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Wireless InternetPerformance Research

Carey WilliamsoniCORE Professor

Department of Computer ScienceUniversity of Calgary

www.cpsc.ucalgary.ca/~careycarey@cpsc.ucalgary.ca

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Internet Protocol Stack Application: supporting network

applications and end-user services FTP, SMTP, HTTP, DNS, NTP

Transport: end to end data transfer TCP, UDP

Network: routing of datagrams from source to destination IPv4, IPv6, BGP, RIP, routing protocols

Data Link: hop by hop frames, channel access, flow/error control PPP, Ethernet, IEEE 802.11b

Physical: raw transmission of bits

Application

Transport

Network

Data Link

Physical

001101011...

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The Wireless Web

The emergence and convergence of these technologies enable the “wireless Web” the wireless classroom the wireless workplace the wireless home

My iCORE mandate: design, build, test, and evaluate wireless Web infrastructures

Holy grail: “anything, anytime, anywhere” access to information (when we want it, of course!)

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Research Interests

Wireless Internet Technologies MAC Protocol Design Network Traffic Measurement Workload Characterization Traffic Modeling Network Simulation Web Performance

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Wireless Internet Technologies Mobile devices (e.g., notebooks, laptops,

PDAs, cell phones, wearable computers) Wireless network access

Bluetooth (1 Mbps, up to 3 meters) IEEE 802.11b (11 Mbps, up to 100 meters) IEEE 802.11a (55 Mbps, up to 20 meters)

Operating modes: Infrastructure mode (access point) Ad hoc mode

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Example: Infrastructure Mode

Carey

Internet

Access Point (AP)

cnn.com

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Example: Ad Hoc Mode

Multi-hop “ad hoc” networking

Carey

Sean

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Example: Ad Hoc Mode

Multi-hop “ad hoc” networking

Carey

Sean

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Example: Ad Hoc Mode

Multi-hop “ad hoc” networking

Carey

Sean

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Example: Ad Hoc Mode

Multi-hop “ad hoc” networking

Carey

Sean

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MAC Protocol Design

Identify performance problems in wireless Medium Access Control (MAC) protocols

Examples: IEEE 802.11b WLANs Unfairness problems [Xiao MSc 2004] Effects of node mobility [Bai 2004] “Bad Apple” phenomenon [Cao 2004] TCP on multi-hop ad hoc networks [Gupta

2004] Multi-channel MAC protocols [Kuang 2004] Multi-rate multi-channel protocols [Wu 2005]

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Network Traffic Measurement

Collect and analyze packet-level traces from a live network, using special equipment

Process traces, statistical analysis Diagnose performance problems

(network, protocol, application)101101

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Example: tcpdump Trace0.000000 192.168.1.201 -> 192.168.1.200 60 TCP 4105 80 1315338075 : 1315338075 0 win: 5840 S0.003362 192.168.1.200 -> 192.168.1.201 60 TCP 80 4105 1417888236 : 1417888236 1315338076 win: 5792 SA0.009183 192.168.1.201 -> 192.168.1.200 52 TCP 4105 80 1315338076 : 1315338076 1417888237 win: 5840 A0.010854 192.168.1.201 -> 192.168.1.200 127 TCP 4105 80 1315338076 : 1315338151 1417888237 win: 5840 PA0.014309 192.168.1.200 -> 192.168.1.201 52 TCP 80 4105 1417888237 : 1417888237 1315338151 win: 5792 A0.049848 192.168.1.200 -> 192.168.1.201 1500 TCP 80 4105 1417888237 : 1417889685 1315338151 win: 5792 A0.056902 192.168.1.200 -> 192.168.1.201 1500 TCP 80 4105 1417889685 : 1417891133 1315338151 win: 5792 A0.057284 192.168.1.201 -> 192.168.1.200 52 TCP 4105 80 1315338151 : 1315338151 1417889685 win: 8688 A0.060120 192.168.1.201 -> 192.168.1.200 52 TCP 4105 80 1315338151 : 1315338151 1417891133 win: 11584 A0.068579 192.168.1.200 -> 192.168.1.201 1500 TCP 80 4105 1417891133 : 1417892581 1315338151 win: 5792 PA0.075673 192.168.1.200 -> 192.168.1.201 1500 TCP 80 4105 1417892581 : 1417894029 1315338151 win: 5792 A0.076055 192.168.1.201 -> 192.168.1.200 52 TCP 4105 80 1315338151 : 1315338151 1417892581 win: 14480 A0.083233 192.168.1.200 -> 192.168.1.201 1500 TCP 80 4105 1417894029 : 1417895477 1315338151 win: 5792 A0.096728 192.168.1.200 -> 192.168.1.201 1500 TCP 80 4105 1417896925 : 1417898373 1315338151 win: 5792 A0.103439 192.168.1.200 -> 192.168.1.201 1500 TCP 80 4105 1417898373 : 1417899821 1315338151 win: 5792 A0.103780 192.168.1.201 -> 192.168.1.200 52 TCP 4105 80 1315338151 : 1315338151 1417894029 win: 17376 A0.106534 192.168.1.201 -> 192.168.1.200 52 TCP 4105 80 1315338151 : 1315338151 1417898373 win: 21720 A0.133408 192.168.1.200 -> 192.168.1.201 776 TCP 80 4105 1417904165 : 1417904889 1315338151 win: 5792 FPA0.139200 192.168.1.201 -> 192.168.1.200 52 TCP 4105 80 1315338151 : 1315338151 1417904165 win: 21720 A0.140447 192.168.1.201 -> 192.168.1.200 52 TCP 4105 80 1315338151 : 1315338151 1417904890 win: 21720 FA0.144254 192.168.1.200 -> 192.168.1.201 52 TCP 80 4105 1417904890 : 1417904890 1315338152 win: 5792 A

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Example:TELUS Mobility Project Data Template and Example – XYZ Platform

Code Definition==== ==========

20 FSCH Data Rate 21 FSCH Data Burst Start Time 22 FSCH Data Burst End Time 200 FSCH Active Set Report Time 21x FSCH Active Set Cell ID ('x' is a number) 22x FSCH Active Ste Sector ID ('x' is a number) 30 RSCH Data Rate 31 RSCH Data Burst Start Time 32 RSCH Data Burst End Time 300 RSCH Active Set Report Time 31x RSCH Active Set Cell ID ('x' is a number) 32x RSCH Active Ste Sector ID ('x' is a number) 40 FCH Data Start Time 41 FCH Data End Time 100 FCH Active Set Report Time 11x FCH Active Set Cell ID ('x' is a number) 12x FCH Active Ste Sector ID ('x' is a number) 50 IMSI 60 Frequency 70 SID

50 00000604842178151 0x804ce0401aa8966670 1642260 38440 2004041375333.68041 2004041375443.020200 2004041375337.940211 32221 320 1621 2004041375338.20022 2004041375339.20020 421 2004041375357.86022 2004041375357.88020 1621 2004041375371.72022 2004041375372.700

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Workload Characterization

Try to understand the salient features of network, protocol, application, and user behaviour on the Internet

Example: Web server workloads [Arlitt96] Zipf-like document referencing behaviour Lots of “one-time” referencing of documents Heavy-tailed file size distributions Self-similar network traffic profile Session duration and call arrival process

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Traffic Modeling Construct programs and statistical models

that capture the empirically-observed network traffic behaviours

Allows flexible, controlled, repeatable generation of workloads for experiments

Examples: Web client workload model MPEG compressed video model Self-similar Ethernet LAN traffic model WebTraff GUI: Web proxy workload generator

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Example:Web Workload Generation

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Network Simulation

Use computer simulation to study the packet-level behaviour of the Internet, its protocols, its applications, and its users

Examples: Improving Web performance over ADSL Understanding the effects of user mobility on

Mobile IP routing and protocol performance Studying the design, scalability, and

performance of Web server and Web proxy caching architectures

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Web Performance

Explore techniques to improve the performance and scalability of the Web

Examples: Clustered Web servers Load balancing policies Web prefetching strategies Web proxy caching architectures Improvements to HTTP and TCP protocols

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Web Server

Client 1

Client 2

Client 3

Client C

...

Example:Web Server Benchmarking

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Summary Wireless Internet Performance Lab (UofC) Experimental Laboratory for Internet

Systems and Applications (UofS/UofC,CFI) iCORE Research Team:

Five full-time research staff (Web, perf. eval., simulation, wireless, traffic modeling, network measurement) plus 8 graduate students

Research Collaborations: UofC, UofA, UofS, TRLabs, CS/ECE HP, TELUS Mobility, SaskTel, Nortel…

Industrially-relevant experimental research on network protocol performance