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Data File Formats

The folders raw and data contain captured bitrate traces.

Capturing traces

Traces can be captured with collect.sh. This script restarts the driver, starts a packet-spewing script, captures a trace, and kills the packet source. It has three arguments: an IP address to spew packets at, a file name to write the trace to, and how long to record the trace for. For example

./collect.sh 10.0.0.1 test 60

would capture a 60-second trace to raw/test.trace, while sending a deluge of packets toward 10.0.0.1.

Files raw/*.trace

These are directly captured from the kernel, with newer versions; they have one record per line, such as:

Last(2630707680) took 5135412 ns / 20 tries with rate 22 at 26000(24800) kbps [1]

There are six fields here:

  • A unique identifier based on the start time for transmission
  • The time it took to transmit the packet, in nanoseconds
  • The number of tries it took to transmit it (including the successful transmission), up to 20.
  • The identifier for the rate
  • The rate's kilobits per second
  • The rate's kilobits of payload per second; this elides the overhead of FEC and physical-layer headers.
  • The line's index in the internal kernel buffer; if this ever surpasses about 30, we might be missing records.

The util/munge.py script should be used to transform these files for the simulator, and really for any other purpose at all.

There are also sanity-check lines like

0:46 1:323 2:5 3:9 4:13 5:76 6:169 7:739 8:228 9:100 10:290 11:3

These are ignored by the munger, but if any numbers get appreciably big (compared to the range of an unsigned int), there may be problems.

Files data/*.dat

These files are converted from the raw2/*.trace files into Python trace dumps. They're best read with:

eval(open(file_name, "rt").read())

Each file contains a tuple, with three entries: the start time of the first packet, the data arrays, and the start time of the last packet. The data array has a list of tuples for each rate; thus, it is a list of 12 lists.

Each list of tuples has tuples of three elements: the send time, whether or not the packet succeeded, and how long the transmission took. The tuples are ordered by send time.