1. Efficient Transmission of Rendering-Related Data Using the NIProxy Maarten Wijnants Tom Jehaes Peter Quax Wim Lamotte Hasselt University - Expertise Centre for Digital Media

2. Efficient Transmission of Rendering-Related Data Using the NIProxy Outline Introduction & Motivation Network Intelligence Proxy (NIProxy) –Client Bandwidth Management Considered Networked Application –Rendering Scheme Implementation Evaluation –Experimental Results –Discussion Conclusions 18/03/2008 EuroIMSA20082

3. Efficient Transmission of Rendering-Related Data Using the NIProxy Introduction & Motivation Client downstream bandwidth == scarce commodity –May not suffice to receive all data produced by networked applications ==> Should be managed judiciously ==> Goal = Optimize usage experience Client bandwidth management approaches –Directly integrated in application software Unprofitable from economic point of view –Generic/reusable middleware solution “Network Intelligence Proxy” (NIProxy) 18/03/2008 EuroIMSA20083

4. Efficient Transmission of Rendering-Related Data Using the NIProxy Network Intelligence Proxy Network intermediary (proxy server) Objective = Maximize user Quality of Experience (QoE) (note: QoE != QoS) Approach = Incorporation of context in transportation network –Both network and application awareness Context is exploited to improve data dissemination to clients –Automatic and dynamic traffic management –Multimedia service provision 18/03/2008 EuroIMSA20084

5. Efficient Transmission of Rendering-Related Data Using the NIProxy Client Bandwidth Management using NIProxy Organization of network flows in stream hierarchy –Tree-like structure –Internal nodes : Implement BW distribution Priority WeightData WeightStream Percentage –Leaf nodes : Correspond to actual network flow Real-time : Toggle between discrete BW usage levels Non real-time : Continuous BW usage adaptation 18/03/2008 EuroIMSA20085

6. Efficient Transmission of Rendering-Related Data Using the NIProxy Considered Networked Application 3D Networked Virtual Environment (NVE) User communication : Audio & video chat Advanced rendering scheme –Combines geometric & image-based rendering Geometric rendering: Progressive Meshes (PMs) –Enables progressive transmission IBR: Relief Texture Mapped Objects (RTMOs) –Images with depth-information In terms of visual quality : geom rendering > IBR In terms of complexity: geom rendering > IBR 18/03/2008 EuroIMSA20086

7. Efficient Transmission of Rendering-Related Data Using the NIProxy Considered Networked Application Advanced rendering scheme (continued) –Level of Detail (LoD) manager Selects most suitable representation for 3D objects Considers scene priority, framerate (current/desired), distance to viewer (= model display size), … Approach : PM for nearby, IBR for distant objects –Model representation switching is supported All rendering-related data managed by file server (maintains central model database) –Dissemination of model data to clients needed Objective = quickly present user with initial view In terms of size: geom data > IBR data 18/03/2008 EuroIMSA20087

8. Efficient Transmission of Rendering-Related Data Using the NIProxy Implementation 18/03/2008 Translate requirements into appropriate stream hierarchy structure EuroIMSA20088

9. Efficient Transmission of Rendering-Related Data Using the NIProxy Implementation 18/03/2008 Translate requirements into appropriate stream hierarchy structure EuroIMSA20089

10. Efficient Transmission of Rendering-Related Data Using the NIProxy Implementation 18/03/2008 Translate requirements into appropriate stream hierarchy structure EuroIMSA200810

11. Efficient Transmission of Rendering-Related Data Using the NIProxy Implementation 18/03/2008 Translate requirements into appropriate stream hierarchy structure EuroIMSA200811

12. Efficient Transmission of Rendering-Related Data Using the NIProxy Evaluation Minimalist Experiment 18/03/2008 Limited model count & no real-time traffic Limited client downstream BW (20KBps) EuroIMSA200812

13. Efficient Transmission of Rendering-Related Data Using the NIProxy Evaluation Minimalist Experiment 18/03/2008 Limited model count & no real-time traffic Limited client downstream BW (20KBps) EuroIMSA200813

14. Efficient Transmission of Rendering-Related Data Using the NIProxy Evaluation Realistic Experiment 18/03/2008 Densely populated scene, common BW limit (100 KBps), contention from real- time traffic EuroIMSA200814 IBR pre-loadingVideo trafficContention 3D tx finished IBRGeometry

15. Efficient Transmission of Rendering-Related Data Using the NIProxy Evaluation Findings & Discussion Over-encumbrance of client's network connection at all times prevented –Minimal packet delay and loss –Optimal data reception at client-side NVE requirements captured successfully –Minimize time needed for rendering initial view First stream image-based representation Upgrade gradually with geometric data Contention for client BW coped with –Through use Percentage hierarchy node 18/03/2008 EuroIMSA200815 ==> User QoE improved

16. Efficient Transmission of Rendering-Related Data Using the NIProxy Conclusions Client bandwidth remains scarce and hence requires efficient management NIProxy : Network Intelligence Proxy –Awareness introduction in network NIProxy integration in NVE application –Distribution of rendering-related data –Real-time streaming audiovisual content Exp results show NVE requirements were translated to effective BW distributions –Outcome = Improved user QoE 18/03/2008 EuroIMSA200816

17. Efficient Transmission of Rendering-Related Data Using the NIProxy Thank you for your attention! Any questions?