assuming worst-case task execution times. It is known that the difference between average-case and worst-case behaviour can be quite large. Therefore, knowing the average case performance is also important for the system designer, and software simulation is often employed to estimate this. However, simulation in software is slow and does not scale with the number of applications and processing elements. In Chapter 6, a fast and scalable simulation methodology is introduced that can simulate the execution of multiple applications on an MPSoC platform. It is based on parallel execution of SDF (Synchronous Data Flow) models of applications. The simulation methodology uses Parallel Discrete Event Simulation (PDES) primitives and it is termed as "Smart Conservative PDES". The methodology generates a parallel simulator which is synthesizable on FPGAs. The framework can also be used to model dynamic arbitration policies which are difficult to analyse using models. The generated platform is also useful in carrying out Design Space Exploration as shown in the thesis. Finally, Chapter 7 summarizes the main findings and (practical) implications of the studies described in previous chapters of this dissertation. Using the contributions mentioned in the thesis, a designer can design and implement predictable multiprocessor based systems capable of satisfying throughput constraints of multiple applications in given set of use-cases, and employ resource management strategies to deal with dynamism in the applications. The chapter also describes the main limitations of this dissertation and makes suggestions for future research