165 research outputs found
Peer-to-peer live video streaming with rateless codes for massively multiplayer online games
International audienc
Ad-hoc Stream Adaptive Protocol
With the growing market of smart-phones, sophisticated applications that do extensive computation are common on mobile platform; and with consumers’ high expectation of technologies to stay connected on the go, academic researchers and industries have been making efforts to find ways to stream multimedia contents to mobile devices. However, the restricted wireless channel bandwidth, unstable nature of wireless channels, and unpredictable nature of mobility, has been the major road block for wireless streaming advance forward. In this paper, various recent studies on mobility and P2P system proposal are explained and analyzed, and propose a new design based on existing P2P systems, aimed to solve the wireless and mobility issues
Optimizing on-demand resource deployment for peer-assisted content delivery (PhD thesis)
Increasingly, content delivery solutions leverage client resources in exchange for service in a peer-to-peer (P2P) fashion. Such peer-assisted service paradigms promise significant infrastructure cost reduction, but suffer from the unpredictability associated with client resources, which is often exhibited as an imbalance between the contribution and consumption of resources by clients. This imbalance hinders the ability to guarantee a minimum service fidelity of these services to the clients. In this thesis, we propose a novel architectural service model that enables the establishment of higher fidelity services through (1) coordinating the content delivery to optimally utilize the available resources, and (2) leasing the least additional cloud resources, available through special nodes (angels) that join the service on-demand, and only if needed, to complement the scarce resources available through clients. While the proposed service model can be deployed in many settings, this thesis focuses on peer-assisted content delivery applications, in which the scarce resource is typically the uplink capacity of clients. We target three applications that require the delivery of fresh as opposed to stale content. The first application is bulk-synchronous transfer, in which the goal of the system is to minimize the maximum distribution time -- the time it takes to deliver the content to all clients in a group. The second application is live streaming, in which the goal of the system is to maintain a given streaming quality. The third application is Tor, the anonymous onion routing network, in which the goal of the system is to boost performance (increase throughput and reduce latency) throughout the network, and especially for bandwidth-intensive applications. For each of the above applications, we develop mathematical models that optimally allocate the already available resources. They also optimally allocate additional on-demand resource to achieve a certain level of service. Our analytical models and efficient constructions depend on some simplifying, yet impractical, assumptions. Thus, inspired by our models and constructions, we develop practical techniques that we incorporate into prototypical peer-assisted angel-enabled cloud services. We evaluate those techniques through simulation and/or implementation.
(Major Advisor: Azer Bestavros
Optimizing on-demand resource deployment for peer-assisted content delivery
Increasingly, content delivery solutions leverage client resources in exchange for services in a pee-to-peer (P2P) fashion. Such peer-assisted service paradigm promises significant infrastructure cost
reduction, but suffers from the unpredictability associated with client resources, which is often exhibited as an imbalance between the contribution and consumption of resources by clients. This imbalance hinders the ability to guarantee a minimum service fidelity of these services to clients especially for real-time applications where content can not be cached. In this thesis, we propose a
novel architectural service model that enables the establishment of higher fidelity services through (1) coordinating the content delivery to efficiently utilize the available resources, and (2) leasing the least additional cloud resources, available through special nodes (angels) that join the service on-demand, and only if needed, to complement the scarce resources available through clients.
While the proposed service model can be deployed in many settings, this thesis focuses on peer-assisted content delivery applications, in which the scarce resource is typically the upstream
capacity of clients. We target three applications that require the delivery of real-time as opposed to stale content. The first application is bulk-synchronous transfer, in which the goal of the system is
to minimize the maximum distribution time - the time it takes to deliver the content to all clients in a group. The second application is live video streaming, in which the goal of the system is to maintain
a given streaming quality. The third application is Tor, the anonymous onion routing network, in which the goal of the system is to boost performance (increase throughput and reduce latency)
throughout the network, and especially for clients running bandwidth-intensive applications.
For each of the above applications, we develop analytical models that efficiently allocate the already available resources. They also efficiently allocate additional on-demand resource to achieve
a certain level of service. Our analytical models and efficient constructions depend on some simplifying, yet impractical, assumptions. Thus, inspired by our models and constructions, we develop practical techniques that we incorporate into prototypical peer-assisted angel-enabled cloud services.
We evaluate these techniques through simulation and/or implementation
Video-on-Demand over Internet: a survey of existing systems and solutions
Video-on-Demand is a service where movies are delivered to distributed users with low delay and free interactivity. The traditional client/server architecture experiences scalability issues to provide video streaming services, so there have been many proposals of systems, mostly based on a peer-to-peer or on a hybrid server/peer-to-peer solution, to solve this issue. This work presents a survey of the currently existing or proposed systems and solutions, based upon a subset of representative systems, and defines selection criteria allowing to classify these systems. These criteria are based on common questions such as, for example, is it video-on-demand or live streaming, is the architecture based on content delivery network, peer-to-peer or both, is the delivery overlay tree-based or mesh-based, is the system push-based or pull-based, single-stream or multi-streams, does it use data coding, and how do the clients choose their peers. Representative systems are briefly described to give a summarized overview of the proposed solutions, and four ones are analyzed in details. Finally, it is attempted to evaluate the most promising solutions for future experiments. Résumé La vidéo à la demande est un service où des films sont fournis à distance aux utilisateurs avec u
Flexible Application-Layer Multicast in Heterogeneous Networks
This work develops a set of peer-to-peer-based protocols and extensions in order to provide Internet-wide group communication. The focus is put to the question how different access technologies can be integrated in order to face the growing traffic load problem. Thereby, protocols are developed that allow autonomous adaptation to the current network situation on the one hand and the integration of WiFi domains where applicable on the other hand
Observing and Improving the Reliability of Internet Last-mile Links
People rely on having persistent Internet connectivity from their homes and
mobile devices. However, unlike links in the core of the Internet, the links
that connect people's homes and mobile devices, known as "last-mile" links, are
not redundant. As a result, the reliability of any given link is of paramount
concern: when last-mile links fail, people can be completely disconnected from
the Internet.
In addition to lacking redundancy, Internet last-mile links are vulnerable to
failure. Such links can fail because the cables and equipment that make up
last-mile links are exposed to the elements; for example, weather can cause
tree limbs to fall on overhead cables, and flooding can destroy underground
equipment. They can also fail, eventually, because cellular last-mile links can
drain a smartphone's battery if an application tries to communicate when signal
strength is weak.
In this dissertation, I defend the following thesis: By building on existing
infrastructure, it is possible to (1) observe the reliability of Internet
last-mile links across different weather conditions and link types; (2) improve
the energy efficiency of cellular Internet last-mile links; and (3) provide an
incrementally deployable, energy-efficient Internet last-mile downlink that is
highly resilient to weather-related failures. I defend this thesis by
designing, implementing, and evaluating systems
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
Efficient Passive Clustering and Gateways selection MANETs
Passive clustering does not employ control packets to collect topological information in ad hoc networks. In our proposal, we avoid making frequent changes in cluster architecture due to repeated election and re-election of cluster heads and gateways. Our primary objective has been to make Passive Clustering more practical by employing optimal number of gateways and reduce the number of rebroadcast packets
Realtime Streaming with Guaranteed QOS over Wireless D2D Networks
The increase in the processing power of mobile devices has led to an explosion of available services and applications. However, the cost of mobile data is a hindrance to the adoption of data intensive applications. We consider a group of co-located wireless peer devices that desire to synchronously receive a live content stream. Devices desire to minimize the usage of their B2D interfaces (3G/4G) to reduce cost, while maintaining synchronous reception and playout of content. While it might be
possible for a cellular base station to broadcast or multicast live events to multiple handsets, such content would be restricted to a few selected channels, and only available to subscribers of a single provider. Utilizing both B2D and D2D (WiFi) interfaces enables users to pick any event of interest, and "stitch together" their B2D capacities regardless of provider support. Our objective is to enable users to listen or watch real time streams while incurring only a fraction of the original costs.
Our system setup is as follows. The real-time stream is divided into blocks, which must be played out soon after their initial creation. If a block is not received within a specific time after its creation, it is rendered useless and dropped. The blocks in turn are divided into random linear coded chunks to facilitate sharing across the devices. We transform the problem into the two questions of (i) deciding which peer should broadcast a chunk on the D2D channel at each time, and (ii) how long B2D
transmissions should take place for each block.
The thesis studies the performance of a provably-minimum-cost algorithm that can ensure that QoS targets can be met for each device. We use a Lyapunov stability argument to show that a stable delivery ratio can be achieved using our mechanism. We show that the optimal D2D scheduling algorithm has a simple and intuitive form under reliable broadcast, which allows for easy implementation and development of good heuristics. We study this via simulations, and present an overview of the implementation on Android phones using the algorithm as a basis. Additionally, we
design an incentive framework that promotes cooperation among devices. We show that under this incentive framework, each device benefits by truthfully reporting the number of chunks that it received via B2D and its deficit in each frame, so that a system-wide optimal allocation policy can be employed. The incentive framework developed is lightweight and compatible with minimal amounts of history retention.
The Android testbed used in the experiments consisted of multiple Google Nexus 4 phones. A modified version of Android Jelly Bean (v 4.3) was built in order to conduct the experiments which removes the limitation wherein the phone switches off its 3G data connection (B2D) whenever a known WiFi network (D2D) becomes available. Since the Nexus 4 devices are incapable of operating in ad-hoc mode, we used a WiFi network (without Internet connectivity) to emulate the D2D part.
Hence, devices must use their 3G interfaces to receive chunks for the server (via the Internet). We present experimental results, and show that it would be possible to follow popular streams on hand held devices incurring only a fraction of the costs while achieving a high QoS
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