Study of Proposed Internet Congestion Control Mechanisms NIST 

 

Mills, et al. Special Publication 500-282 viii 

Table of Contents 

List of Figures xvii 

List of Tables xxvi 

List of Acronyms xxxi 

1 Introduction __________________________________________________________________ 2 

2 Method and Related Work ______________________________________________________ 6 

2.1 Challenge Problem ____________________________________________________ 6 

2.1.1 Current State of the Art _______________________________________ 7

2.1.1.1 Empirical Studies ___________________________________ 7

2.1.1.2 Simulation Studies ___________________________________ 8

2.1.1.3 Analytical Studies ___________________________________ 8 

2.1.2 Proposed Advance in the State of the Art ________________________ 9 

2.2 Potential Approaches __________________________________________________ 9 

2.2.1 Expanded Empirical Studies ___________________________________ 10 

2.2.2 Expanded Simulation Studies __________________________________ 10 

2.2.3 Expanded Analytical Studies ___________________________________ 12 

2.3 Selected Approach ____________________________________________________ 12 

2.4 Hard Problems _______________________________________________________ 13 

2.4.1 Model Scale _________________________________________________ 13 

2.4.2 Model Validation ____________________________________________ 14 

2.4.3 Tractable Analysis ___________________________________________ 14 

2.4.4 Causal Analysis ______________________________________________ 14 

2.4.5 Experiment Selection _________________________________________ 14 

2.5 Selected Solutions and Possible Alternatives _______________________________ 15 

2.5.1 Scale Reduction ______________________________________________ 16 

2.5.2 Sensitivity Analysis and Key Empirical Comparisons ______________ 19 

2.5.3 Statistical Analysis Methods ___________________________________ 21 

2.5.4 Data-Supported Domain Expertise ______________________________ 24 

2.5.5 Domain Expertise and Incremental Design _______________________ 26 

2.6 Conclusions __________________________________________________________ 27 

3 Description of MesoNet _________________________________________________________ 30 

3.1 Model Structure ______________________________________________________ 30 

3.1.1 Model Elements _____________________________________________ 31 

3.1.1.1 Sources ____________________________________________ 31 

3.1.1.2 Receivers __________________________________________ 33 

3.1.1.3 Access Routers ______________________________________ 33 

3.1.1.4 Point-of-Presence Routers ____________________________ 35 

3.1.1.5 Backbone Routers ___________________________________ 35 

3.1.1.6 Backbone Links _____________________________________ 36 

3.1.2 Network Topology ___________________________________________ 36 

3.1.2.1 Four-Tier Structure _________________________________ 38 

3.1.2.2 Heterogeneous Composition ___________________________ 39 

3.1.2.3 Flow Classes ________________________________________ 39 

3.1.2.4 Fixed-Path Routing __________________________________ 39 

3.1.2.5 Simulated Abilene Characteristics _____________________ 40 

3.1.3 Simulated Packets ____________________________________________ 41 

3.1.4 Relating Abstract Time to Real Time ____________________________ 42 

3.2 Model Configuration __________________________________________________ 43 
Study of Proposed Internet Congestion Control Mechanisms NIST 

 

Mills, et al. Special Publication 500-282 ix 

3.2.1 Simulation Control Parameters ________________________________ 43 

3.2.2 Parameters Defining User Behavior _____________________________ 44 

3.2.3 Parameters Adapting Network Topology ________________________ 44 

3.2.4 Parameters Describing Sources and Receivers ____________________ 45 

3.2.5 Parameters Specifying Special Long-Lived Flows _________________ 47 

3.2.6 Parameters for Transport Protocols _____________________________ 49 

3.2.7 Parameters Identifying Monitored Links ________________________ 50 

3.2.8 Reporting Parameter Settings __________________________________ 50 

3.3 Model Measurements _________________________________________________ 50 

3.3.1 General Measurement Regime _________________________________ 51 

3.3.2 Summary Measures __________________________________________ 51 

3.3.3 Aggregate Measures __________________________________________ 52 

3.3.4 Flow-Class Measures _________________________________________ 55 

3.3.5 Long-Lived Flow Measures ____________________________________ 57 

3.3.6 Per-Router Measures _________________________________________ 58 

3.3.6.1 Measurements Common to All Routers _________________ 59 

3.3.6.2 Measurements Unique to Access Routers ________________ 60 

3.3.7 Optional, Link-Level Measures _________________________________ 61 

3.3.8 Augmenting Measures ________________________________________ 61 

3.4 Tracing Flow Behavior ________________________________________________ 63 

3.4.1 Tracing Flow States __________________________________________ 63 

3.4.2 Tracing Packets _____________________________________________ 64 

3.5 Notes on Model Construction with SLX __________________________________ 64 

3.5.1 Configuration File ___________________________________________ 65 

3.5.2 Topology File ________________________________________________ 65 

3.5.3 Model Behavior File __________________________________________ 66 

3.5.3.1 Model Elements _____________________________________ 66 

3.5.3.2 Simulation Control __________________________________ 66 

3.5.3.3 Measurement Buffers ________________________________ 67 

3.5.4 Performance Properties of MesoNet _____________________________ 67 

3.5.4.1 Processing Requirements _____________________________ 69 

3.5.4.2 Memory Requirements _______________________________ 69 

4 Sensitivity Analysis of MesoNet __________________________________________________ 71 

4.1 Method _____________________________________________________________ 73 

4.1.1 Experiment Design ___________________________________________ 73 

4.1.1.1 Identify Factors _____________________________________ 73 

4.1.1.2 Select Number of Levels and Level Settings for Factors ____ 74 

4.1.1.3 Select Specific Combinations to Simulate ________________ 74 

4.1.1.4 Select Responses to Examine __________________________ 76 

4.1.2 Candidate Responses _________________________________________ 77 

4.1.2.1 Responses Characterizing Macroscopic Network Behavior _ 77 

4.1.2.2 Responses Characterizing User Experience ______________ 78 

4.1.3 Correlation Analysis and Clustering ____________________________ 79 

4.1.3.1 Y-Y Scatter Plots ____________________________________ 79 

4.1.3.2 Correlation Computations ____________________________ 80 

4.1.3.3 Combined Matrix Visualization _______________________ 81 

4.1.3.4 Index-Index Plot ____________________________________ 82 

4.1.4 Principal Components Analysis ________________________________ 83 

4.1.5 10-Step Graphical Analysis of Selected Responses _________________ 84 

4.1.6 Other Exploratory Plots and Analyses ___________________________ 87 

4.2 Experiment Design for MesoNet Sensitivity Analysis _______________________ 89 

4.2.1 MesoNet Factors _____________________________________________ 89 

4.2.1.1 Simulation Control Parameters ________________________ 89 

4.2.1.2 Parameters Controlling User Behavior __________________ 90 

4.2.1.3 Parameters Adapting Network Characteristics ___________ 90 
Study of Proposed Internet Congestion Control Mechanisms NIST 

 

Mills, et al. Special Publication 500-282 x 

4.2.1.4 Parameters Altering Properties of Sources and Receivers __ 91 

4.2.1.5 Parameters Controlling Source Startup Pattern __________ 92 

4.2.1.6 Parameters Related to TCP Operation __________________ 93 

4.2.1.7 Summary of Factors Selected for Sensitivity Analysis _____ 93 

4.2.2 Number of Levels and Settings for MesoNet Factors _______________ 94 

4.2.2.1 Two-Level Factor Settings ____________________________ 94 

4.2.2.2 Rationale for (and Ramifications of) Network Factor 

 Settings ____________________________________________ 94 

4.2.2.3 Rationale for (and Ramifications of) User Factor Settings __ 96 

4.2.2.4 Rationale for (and Ramifications of) Source & Receiver 

 Factor Settings ______________________________________ 97 

4.2.2.5 Rationale for (and Ramifications of) Protocol Factor 

 Settings ____________________________________________ 99 

4.2.3 Specific Combinations Simulated _______________________________ 99 

4.3 Experiment Execution _________________________________________________ 100 

4.3.1 Resource Requirements for Simulations _________________________ 100 

4.3.2 Data Collection and Summarization _____________________________ 102 

4.4 Correlation Analysis and Clustering _____________________________________ 104 

4.5 Principal Components Analysis _________________________________________ 108 

4.6 Sensitivity Analysis ___________________________________________________ 111 

4.6.1 Sensitivity Analysis Guided by Correlation Analysis _______________ 111 

4.6.1.1 Congestion-Related Responses _________________________ 112 

4.6.1.2 Delay-Related Responses _____________________________ 115 

4.6.1.3 Responses Related to Macroscopic Throughput __________ 115 

4.6.1.4 Responses Related to Advantaged Flow Classes __________ 118 

4.6.2 Sensitivity Analysis Guided by Principal Components Analysis ______ 120 

4.6.2.1 Congestion _________________________________________ 120 

4.6.2.2 Delay ______________________________________________ 121 

4.6.2.3 Throughput for Advantaged Flows _____________________ 123 

4.6.2.4 Macroscopic Throughput _____________________________ 124 

4.6.3 Summary of Findings from the Sensitivity Analysis ________________ 125 

4.6.3.1 Main Aspects of Model Behavior _______________________ 125 

4.6.3.2 Major Factors Influencing Model Behavior ______________ 127 

4.6.3.3 Factors Exhibiting Little Influence on Model Behavior ____ 129 

4.7 Exploring Effects of Buffer Sizing _______________________________________ 129 

4.7.1 Effects on Delay Variation _____________________________________ 130 

4.7.2 Effects on Other Aspects of Network Behavior ____________________ 131 

4.8 Conclusions __________________________________________________________ 134 

5 Modeling Alternate Congestion Control Mechanisms ________________________________ 137 

5.1 TCP Congestion Control _______________________________________________ 138 

5.1.1 Connection Phase ____________________________________________ 139 

5.1.2 Transfer Phase – Slow Start ___________________________________ 142 

5.1.2.1 Standard Slow Start _________________________________ 142 

5.1.2.2 Limited Slow Start __________________________________ 143 

5.1.2.3 Setting Slow-Start Threshold __________________________ 143 

5.1.3 Transfer Phase – Congestion Avoidance _________________________ 143 

5.1.3.1 Increase Congestion Window after Acknowledgment ______ 144 

5.1.3.2 Decrease Congestion Window after Signaled Loss ________ 144 

5.1.3.3 Decrease Slow-Start Threshold and Reset Congestion 

 Window after Timeout _______________________________ 144 

5.1.3.4 Combined Effects of Slow Start and Congestion Avoidance 145 

5.2 Congestion Avoidance Procedures for Six Alternate Congestion Control 

 Mechanisms _________________________________________________________ 146 

5.2.1 BIC ________________________________________________________ 147 

5.2.1.1 Increase Procedures _________________________________ 148 
Study of Proposed Internet Congestion Control Mechanisms NIST 

 

Mills, et al. Special Publication 500-282 xi 

5.2.1.2 Decrease Procedures _________________________________ 149 

5.2.1.3 Timeout Procedures _________________________________ 149 

5.2.2 CTCP ______________________________________________________ 150 

5.2.2.1 Increase Procedures _________________________________ 151 

5.2.2.2 Decrease Procedures _________________________________ 151 

5.2.2.3 Timeout Procedures _________________________________ 151 

5.2.2.4 Periodic Procedures _________________________________ 151 

5.2.3 FAST ______________________________________________________ 152 

5.2.3.1 Increase Procedures _________________________________ 152 

5.2.3.2 Decrease Procedures _________________________________ 152 

5.2.3.3 Timeout Procedures _________________________________ 154 

5.2.3.4 Periodic Procedures _________________________________ 154 

5.2.4 HSTCP _____________________________________________________ 154 

5.2.4.1 Increase Procedures _________________________________ 155 

5.2.4.2 Decrease Procedures _________________________________ 155 

5.2.4.3 Timeout Procedures _________________________________ 155 

5.2.5 H-TCP _____________________________________________________ 156 

5.2.5.1 Increase Procedures _________________________________ 157 

5.2.5.2 Decrease Procedures _________________________________ 157 

5.2.5.3 Timeout Procedures _________________________________ 157 

5.2.5.4 Periodic Procedures _________________________________ 158 

5.2.6 Scalable TCP ________________________________________________ 158 

5.2.6.1 Increase Procedures _________________________________ 158 

5.2.6.2 Decrease Procedures _________________________________ 159 

5.2.6.3 Timeout Procedures _________________________________ 159 

5.3 Modeling the Transfer Phase in MesoNet _________________________________ 159 

5.3.1 General Data Transfer Procedures ______________________________ 159 

5.3.2 Slow Start __________________________________________________ 161 

5.3.3 Congestion Avoidance ________________________________________ 161 

5.3.3.1 Acknowledgment Procedures __________________________ 161 

5.3.3.2 Negative Acknowledgment Procedures __________________ 161 

5.3.3.3 Periodic Procedures _________________________________ 161 

5.3.3.4 Timeout Procedures _________________________________ 161 

5.4 Verifying Simulated Congestion Control Mechanisms ______________________ 162 

5.4.1 Standard TCP Congestion Control Model ________________________ 163 

5.4.2 Behavior of BIC Congestion Control Model ______________________ 165 

5.4.3 Behavior of CTCP Congestion Control Model ____________________ 166 

5.4.4 Behavior of FAST Congestion Control Model _____________________ 167 

5.4.5 Behavior of HSTCP Congestion Control Model ___________________ 173 

5.4.6 Behavior of H-TCP Congestion Control Model ___________________ 173 

5.4.7 Behavior of Scalable TCP Congestion Control Model ______________ 173 

5.4.8 Summary of Behavior of MesoNet Congestion Control Models ______ 178 

6 Comparing Congestion Control Regimes in a Large, Fast Network ____________________ 183 

6.1 Experiment Design ____________________________________________________ 183 

6.1.1 Simulation Parameters ________________________________________ 185 

6.1.2 Conditions Simulated _________________________________________ 189 

6.1.3 Responses Measured _________________________________________ 190 

6.1.3.1 Measures of Macroscopic Behavior _____________________ 190 

6.1.3.2 Measures of User Experience __________________________ 192 

6.1.3.3 Measures of Buffer Usage _____________________________ 193 

6.1.3.4 Aggregate Measures _________________________________ 194 

6.2 Experiment Execution and Data Collection _______________________________ 195 

6.2.1 Experiment Execution ________________________________________ 195 

6.2.2 Data Collection ______________________________________________ 198 

6.3 Data Analysis Approach _______________________________________________ 199 
Study of Proposed Internet Congestion Control Mechanisms NIST 

 

Mills, et al. Special Publication 500-282 xii 

6.3.1 Cluster Analysis _____________________________________________ 199 

6.3.2 Detailed Analysis of Individual Responses ________________________ 204 

6.3.3 Condition-Response Summary Analysis _________________________ 206 

6.3.4 Data Exploration ____________________________________________ 208 

6.3.4.1 Extrapolating from Time Series _______________________ 208 

6.3.4.2 Seeking Patterns ____________________________________ 212 

6.3.4.3 Investigating Data Subsets ____________________________ 213 

6.3.4.4 Interactive Animation ________________________________ 213 

6.4 Results ______________________________________________________________ 215 

6.4.1 Time Period One (TP1) _______________________________________ 215 

6.4.1.1 Cluster Analysis for TP1 _____________________________ 215 

6.4.1.2 Condition-Response Summary for TP1 _________________ 215 

6.4.1.3 Analysis of Significant Responses for TP1 _______________ 217 

6.4.1.4 Summary of Results for TP1 __________________________ 220 

6.4.2 Time Period Two (TP2) _______________________________________ 220 

6.4.2.1 Cluster Analysis for TP2 _____________________________ 220 

6.4.2.2 Condition-Response Summary for TP2 _________________ 221 

6.4.2.3 Analysis of Significant Responses for TP2 _______________ 223 

6.4.2.4 Summary of Results for TP2 __________________________ 223 

6.4.3 Time Period Three (TP3) ______________________________________ 228 

6.4.3.1 Cluster Analysis for TP3 _____________________________ 228 

6.4.3.2 Condition-Response Summary for TP3 _________________ 228 

6.4.3.3 Analysis of Significant Responses for TP3 _______________ 228 

6.4.3.4 Summary of Results for TP3 __________________________ 234 

6.4.4 Aggregated Responses (Totals) _________________________________ 234 

6.4.4.1 Cluster Analysis for Totals ____________________________ 234 

6.4.4.2 Condition-Response Summary for Totals ________________ 235 

6.4.4.3 Analysis of Significant Responses for Totals _____________ 235 

6.4.4.4 Summary of Results for Totals ________________________ 238 

6.5 Findings _____________________________________________________________ 238 

6.5.1 Finding #1 __________________________________________________ 238 

6.5.2 Finding #2 __________________________________________________ 241 

6.5.3 Finding #3 __________________________________________________ 246 

6.5.4 Finding #4 __________________________________________________ 248 

6.5.5 Tendencies __________________________________________________ 250 

6.6 Conclusions __________________________________________________________ 250 

7 Comparing Congestion Control Regimes in a Scaled-Down Network ___________________ 253 

7.1 Experiment Design ____________________________________________________ 254 

7.1.1 Changes in Robustness Factors and Fixed Factors _________________ 254 

7.1.2 Orthogonal Fractional Factorial Design of Robustness Conditions ___ 255 

7.1.3 Domain View of Robustness Conditions _________________________ 256 

7.2 Experiment Execution and Data Collection _______________________________ 260 

7.3 Data Analysis Approach _______________________________________________ 260 

7.4 Results ______________________________________________________________ 263 

7.4.1 Time Period One (TP1) _______________________________________ 263 

7.4.1.1 Cluster Analysis for TP1 _____________________________ 264 

7.4.1.2 Condition-Response Summary for TP1 _________________ 264 

7.4.1.3 Analysis of Significant Responses for TP1 _______________ 264 

7.4.1.4 Summary of Results for TP1 __________________________ 271 

7.4.2 Time Period Two (TP2) _______________________________________ 272 

7.4.2.1 Cluster Analysis for TP2 _____________________________ 272 

7.4.2.2 Condition-Response Summary for TP2 _________________ 272 

7.4.2.3 Analysis of Significant Responses for TP2 _______________ 272 

7.4.2.4 Summary of Results for TP2 __________________________ 272 

7.4.3 Time Period Three (TP3) ______________________________________ 279 
Study of Proposed Internet Congestion Control Mechanisms NIST 

 

Mills, et al. Special Publication 500-282 xiii 

7.4.3.1 Cluster Analysis for TP3 _____________________________ 279 

7.4.3.2 Condition-Response Summary for TP3 _________________ 279 

7.4.3.3 Analysis of Significant Responses for TP3 _______________ 279 

7.4.3.4 Summary of Results for TP3 __________________________ 279 

7.4.4 Aggregated Responses (Totals) _________________________________ 279 

7.4.4.1 Cluster Analysis for Totals ____________________________ 285 

7.4.4.2 Condition-Response Summary for Totals ________________ 285 

7.4.4.3 Analysis of Significant Responses for Totals _____________ 287 

7.4.4.4 Summary of Results for Totals ________________________ 287 

7.5 Findings _____________________________________________________________ 290 

7.5.1 Finding #1 __________________________________________________ 290 

7.5.2 Finding #2 __________________________________________________ 292 

7.5.3 Finding #3 __________________________________________________ 293 

7.5.4 Finding #4 __________________________________________________ 311 

7.5.5 Tendencies __________________________________________________ 312 

7.6 Conclusions __________________________________________________________ 313 

8 Comparing Congestion Control Regimes in a Heterogeneous Network _________________ 316 

8.1 Experiment Design ____________________________________________________ 317 

8.1.1 Robustness Factors and Fixed Factors ___________________________ 317 

8.1.1.1 Constraints on Flows of Large Size _____________________ 320 

8.1.1.2 Fixed Experiment Factors ____________________________ 322 

8.1.2 Orthogonal Fractional Factorial Design of Robustness Conditions ___ 324 

8.1.3 Domain View of Robustness Conditions _________________________ 325 

8.1.4 Responses Measured _________________________________________ 330 

8.2 Experiment Execution and Data Collection _______________________________ 331 

8.2.1 Computing Macroscopic Responses _____________________________ 333 

8.2.2 Computing User Experience Responses __________________________ 335 

8.3 Data Analysis Approach _______________________________________________ 336 

8.3.1 Analyzing Macroscopic Behavior _______________________________ 336 

8.3.2 Analyzing User Experience ____________________________________ 337 

8.4 Results ______________________________________________________________ 342 

8.4.1 Macroscopic Network Behavior ________________________________ 342 

8.4.1.1 High Initial Slow-start Threshold ______________________ 342 

8.4.1.2 Low Initial Slow-start Threshold _______________________ 347 

8.4.2 Absolute User Experience _____________________________________ 353 

8.4.2.1 High Initial Slow-start Threshold ______________________ 353 

8.4.2.2 Low Initial Slow-start Threshold _______________________ 361 

8.4.2.3 Summary of Differences in Goodput ____________________ 370 

8.4.3 Relative User Experience ______________________________________ 371 

8.4.3.1 High Initial Slow-start Threshold ______________________ 372 

8.4.3.2 Low Initial Slow-start Threshold _______________________ 380 

8.4.3.3 Summary of Differences in Relative Goodput ____________ 388 

8.5 Findings _____________________________________________________________ 389 

8.5.1 Finding #1 __________________________________________________ 390 

8.5.2 Finding #2 __________________________________________________ 390 

8.5.3 Finding #3 __________________________________________________ 391 

8.5.4 Finding #4 __________________________________________________ 391 

8.6 Conclusions __________________________________________________________ 391 

9 Comparing Congestion Control Regimes in a Large, Fast, Heterogeneous Network ______ 395 

9.1 Changes in Experiment Design __________________________________________ 396 

9.1.1 Changes in Robustness Factors and Fixed Factors _________________ 396 

9.1.2 Changes in Orthogonal Fractional Factorial Design of Robustness 

 Conditions __________________________________________________ 397 

9.1.3 Changes in Domain View of Robustness Conditions _______________ 397 
Study of Proposed Internet Congestion Control Mechanisms NIST 

 

Mills, et al. Special Publication 500-282 xiv 

9.1.4 Responses Measured _________________________________________ 400 

9.2 Experiment Execution and Data Collection _______________________________ 400 

9.3 Data Analysis Approach _______________________________________________ 400 

9.4 Results ______________________________________________________________ 401 

9.4.1 Macroscopic Network Behavior ________________________________ 401 

9.4.2 Absolute User Experience _____________________________________ 407 

9.4.3 Relative User Experience ______________________________________ 417 

9.5 Findings _____________________________________________________________ 427 

9.5.1 Finding #1 __________________________________________________ 427 

9.5.2 Finding #2 __________________________________________________ 427 

9.5.3 Finding #3 __________________________________________________ 427 

9.5.4 Finding #4 __________________________________________________ 428 

9.6 Conclusions __________________________________________________________ 428 

10 Conclusions _________________________________________________________________ 431 

10.1 Conclusions about Congestion Control Algorithms ________________________ 431 

10.1.1 Utility and Safety of Alternate Congestion Control Algorithms _____ 431 

10.1.1.1 Increase Rate ______________________________________ 431 

10.1.1.2 Loss/Recovery Processing ____________________________ 432 

10.1.1.3 TCP Fairness ______________________________________ 433 

10.1.1.4 Utility Bounds _____________________________________ 434 

10.1.1.5 Safety ____________________________________________ 435 

10.1.2 Characteristics of Individual Congestion Control Algorithms ______ 436 

10.1.2.1 BIC ______________________________________________ 437 

10.1.2.2 CTCP ____________________________________________ 437 

10.1.2.3 FAST ____________________________________________ 437 

10.1.2.4 FAST-AT _________________________________________ 438 

10.1.2.5 HSTCP ___________________________________________ 438 

10.1.2.6 HTCP ____________________________________________ 439 

10.1.2.7 Scalable TCP ______________________________________ 439 

10.1.3 Recommendations ___________________________________________ 439 

10.1.4 Future Work _______________________________________________ 440 

10.2 Conclusions about Methods ___________________________________________ 440 

10.2.1 Discrete Event Simulation ____________________________________ 441 

10.2.2 Scale Reduction Techniques __________________________________ 441 

10.2.2.1 Model Restriction and Parameter Clustering ___________ 441 

10.2.2.2 Two-Level Experiment Designs _______________________ 442 

10.2.2.3 Orthogonal Fractional Factorial Experiment (OFF) 

 Designs ___________________________________________ 442 

10.2.2.4 Correlation Analysis and Clustering ___________________ 443 

10.2.2.5 Principal Components Analysis (PCA) _________________ 443 

10.2.3 Model Validation Techniques _________________________________ 443 

10.2.3.1 Sensitivity Analysis _________________________________ 444 

10.2.3.2 Key Empirical Comparisons _________________________ 444 

10.2.4 Data Analysis Methods _______________________________________ 445 

10.2.4.1 Ten-Step Graphical Analysis _________________________ 445 

10.2.4.2 Cluster Analysis ____________________________________ 445 

10.2.4.3 Custom Multidimensional Visualizations _______________ 446 

10.2.4.4 Exploratory Multidimensional Interactive Visualization __ 446 

10.2.5 Causality Analysis Methods __________________________________ 447 

10.2.5.1 Principal Components Analysis (PCA) _________________ 447 

10.2.5.2 Detailed Measurements _____________________________ 447 

10.2.5.3 Scientific Method ___________________________________ 448 

10.2.5.4 Exploratory Analysis _______________________________ 448 

10.2.6 Experiment Selection Methods ________________________________ 449 

10.2.6.1 Factor Analysis ____________________________________ 449 
Study of Proposed Internet Congestion Control Mechanisms NIST 

 

Mills, et al. Special Publication 500-282 xv 

10.2.6.2 Domain Expertise __________________________________ 449 

10.2.6.3 Incremental Design _________________________________ 449 

10.2.7 Recommendations ___________________________________________ 450 

10.2.8 Future Work _______________________________________________ 450 

11 Bibliography ________________________________________________________________ 453 

11.1 Fundamentals of Internet Design _______________________________________ 453 

11.2 Standard Transmission Control Protocol (TCP) __________________________ 453 

11.3 Internet Topology ___________________________________________________ 454 

11.4 Internet Traffic Characteristics ________________________________________ 455 

11.5 Internet Technology __________________________________________________ 455 

11.6 Research on Data Transport in High Speed, High Delay Networks ___________ 456 

11.7 Proposed Replacement Congestion Control Mechanisms for the Internet _____ 456 

11.8 Evaluating Internet Congestion Control Mechanisms ______________________ 457 

11.9 Internet Simulation and Models ________________________________________ 458 

11.10 Supporting Software Tools ____________________________________________ 458 

11.11 Supporting Statistical Techniques ______________________________________ 459 

11.12 Empirical Internet Test Beds __________________________________________ 459 

11.13 General Related References ___________________________________________ 460 

11.14 Analytical Internet Models ____________________________________________ 460 

Appendix A Understanding, Improving and Applying Fluid-Flow Models ________________ 463 

A.1 Fluid-flow Approximation Models ______________________________________ 463 

A.1.1 Modeling Many Flows on One Link ____________________________ 465 

A.1.2 Utility of Fluid-flow Approximation Models ______________________ 467 

A.1.3 Limitations of Fluid-flow Approximation Models _________________ 468 

A.2 Applying Fluid-flow Approximation Models to Compare Alternate Congestion 

 Control Algorithms ___________________________________________________ 469 

A.2.1 Computing Response Functions ________________________________ 471 

A.2.1.1 TCP Reno _________________________________________ 471 

A.2.1.2 Cubic TCP _________________________________________ 472 

A.2.1.3 Compound TCP ____________________________________ 475 

A.2.2 Comparing Congestion Control Algorithms ______________________ 477 

A.3 Future Work ________________________________________________________ 481 

Appendix B Computation Requirements: MesoNet vs. Hybrid Model ____________________ 483 

B.1 Experiment Design ___________________________________________________ 483 

B.2 Experiment Execution and Data Collection _______________________________ 488 

B.3 Results _____________________________________________________________ 489 

B.4 Discussion ___________________________________________________________ 489 

B.5 Conclusions _________________________________________________________ 490 

Appendix C Supplementary Sensitivity Analysis Results ______________________________ 493 

C.1 Experiment Design ___________________________________________________ 493 

C.2 Experiment Execution and Data Collection _______________________________ 498 

C.3 Results _____________________________________________________________ 500 

C.3.1 Correlation Analysis _________________________________________ 500 

C.3.2 Principal Components Analysis ________________________________ 502 

C.3.3 Exploratory Analysis of y7-y22 Scatter Plot Bifurcation ____________ 505 

C.3.4 Main Effects Analysis ________________________________________ 505 

C.3.4.1 Congestion-Related Responses ________________________ 507 

C.3.4.2 Delay-Related Responses _____________________________ 510 

C.3.4.3 Responses Related to Macroscopic Throughput __________ 511 

C.3.4.4 Responses Related to Advantaged Flow Classes __________ 512 

C.3.5 Summary of Findings from Sensitivity Analysis __________________ 515 

C.3.6 Exploring Effects of Buffer Sizing ______________________________ 516 
Study of Proposed Internet Congestion Control Mechanisms NIST 

 

Mills, et al. Special Publication 500-282 xvi 

C.4 Discussion ___________________________________________________________ 519 

C.5 Conclusions _________________________________________________________ 521 

Appendix D 10-Step Graphical Analysis Technique ___________________________________ 523 

D.1 Ordered Data Plot ____________________________________________________ 524 

D.2 Multi-factor Scatter Plot ______________________________________________ 525 

D.3 Main Effects Plot _____________________________________________________ 526 

D.4 Interaction Effects Matrix _____________________________________________ 527 

D.5 Block Plots __________________________________________________________ 529 

D.6 Youden Plot _________________________________________________________ 530 

D.7 |Effects| Plot _________________________________________________________ 531 

D.8 Half-Normal Probability of |Effects| _____________________________________ 532 

D.9 Cumulative Residual Standard Deviation Plot ____________________________ 533 

D.10 Contour Plot of Two Dominant Factors __________________________________ 533