Effective and Resource-Efficient Multimedia Communication Using the NIProxy Maarten Wijnants and Wim Lamotte Hasselt University - Expertise Centre for

Effective and Resource-Efficient Multimedia Communication Using the NIProxy

Effective and Resource-Efficient Multimedia Communication

Using the NIProxy

Maarten Wijnants and Wim LamotteHasselt University - Expertise Centre for Digital Media


Introduction and Motivation

• Increasing interest in multimedia services such as VoIP, real-time videostreaming, …– Require high, guaranteed performance levels

from communication network– Raise need for network resource managementBoth issues often not addressed/supported by

current-gen networks

• Networks faced with growing diversity, e.g.– Proliferation of new networking technologies

and protocols– Heterogeneity in client device space

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Introduction and Motivation

• Next-gen networks should– Provide adequate, resource-efficient support

for multimedia communication– Be able to successfully cope with heterogeneity

• Design/deploy from scratch: Expensive!• Extend functionality current networks with

next-gen features: Cost-efficient (reuse)!• NIProxy: Network intermediary

– Enhances IP-based networks with functionality to improve MM communication

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Outline

• Introduction and Motivation• Network Intelligence Proxy (NIProxy)

– Objectives and methodology– Support for upstream/outbound network traffic

• Practical Use Case: Outbound Video Transcoding

• Evaluation of Proposed NIProxy Extensions – Experimental Setup– Experimental Results

• Conclusions

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Network Intelligence Proxy (NIProxy)

• Goal = Improve user Quality of Experience– Note: QoE != Quality of Service (QoS) !

• Approach = Incorporate intelligence/ awareness in transportation network– Network- as well as application-related context

• Info about transportation network state (probing)• Knowledge of the networked application

• Intelligence enables NIProxy to implement effective/efficient MM data dissemination– Network traffic shaping & MM service provision Complementary techniques, interoperable

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Network Intelligence Proxy (NIProxy)

• NIProxy is under continuous development– Traffic shaping & service provision previously

confined to downstream/inbound direction– Now extended to upstream/outbound direction

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Downstream Upstream

Processing location

Near end of MM stream’s network traversal

Beginning of MM stream’s network traversal

Flow sourceDestined for NIProxy client

Emitted by NIProxy client


Practical Use Case: Outbound Video Transcoding

• Enables NIProxy to on-the-fly reduce bitrate of outbound video streams at early stage of video flow network traversal

– Decreases temporal resolution & increases compression ratio (larger quantization step)

• Mode of operation– In = Outbound video at original quality– Out = Original version or transcoded variant– Based on video source’s upstream bandwidth

distribution strategy devised by NIProxy– Unnecessary transcoding operations eliminated

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Practical Use Case: Outbound Video Transcoding

• Exemplifies interoperation possibilities between traffic shaping & service provision and the positive implications it entails– Service introduces new type of network flow– Ensures it is represented in video source’s

upstream network traffic shaping scheme– Once incorporated, it is considered during

management of source’s upstream BW capacity– NIProxy’s network traffic shaping scheme

subsequently dictates outbound video transcoding decisions

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Evaluation

• Goal = Investigate added value outbound network traffic shaping & service provision

• Experimental setup: Simulation of unicast MM streaming scenario

• Involved several (distributed) entities– Single streaming server, multiple clients– NIProxy: Shaped server emitted traffic– WAN BW broker: Managed BW capacity of the

network backbone• Determined amount of backbone BW the streaming

server could maximally consume (e.g. SLA-based)

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Evaluation

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MM server & clients deployed in separate access networks Server’s outbound network traffic consumed backbone bandwidth

NIProxy deployed at end of server’s access connection Adapted/shaped server’s outbound network traffic before it reached the WAN


Evaluation: Minimalist Experiment

• MM server streamed video fragment + audio stream to single client– NIProxy responsible for apportioning WAN BW

reserved for MM server over these 2 flows

• Fluctuations in server WAN BW capacity– Conceptually partitioned exp in # intervals

• Client preferred audio over video– Server made NIProxy aware of this app-related

information was taken into account when shaping the server’s upstream BW

• NIProxy used outbound video transcoding

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Evaluation: Minimalist Experiment

Dashed vertical lines separate experiment intervals

Bandwidth consumption:TV < audio < OV

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Analysis: WAN transmission of audio flow prioritized throughout entire experimentAnalysis: BW left unused by audio employed to implement video streaming at highest quality possible


Evaluation: More Realistic Experiment

• Multiple simultaneous clients, each requested one video fragment from server

• Steady server WAN BW capacity• Contracts between MM server and clients

– Distinction regular/premium clients– Premium users should receive improved service

• Dynamic aspect: Arrival/departure of clients during experiment execution– Initiation/suspension outbound flows at runtime– Conceptually partitioned exp in # intervals

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Evaluation: More Realistic Experiment

Dashed vertical lines separate experiment intervals

Small transition period at start 4th interval (non-optimal BW distr)

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Analysis: Client contracts were observed (server’s premium users received preferential treatment)


Evaluation:Experimental Findings

• MM server respected its WAN BW capacity– E.g. no SLA contract violation– Contributed to WAN stability and performance

predictability positive influence on user QoE

• NIProxy attempted to maximize the utility of the upstream BW allocated to server– WAN BW partitioned as intelligently/effectively as

possible over server’s set of outbound flows• Guided by app-awareness; Positively affected user QoE

• QoE-improvement collaboration beneficial– Lower-quality WAN video streaming possible

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Conclusions

• Popularity multimedia streaming rising– Support for effective and resource-efficient

multimedia network communication required

• We therefore propose the NIProxy– Enhances IP-based network with traffic shaping

and MM service provision functions• Downstream/inbound as well as upstream/outbound

• Experimental evaluation demonstrated NIProxy benefits– MM capabilities of networks are improved– Positive impact on experience witnessed by users

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Thank you for your attention!Any questions?

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Effective and Resource-Efficient Multimedia Communication Using the NIProxy Maarten Wijnants and Wim Lamotte Hasselt University - Expertise Centre for