COS561 Final Project: Reimplementing Continuous In-Network Round-Trip Time Monitoring with DART

Group Members: Haichen Dong (hd5234), Deyuan (Mike) He (dh7120), Ann Zhou (az6922) and Kaiqu Liang (kl2471)

Keywords: RTT Measurement, Simulation

Dependencies

We have tested our implementation on macOS 12.6. To install Python dependencies:

python3 -m pip install -r requirements.txt

In addition to these dependencies, our simulation requires Wireshark in order to parse trace files.

macOS

Install Homebrew first, then:

brew install wireshark

Linux

sudo apt update && sudo apt-get install wireshark

Windows

Available at Wireshark official site.

If the installation and path configuration is properly done, you will be able to run tshark through command line tools.

Reproducing Plots

plot.py under tests directory can be used to reproduce figures in our report.

Specifically, to run simulation on a trace file, first place the pcap file under data directory, then run plot.py with --dataset <name of pcap>

For instance, to run simulation with capture_1.pcap, simply execute

$ python3 plot.py --dataset capture_1

By default, the capacity of Range Table and Packet Table is infinite. plot.py accepts command line arguments to run customized settings. Available options and values are:

• --dataset <str>: default "test"; name of the trace file under data directory to run simulation on;
• --outgoing-only: default False; if the flag is passed, all SEQ packets that are not sent by host with IP address starting with "10." will be filtered (as the tracing was done on computer connected to the Princeton network); this option helps filtering out "short legs" of RTT measurements since we are running packet tracing on the end host instead of on some intermediate switches.
• --total-size <nat>: default 20001. The total capacity (number of entries can be held) in Range Table and Packet Table.
• --packet-tracker-size <nat>: default 10001. The capacity of Packet Table; this number should be less than the value passed to --total-size; the size of Range Table will be computed accordingly.
• --pt-policy <str>: default dart; the eviction policy for the Packet Tracker. By default, it uses Lazy Eviction introduced in the Dart paper. In addition, as an extenstion, we provide two additional tunable eviction policies;
  • prob: Keep old/new entries with some probability without any recirculation (see Dart paper or our report for "recirculation").
  • prob-recirc: Recirculation first, then keep the recirculated entry with some probability
• --rt-policy <str>: default "keep-new". the eviction policy of Range Table. Options are
  • keep-new: Always keep the new entry
  • keep-old: Always keep the old entry
  • prob: Keep the old entry with some probability (configurable through --rt-eviction-prob <float>)
  • refined: Keep the old entry if the number of in-flight packet is above some threshold, which is configurable through --in-flight-threshold <int>
• --rt-evcition-prob <float>: default 0.5; the probability of keeping the old entry upon a Range Table hash collision. This option is effective if --rt-policy is set to prob.
• --in-flight-threshold <int>: default 3. The eviction threshold of old entries in Range Table. This option is effective if --rt-policy is set to refined.

Reproduce Figures

We provide commands we executed to generate figures in our report. Specifically:

Reproduce Results in Extension

First, cd tests && mkdir figures. Figure 9 and 11 can be reproduced by running

python3 plot.py --dataset capture_bili_20k

Unbiased RTT Measurements

CDF plots

python3 ext_bias_cdf.py --dataset smallFlows --packet-tracker-size {32,256}

python3 ext_bias_cdf.py --dataset capture_4 --outgoing-only --packet-tracker-size 16

Count calculation

python3 ext_bias_count.py --dataset capture_4 --outgoing-only --packet-tracker-size {64,128,256,512,1024,2048}

Collection error calculation

python3 ext_bias_error.py --dataset smallFlows --packet-tracker-size 15000

Switch Memory Allocation

Count calculation

python3 ext_memory_count.py --dataset smallFlows --total-size 15000