Deployment of a large-scale multimedia streaming application requires an enormous amount of server and network resources. The simplest delivery technique allocates server resources for each specific request. This technique is very expensive and is not scalable to support a very large user community such as the Internet. Hence, the past decade has witnessed tremendous research efforts to facilitate cost-effective, large-scale deployment of multimedia streaming applications. In this paper, we describe three complementary research approaches: server transmission schemes using multicast, streaming strategies with application layer multicast, and proxy caching techniques. We discuss pros and cons of these technologies and provide our observations on current business solutions.

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Video delivery technologies for large-scale deployment of multimedia applications

The emergence of the Internet as a pervasive communication medium, and the widespread availability of digital video technology have led to the rise of several networked streaming media applications such as live video broadcasts, distance education and corporate telecasts. This paper studies the traffic associated with two major categories of streaming content on-demand streaming of pre-recorded content and live broadcasting. Using streaming logs from a commercial service, we analyze the traffic along a number of dimensions such as session characterization, object popularity, protocol choice and network load. Among our findings, (i) high bandwidth encodings account for about twice as many requests as low bandwidth ones, and make up about 94% of the traffic, (ii) Windows Media streams account for more than 75% of all requests, when the content is available in both Windows and Real formats, (iii) TCP based transport protocols dominate over UDP being used in about 70% of all bytes transfered (iv) Object popularities exhibit substantial skew with a few objects accounting for most of the load, (v) A small percentage of IP addresses (or routing prefixes or origin autonomous systems (ASes)) account for most of the traffic demand across a range of performance metrics. This last behavior suggests that substantial bandwidth efficiency can be realized with a distribution infrastructure comprised of a relatively small number of replicas, placed close to the heavy-hitter ASes. We also found very high variability in terms of the traffic volume with an order of magnitude or more increase in the offered load over tens of minutes, suggesting the potential benefit of a shared infrastructure that can exploit statistical multiplexing.

/pdf/streaming-video-traffic-characterization-and-network-impact-j1tm0ccli3.pdf

Streaming Video Traffic : Characterization and Network Impact

Multimedia streaming applications consume a significant amount of server and network resources due to the high bandwidth and long duration of audio and video clips. Patching and periodic broadcast schemes use multicast transmission and client buffering in innovative ways to reduce server and network resource use. Current research in this area has focussed on the theoretical aspects of these approaches, rather than on the challenges involved in implementing and deploying such scalable video transmission services. In this paper, we first describe the design and implementation of a flexible streaming video server and client testbed that can support emerging streaming services such as periodic broadcast and patching. We explore and present solutions to the system and network issues involved in actually implementing these services. Using this testbed, we conduct extensive experimental evaluations, measuring performance both at the server as well as end-end performance at the client, over the local network as well as over VBNS, and present key insights gained from our implementation and experimental evaluations.

https://www.eecs.wsu.edu/~holder/courses/cse6362/pubs/Bradshaw01.pdf

Periodic broadcast and patching services: implementation, measurement, and analysis in an Internet streaming video testbed

Recently, a number of scalable stream sharing protocols have been proposed with the promise of great reductions in the server and network bandwidth required for delivering popular media content. Although the scalability of these protocols has been evaluated mostly for sequential user accesses, a high degree of interactivity has been observed in the accesses to several real media servers. Moreover, some studies have indicated that user interactivity can severely penalize the scalability of stream sharing protocols.This paper investigates alternative mechanisms for scalable streaming to interactive users. We first identify a set of workload aspects that are determinant to the scalability of classes of streaming protocols. Using real workloads and a new interactive media workload generator, we build a rich set of realistic synthetic workloads. We evaluate Bandwidth Skimming and Patching, two state-of-the-art streaming protocols, covering, with our workloads, a larger region of the design space than previous work. Finally, we propose and evaluate five optimizations to Bandwidth Skimming, the most scalable of the two protocols. Our best optimization reduces the average server bandwidth required for interactive workloads in up to 54%, for unlimited client buffers, and 29%, if buffers are constrained to 25% of media size.

https://homepages.dcc.ufmg.br/~cunha/papers/rocha05mm-interactive.pdf

Scalable media streaming to interactive users

Multimedia streaming applications can consume a significant amount of server and network resources Periodic broadcast and patching are two approaches that use multicast transmission and client buffering in innovative ways to reduce server and network load, while at the same time allowing asynchronous access to multimedia streams by a large number of clients Current research in this area has focussed primarily on the algorithmic aspects of these approaches, with evaluation performed via analysis or simulation In this paper, we describe the design and implementation of a flexible streaming video server and client test bed that implements both periodic broadcast and patching, and explore the issues that arise when implementing these algorithms using laboratory and internet-based test beds We present measurements detailing the overheads associated with the various server components (signaling, transmission schedule computation, data retrieval and transmission), the interactions between the various components of the architecture, and the overall end-to-end performance We also discuss the importance of an appropriate server application-level caching policy for reducing the needed disk bandwidth at the server We conclude with a discussion of the insights gained from our implementation and experimental evaluation

Periodic broadcast and patching services - implementation, measurement and analysis in an internet streaming video testbed

Multimedia streaming applications can consume a significant amount of server and network resources. Periodic broadcast and patching are two approaches that use multicast transmission and client buffering in innovative ways to reduce server and network load, while at the same time allowing asynchronous access to multimedia steams by a large number of clients. Current research in this area has focussed primarily on the algorithmic aspects of these approaches, with evaluation performed via analysis or simulation. In this paper, we describe the design and implementation of a flexible streaming video server and client testbed that implements both periodic broadcast and patching, and explore the issues that arise when implementing these algorithms. We present measurements detailing the overheads associated with the various server components (signaling, transmission schedule computation, data retrieval and transmission), the interactions between the various components of the architecture, and the overall end-to-end performance. We also discuss the importance of an appropriate server video segment caching policy. We conclude with a discussion of the insights gained from our implementation and experimental evaluation.

Periodic broadcast and patching services: implementation, measurement, and analysis in an internet streaming video testbed

We present the design, implementation, and performance evaluation of AMPS --- a flexible, scalable proxy testbed that supports a wide and extensible set of next-generation proxy streaming services. AMPS employs a modular architecture and is built on top of a commodity Linux system. We study the performance of AMPS proxy using a server-proxy-client configuration in a switched-Gigabit LAN environment. We identify the CPU to be the system bottleneck. Through profiling study, we further identify the kernel network protocol processing and the Network Reception Module inside the proxy to be the most CPU-intensive components. We also quantify the maximum achievable throughput for two of the principal components of the proxy - the control plane and data plane, and characterize the end-to-end performance along the server-to-proxy-to-client path. We discuss lessons learned and the various optimizations made in the course of our study to improve system performance.

AMPS: a flexible, scalable proxy testbed for implementing streaming services

Multimedia systems use stream modules to perform operations on the streams that pass through them. To create services, programmers hand-code modules together to form a pipeline. While some advances have been made in automating this process, none yet exist that create pipelines that are fully aware of the system's resources. In this paper, we present the design and evaluation of the Graph Manager (GM), a pipeline scheduler that determines, on-the-fly, the best way to satisfy requests using stream modules and reusing existing streams in the system.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Michael K. Bradshaw

Papers

Periodic broadcast and patching services: implementation, measurement, and analysis in an Internet streaming video testbed

Periodic broadcast and patching services - implementation, measurement and analysis in an internet streaming video testbed

Periodic broadcast and patching services: implementation, measurement, and analysis in an internet streaming video testbed

AMPS: a flexible, scalable proxy testbed for implementing streaming services

A reconfigurable, on-the-fly, resource-aware, streaming pipeline scheduler