Application, Network and Link Layer Measurements of Streaming Video over a Wireless Campus Network

Passive & Active Measurement Workshop 05Boston, MA, April 1st, 2005

Feng Li, Jae Chung, Mingzhe Li, Huahui Wu, Mark Claypool, Bob Kinicki

{lif,goos,lmz,flashine,claypool,rek}@cs.wpi.edu

Computer Science DepartmentWorcester Polytechnic Institute

Worcester, MA, 01609 USA

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Outline

• Introduction

• Experimental Methods– Tools and Setup– Experimental Design

• Results and Analysis

• Conclusions and Future work

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Motivation

• Increasingly, deployment of streaming multimedia over wireless LANs– Hardware price decreasing. – Wireless link capacity increasing:

11Mbps(802.11b), 54Mbps(802.11g).– Streaming techniques becoming

mature.

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Objectives

• Correlate performance for– Wireless Link Layer– Network Layer – Application Layer

• Characterize– Streaming Video Parameters

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Outline

• Introduction

• Experimental Methods– Tools and Setup– Experimental Design

• Results and Analysis

• Conclusions and Future work

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WPI Campus Network

WPI Wired Campus Network

WPI Wireless Network

100 M bps

Ethernet

WindowsStreaming Server

Access Point

Access Point

Mobile ClientMobile Client

Mobile Client

Mobile Client

IEEE 802.11g

Layer Tools Performance Measures

Application Media Tracker Frame rate, Frame Lost, Encoding bit rate

Network UDP Ping, Wget Round-Trip time, Packet loss rate, Throughput

Wireless Typeperf, WRAPI Signal Strength, Frame Retries, Capacity.

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Experimental Parameters

• Three access points (AP)– Three AP’s on three different floors in the WPI

CS Department.

• Three different reception locations for each AP.– Good, Fair, Bad based on Windows Wireless

signal strength indicator.

• Experiment period– Winter Break, Dec 23 – 25, Dec 28, 29, 2004

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Experimental Methods

• Each Experiment instance consists of – 1 Initial TCP bulk download– 8 Videos

• 2 Clips: High Motion and Low Motion • 2 Encoding method

– Single Level at 2.5M bps– Multiple Level , 11 levels, max 2.5 M bps.

• 2 Protocols: TCP and UDP

– 1 Final TCP bulk download

• Total: 360 video streaming360 = 3 APs * 3 Locations * 8 videos * 5

repetitions

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Outline

• Introduction

• Experimental Methods– Tools and Setup– Experimental Design

• Results and Analysis

• Conclusions and Future work

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High Level Analysis

TCP Streaming UDP Streaming Total

Multiple Level Video 86 85 171

Single Level Video 89 90 179

Subtotal 175 175 350

Data Collected

• 10 data sets were removed from the 360 video runs due to wireless connection failure.

TCP Streaming UDP Streaming Total

Multiple Level Video 86 + 4 85 + 5 171

Single Level Video 89 + 1 90 179

Subtotal 175 175 350

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Signal Strength Analysis

Fig.2.

Fig.3.

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Wireless Retry Fraction

Figure 8 (modified) : Wireless Retry Fraction for Upstream Traffic

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TCP vs UDP Analysis: Frame Rate

Figure 6: Frame Rate for TCP and UDP Streaming

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TCP vs UDP Analysis : Round Trip Time

Figure 10: Network Round Trip Time for TCP and UDP Streaming

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TCP vs UDP Analysis: Duration

Figure 11: Normalized Playout Duration for TCP and UDP Streaming

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Multiple vs Single Analysis: Frame Rate

Figure 4: Frame Rate for Multiple and Single Level Encoding

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Multiple vs Single Analysis: Encoding Rate

Fig .14 Encoding Bit Rate vs Wireless Link Capacity

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Conclusions

• At Good wireless reception locations:– Nearly all the video clips played out at a

high Frame Rate.– The treatment choices for streaming a

video of multiple or single encoding levels and TCP or UDP protocols do not significantly impact performance.

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Conclusions

• At Bad wireless reception locations:– Multiple level video streams adapt

better than single level streams. – Videos streamed using TCP play out at

a higher average frame rate than the same video streamed using UDP.

– The play out duration for TCP videos is significantly longer than UDP videos.

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Future work

• To develop new application layer techniques to identify and adapt to challenging wireless transmission situations.

• To study the behavior at the AP and the interaction of concurrent clients.

• To concurrently capture burst loss behavior at multiple protocol levels.

• To evaluate other commercial streaming products: Realplayer TM and Quick timeTM player.

Application, Network and Link Layer Measurements of Streaming Video over a Wireless Campus Network

Passive & Active Measurement Workshop 05

Feng Li, Jae Chung, Mingzhe Li, Huahui Wu, Mark Claypool, Bob Kinicki

{lif,goos,lmz,flashine,claypool,rek}@cs.wpi.edu

CS Department at Worcester Polytechnic Institute

Worcester, MA, 01609 USA

Thank You!

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Appendix: Encoding Bit Rate vs Wireless Link Capacity

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TCP vs UDP Analysis: Network Loss Rate

Figure 9: Network Loss Rate for TCP and UDP Stream