1. Efficient Streaming for Delay-tolerant Multimedia Applications Saraswathi Krithivasan Advisor: Prof. Sridhar Iyer

2. Problem Definition Given: A multicast tree with source S serving clients C i s Resources such as transcoders, layer encoders, and streaming servers; Each C i specifies two requirements: a minimum acceptable rate α min and δi, the time it is willing to wait, once connection is established, for start of playout of content; Content has playout duration T and base encoding rate α Assumptions: The topology is known with link bandwidths remaining constant over a given prediction interval P.

3. Problem Definition Leverage delay tolerance δ i, specified by each C i to provide (for each C i ): continuous playout at r i such that r i s across all C i s are maximized and each r i is greater than or equal to α min.

4. Problem space

5. Our context

6. Key assumptions The network topology is known and static a subscription based network different streaming sessions may have different clients participating Buffers are available at all network nodes unlimited buffers for the analysis of the cases considered Buffer management issues including the case of memory constrained client devices are addressed Client requirements are known. The minimum rate requirement α i of C i, is used mainly as an admission control parameter When α min is not defined by the client, a minimum rate (say 128 kbps) is assumed to be required. End-to-end delays are negligible.

7. Service types Bandwidth Resource used ScheduledOn-demand Varying Layered encoder /streamer Static Transcoder/streamer Parameters defining dimensions of the problem

8. Contributions: Scheduled streaming, Static bandwidth case Details Example

9. Contributions: Scheduled streaming, Varying bandwidth case Example Details

10. Contributions: On-demand streaming, Static bandwidth case Details Overview

11. Node architectures Scheduled streaming Source Node architecturearchitecture Relay Node architecturearchitecture Client Node architecture architecture On-demand streaming Source Node – with data transfer capabilities architecture architecture Streaming Relay Node – with streaming capabilities architecturearchitecture

12. Buffer: Resource management issues Buffer requirements At Source/ relay node B ni max = Σ P (b i p − b j p ) × P, where P is the prediction interval duration At a client node When the last link to the client supports the optimal delivered rate at a client, buffers can be moved up to the upstream relay node. When the last link is the weakest link in the client’s path, it is necessary that adequate buffers are available at the client to support play out at the optimal rate. Size and duration over which buffer is maintained depends on δ value of client

13. Effect of δ on buffer requirement When there is no sharing link constraint, increasing δ j value of a client C j, improves delivered rate δ j value for which client receives stream at Γ is denoted by đ j Beyond đ j no improvement in delivered rate; stream is buffered at client till playout When δ j takes values between đ j and (đ j +T ), mechanism moves from streaming to partial downloading to complete downloading at (đ j + T). When δ j takes values greater than (đ j + T), it is equivalent to complete download and play back at a convenient time. entire content is stored at the client for a time (δ j − (đ j +T)). Leads to the interesting notion of “residual delay tolerance” đ R = (δ j − đ j ).

14. Service types Bandwidth Resource used ScheduledOn-demand Varying Layered encoder /streamer Static Transcoder/streamer To summarize ……..

15. Other interesting research problems… In VoD scenario, the following problems pose interesting challenges: handling new requests during a scheduled streaming session handling multiple servers with independent or partially overlapping contents. On-demand streaming, varying bandwidths case needs to be studied in depth. In-depth analysis of running delay-tolerant applications on wireless devices Exploring possibilities of extending declarative networking frameworks to facilitate the implementation of our proposed algorithms Analyzing the problem in a business perspective

16. Future work: A planning tool for CSPs

17. Selected publications S. Krithivasan, S. Iyer, Strategies for Efficient Streaming in Delay-tolerant Multimedia Applications, IEEE-ISM 2006, Sandiego, USA, December 2006.Strategies for Efficient Streaming in Delay-tolerant Multimedia Applications A. Th. Rath, S. Krithivasan, S. Iyer, HSM: A Hybrid Streaming Mechanism for Delay- tolerant Multimedia Applications, MoMM 2006, Yogyakarta, Indonesia, December 2006.HSM: A Hybrid Streaming Mechanism for Delay- tolerant Multimedia Applications S. Krithivasan, S. Iyer, Enhancing QoS for Delay-tolerant Multimedia Applications: Resource Utilization and Scheduling from a Service Provider's Perspective, Infocom 2006, Barcelona, Spain, April 2006.Enhancing QoS for Delay-tolerant Multimedia Applications: Resource Utilization and Scheduling from a Service Provider's Perspective S. Krithivasan, S. Iyer, Maximizing Revenue through Resource Provisioning and Scheduling in Delay-tolerant Multimedia Applications: A Service Provider's Prespective, Infocom 2006, Barcelona, Spain, April 2006.Maximizing Revenue through Resource Provisioning and Scheduling in Delay-tolerant Multimedia Applications: A Service Provider's Prespective S. Krithivasan, S. Iyer, Enhancing Quality of Service by Exploiting Delay Tolerance in Multimedia Applications, ACM Multimedia 2005, Singapore, November 2005.Enhancing Quality of Service by Exploiting Delay Tolerance in Multimedia Applications S. Krithivasan, S. Iyer, To Beam or to Stream: Satellite-based vs. Streaming-based Infrastructure for Distance Education, Edmedia, World Conference on Educational Multimedia, Hypermedia & Telecommunications 2004, Lugano, Switzerland, June 2004.To Beam or to Stream: Satellite-based vs. Streaming-based Infrastructure for Distance Education S. Krithivasan, S. Iyer, Mechanisms for Effective and Efficient Dissemination of Multimedia, Technical Report, Kanwal Rekhi School of Information Technology (KReSIT), IIT Bombay, September 2004.Mechanisms for Effective and Efficient Dissemination of Multimedia

18. Thank you