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Characterization by Measurement of a CDMA 1x EVDO Network. Mark Claypool, Robert Kinicki, William Lee, Mingzhe Li , and Gregory Ratner CS Department at Worcester Polytechnic Institute Worcester, MA 01609 USA. Presenter: Mingzhe Li [lmz@cs.wpi.edu] Wireless Internet Conference (WICON’06)
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Characterization by Measurement of a CDMA 1x EVDO Network Mark Claypool, Robert Kinicki, William Lee, Mingzhe Li, and Gregory Ratner CS Department at Worcester Polytechnic Institute Worcester, MA 01609 USA Presenter: Mingzhe Li [lmz@cs.wpi.edu] Wireless Internet Conference (WICON’06) Boston, Massachusetts, August 2006
Motivation • EVDO 3G cellular data networks • Provides more bandwidth • More applications: • Throughput sensitive • Latency sensitive • Multimedia streaming • Current research of cellular data network performance • Theoretical analysis and simulations • Measurements studies • 2G/2.5G networks • Focus on throughput • Few latency measurements and bandwidth estimations • We need more characterization on EVDO networks. WICON’06 – Boston, Massachusetts
Introduction • Measurement based characterization of EVDO network • TCP throughput • Round trip time • Loss rate • Bandwidth estimation • Gauge the ability of EVDO to support the QoS of a range of applications WICON’06 – Boston, Massachusetts
Outline • Introduction • Methodology • Testbed • Tools • Experiment Design • Analysis • Conclusion and future work WICON’06 – Boston, Massachusetts
Testbed 50 Mbps uplink Measure downlink network to the laptop Sierra Wireless Aircard 580 PCMCIA EVDO Network Card Gnu Linux kernel 2.6.11 WICON’06 – Boston, Massachusetts
Tools WICON’06 – Boston, Massachusetts
Experimen design • Each test includes: • Measure wireless signal strength • Wget downloads 20 Mbyte file • Ping server 100 times • npath: capacity estimation • Packet pairs length: 25 packets • Packet size: 1472, 1200, 1000, and 800 bytes • Repeat 30 times for each packet size • Each test takes 12 minutes in total • Run every 30 minutes for a week • November 28, 2005 to December 4, 2005 WICON’06 – Boston, Massachusetts
Outline • Introduction • Methodology • Testbed • Tools • Experimental Desgin • Analysis • Conclusion and future work WICON’06 – Boston, Massachusetts
Analysis • Data collected • 48 runs each day for 7 days • All tests with excellent signal strength • -90 to -83 dBm • TCP throughput: tcpdump and tcptrace • RTT and packet loss: ping • Network capacity: npath. • Analysis focus • Week day: Wednesday November 30, 2005 • Weekend: Saturday December 3, 2005 WICON’06 – Boston, Massachusetts
TCP Throughput (cont.) • TCP throughput lower than theoretically EVDO networks • No visual correlation between throughput and the time of day • Satisfactory for most Internet applications WICON’06 – Boston, Massachusetts
TCP Throughput • TCP throughput are consistent between tests • Slightly higher TCP throughput for weekend WICON’06 – Boston, Massachusetts
Round trip time of a weekday • Average RTT are consistent between tests • Maximum RTT vary greatly. • No visual correlation between RTT and the time of day. WICON’06 – Boston, Massachusetts
CCDF of RTT • Median RTT 200ms is too high for interactive applications. • Maximum RTT around 1 second can seriously Impact the performance of interactive applications. WICON’06 – Boston, Massachusetts
Bandwidth Estimation Tests of a weekday • Median of estimated bandwidth is consistent • 5th percentile of estimated bandwidth varies. WICON’06 – Boston, Massachusetts
Bandwidth Estimation (cont.) Tests for weekday and weekend at 5:30pm • Bandwidth estimations are consistent. • Only a small percentage of packet pairs get low estimatiions WICON’06 – Boston, Massachusetts
Summary and Conclusion • 3G EVDO network provides higher throughput than 2G/2.5G cellular networks • The high RTT may impact the performance of interactive applications • Bandwidth estimations are consistent, suggesting packet pairs are sufficient for bandwidth estimation. • Neither throughput, round-trip time, nor bandwidth estimation correlates with time of day or the day of the week. WICON’06 – Boston, Massachusetts
Future work • More Characterizations • Mobility • Poor signal quality • Variable traffic load • Comparison with other cellar networks • Application performance • Interactive applications (games, VoIP) • Multimedia streaming applications WICON’06 – Boston, Massachusetts
Characterization by Measurement of a CDMA 1x EVDO Network Mark Claypool, Robert Kinicki, William Lee, Mingzhe Li, and Gregory Ratner CS Department at Worcester Polytechnic Institute Worcester, MA 01609 USA Presenter: Mingzhe Li [lmz@cs.wpi.edu] Wireless Internet Conference (WICON’06) Boston, Massachusetts, August 2006