A Comprehensive Analysis of Swarming-based Live Streaming to Leverage Client Heterogeneity

Due to missing IP multicast support on an Internet scale, over-the-top media streams are delivered with the help of overlays as used by content delivery networks and their peer-to-peer (P2P) extensions. In this context, mesh/pull-based swarming plays an important role either as pure streaming approach or in combination with tree/push mechanisms. However, the impact of realistic client populations with heterogeneous resources is not yet fully understood. In this technical report, we contribute to closing this gap by mathematically analysing the most basic scheduling mechanisms latest deadline first (LDF) and earliest deadline first (EDF) in a continuous time Markov chain framework and combining them into a simple, yet powerful, mixed strategy to leverage inherent differences in client resources. The main contributions are twofold: (1) a mathematical framework for swarming on random graphs is proposed with a focus on LDF and EDF strategies in heterogeneous scenarios; (2) a mixed strategy, named SchedMix, is proposed that leverages peer heterogeneity. The proposed strategy, SchedMix is shown to outperform the other two strategies using different abstractions: a mean-field theoretic analysis of buffer probabilities, simulations of a stochastic model on random graphs, and a full-stack implementation of a P2P streaming system.Comment: Technical report and supplementary material to http://ieeexplore.ieee.org/document/7497234

Wooster Magazine: Winter 2012

This edition of the Wooster Magazine was published in the Winter of 2012. Students in Professor Mangubi\u27s printmaking class last semester created very large prints with the help of a 12 ton steamroller. The college has a new core message to deliver, America\u27s premier college for mentored undergraduate research. Recent books published by alumni are on page six. The Communication Sciences and Disorders major is featured from page eight to nineteen. The next section highlights alumni and current students/faculty working with sculpture as their art medium of choice. Annie B Irish was Wooster\u27s first female faculty member and PhD recipient, her legacy is recalled from page 29 to 35.https://openworks.wooster.edu/wooalumnimag_2011-present/1023/thumbnail.jp

Flexible Traffic Management in Broadband Access Networks using Software Defined Networking

Abstract-Over the years, the demand for high bandwidth services, such as live and on-demand video streaming, steadily increased. The adequate provisioning of such services is challenging and requires complex network management mechanisms to be implemented by Internet service providers (ISPs). In current broadband network architectures, the traffic of subscribers is tunneled through a single aggregation point, independent of the different service types it belongs to. While having a single aggregation point eases the management of subscribers for the ISP, it implies huge bandwidth requirements for the aggregation point and potentially high end-to-end latency for subscribers. An alternative would be a distributed subscriber management, adding more complexity to the management itself. In this paper, a new traffic management architecture is proposed that uses the concept of Software Defined Networking (SDN) to extend the existing Ethernet-based broadband network architecture, enabling a more efficient traffic management for an ISP. By using SDN-enabled home gateways, the ISP can configure traffic flows more dynamically, optimizing throughput in the network, especially for bandwidth-intensive services. Furthermore, a proofof-concept implementation of the approach is presented to show the general feasibility and study configuration tradeoffs. Analytic considerations and testbed measurements show that the approach scales well with an increasing number of subscriber sessions

Video-Streaming Overlays

This Chapter goes into the details of benchmarking peer-to-peer video streaming systems. We present aspects and techniques that help comparing and analyzing such systems. Video streaming systems have the main task of delivering video content to users. The video content can be presented on various types of devices, such as TV sets, computer systems, and smart phones. The availability of many types of architectures for streaming makes it of essence to define benchmarks and tools to evaluate them. This Chapter addresses these issues along with definitions of metrics and requirements that help in better comparing peer-to-peer streaming systems. The Chapter is organized as follows. First, we present the non-functional requirements peer-to-peer video streaming systems have to consider. Then we present the workload used to benchmark our video streaming system. This is followed by definition of most important metrics for such systems. Then we present an example implementation that ha..

Bridging the Gap: Towards an Adaptive Video Streaming Approach Supporting Transitions

Part 3: PhD Workshop—High-Speed Networks and Network ManagementInternational audienceVideo streaming over the Internet is becoming increasingly popular. Existing streaming systems range from traditional client/server to peer-to-peer-based approaches. However, no single streaming mechanism fits all possible video streaming scenarios. Therefore, this paper proposes a novel adaptive video streaming approach supporting transitions between different mechanisms in order to provide a stable Quality of Service to streaming clients. Two stages of adaptation are identified and challenges of different transitions are discussed

Software-Defined Multicast for Over-the-Top and Overlay-based Live Streaming in ISP Networks

The increasing amount of over-the-top (OTT) live streams and the lack of global network layer multicast support poses challenges for a scalable and efficient streaming over the Internet. Content Delivery Networks (CDNs) help by delivering the streams to the edge of almost every Internet Service Provider (ISP) network of the world but usually also end there. From there on, the streams are to be delivered to the clients using IP unicast, although an IP multicast functionality would be desirable to reduce the load on CDN nodes, transit links, and the ISP infrastructure. IP multicast is usually not available due to missing control and management features of the protocol. Alternatively, Peer-to-Peer (P2P) mechanisms can be applied to extend the overlay multicast functionality of the CDN towards the clients. Unfortunately, P2P only improves the situation for the CDN but makes it more challenging for the ISP as even more unicast flows are generated between clients inside and outside the ISP network. To tackle this problem, a Software-Defined Networking-based cross-layer approach, called Software-Defined Multicast (SDM), is proposed in this paper, enabling ISPs to offer network layer multicast support for OTT and overlay-based live streaming as a service. SDM is specifically tailored towards the needs of P2P-based video stream delivery originating from outside the ISP network and can easily be integrated with existing streaming systems. Prototypical evaluations show significantly improved network layer transmission efficiencies when compared to other overlay streaming mechanisms, down to a level as low as for IP multicast, at linearly bounded costs

Clubbing with the Peers: A Measurement Study of BitTorrent Live

The peer-to-peer approach can greatly help to cope with highly dynamic live streaming workload by using idle client resources. Yet, P2P streaming typically comes at the cost of increased streaming delays caused by the inevitable multi-hop forwarding of content by peers within the overlay. Various P2P streaming approaches have been proposed aiming at a good tradeoff between flexibility, streaming delay, and costs in terms of traffic overhead for both content providers and clients. Recently, BitTorrent Inc. released a new P2P live streaming system termed BTLive, specifically targeted at low delay and low overhead. For content providers investigating the applicability of BTLive's approach, it is essential to understand its properties as well as its limitations. So far, no publicly available study exists that quantitatively analyzes BTLive's performance. To this end, this paper presents a measurement study of the official beta version of BTLive. The study aims to answer the following key questions: How peer-to-peer is BTLive? How delay optimized is BTLive? What is the overhead of BTLive? To answer these questions, traces of real BTLive traffic between a broadcast server and a number of peers deployed across Europe have been analyzed