Efficient Transmission of Rendering-Related Data Using the NIProxy

Efficient Transmission of Rendering-Related Data Using the NIProxy

Maarten WijnantsTom JehaesPeter Quax

Wim LamotteHasselt University - Expertise Centre for Digital Media

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

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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)

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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

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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

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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

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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

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Implementation

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• Translate requirements into appropriate stream hierarchy structure

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Efficient Transmission of Rendering-Related Data Using the NIProxy

Implementation

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• Translate requirements into appropriate stream hierarchy structure

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Efficient Transmission of Rendering-Related Data Using the NIProxy

Implementation

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• Translate requirements into appropriate stream hierarchy structure

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Efficient Transmission of Rendering-Related Data Using the NIProxy

Implementation

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• Translate requirements into appropriate stream hierarchy structure

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Efficient Transmission of Rendering-Related Data Using the NIProxy

EvaluationMinimalist Experiment

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• Limited model count & no real-time traffic• Limited client downstream BW (20KBps)

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Efficient Transmission of Rendering-Related Data Using the NIProxy

EvaluationMinimalist Experiment

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• Limited model count & no real-time traffic• Limited client downstream BW (20KBps)

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EvaluationRealistic Experiment

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• Densely populated scene, common BW limit (100 KBps), contention from real-time traffic

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IBR pre-loading Video trafficContention 3D tx finishedIBRGeometry

Efficient Transmission of Rendering-Related Data Using the NIProxy

EvaluationFindings & 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

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==> User QoE improved

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

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Efficient Transmission of Rendering-Related Data Using the NIProxy

Thank you for your attention!Any questions?