Path Discovery Mechanism/Analysis

This page is dedicated to the PDM-analysis tool, a small python script that takes a pcap file as input and outputs statistics on the Path Discovery Mechanism.

The PDM-analysis tool

Requirements

• The PDM-analysis tool requires the stats.py module (which requires the pstat.py module).

• You also need wireshark on the box (the script uses tshark to decode the file). If you want to decode mesh frames you will need the mesh patch. No other dependencies.

Usage

Just make the script executable and fire it:

./PDM-Analysis.py -f <pcap_file> [--no-fcs]

Options:

 -h, --help            show this help message and exit
 -f PCAPFILE, --pcap-file=PCAPFILE
                       Capture dump
 -t TEXTFILE, --text-file=TEXTFILE
                       Capture already converted/filtered
 --no-fcs              don't check if frames have bad crc

• The input file (PCAPFILE) is a tcpdump capture file (captured by tcpdump, wireshark or any other compatible tool)
  • Radiotap header must be present (for the script needs the tx datarate)
  • If your capture does not provide Frame CheckSum (this is the case of the captures from XOs) you must provide the flag --no-fcs
  • By default only frames with good FCS will be computed
• The script generates a temporary file in the local directory named <caprute file>.tmp2
  • This file can be used instead of the original pcap file (using the -t option). This is meant to save processing time if you just want to generate the same report later.
  • The .tmp3 file can be safely removed

The Report

The PDM-Analysis tool will generate a report like the following:

------------------------------------------------------------------------
ROUTE DISCOVERY REPORT (for ../route_exp/captures/10s-mcastping-1.pcap)
------------------------------------------------------------------------
Captured route discovery frames: 14152 [RREQs 12936 (91.41%) RREPs 1141 (8.06%) RERRs 75 (0.53%)]
Route discovery clusters: 852
Average # of frames captured per cluster: 16.52 (stdev = 11.57) [RREQs 15.18, RREPs 1.34, RERRs 0.09]
Replied requisitions (with any rrep captured): 509 (59.00%)
Completed requisitions (with final rrep captured): 158 (18.00%)

RREQs:
By Hop Count: 1: 2165 (16.74%) 2: 4449 (34.39%) 3: 3354 (25.93%) 4: 2280 (17.63%) 5: 688 (5.32%) 
By Datarate: 54: 2374 (18.35%) 36: 2470 (19.09%) 11: 3991 (30.85%) 1: 4101 (31.70%) Unknown: 0 (0.00%) 

RREPs:
By Hop Count: 1: 93 (8.15%) 2: 362 (31.73%) 3: 478 (41.89%) 4: 180 (15.78%) 5: 28 (2.45%) 
Estimated % of multihop paths: 34.26%

First RREP elapsed time (ms): 62.27 (stdev = 35.94) MIN: 14.87 MAX: 183.31
Route acquisition time (ms): 80.74 (stdev = 50.73) MIN 14.87 MAX 263.99
Route discovery lifespan (ms): 94.71 (stdev = 57.99) MAX 263.99
RREQ distribution for 1 hop(s) (ms): mean = 11.02 (stdev = 24.53) MIN: 0.00 MAX: 189.35
RREQ distribution for 2 hop(s) (ms): mean = 34.07 (stdev = 38.90) MIN: 1.69 MAX: 232.48
RREQ distribution for 3 hop(s) (ms): mean = 52.19 (stdev = 40.12) MIN: 4.94 MAX: 227.01
RREQ distribution for 4 hop(s) (ms): mean = 64.19 (stdev = 39.30) MIN: 10.75 MAX: 194.59
RREQ distribution for 5 hop(s) (ms): mean = 82.54 (stdev = 42.35) MIN: 18.09 MAX: 189.81

PDM Airtime (ms): 5778.6543
PDM Activity Interval (s): 68.53
PDM Airtime %: 8.43

Participants: 10

00:17:c4:05:2c:ae: FWD 1518             ORIGIN 65 => 1309               TARGET 65 => 1199
00:17:c4:05:23:3a: FWD 1475             ORIGIN 61 => 1217               TARGET 83 => 1325
00:17:c4:0c:e8:eb: FWD 1307             ORIGIN 145 => 2205              TARGET 82 => 1463
00:17:c4:02:2f:59: FWD 1325             ORIGIN 127 => 1823              TARGET 91 => 1711
00:17:c4:05:27:98: FWD 1691             ORIGIN 149 => 1968              TARGET 78 => 1351
00:17:c4:05:23:02: FWD 1080             ORIGIN 43 => 874                TARGET 109 => 1615
00:17:c4:03:57:1b: FWD 1357             ORIGIN 60 => 1006               TARGET 81 => 1361
00:17:c4:05:2a:79: FWD 1525             ORIGIN 68 => 1217               TARGET 98 => 1701
00:17:c4:03:56:e0: FWD 1477             ORIGIN 67 => 1264               TARGET 83 => 1121
00:17:c4:05:27:a3: FWD 1397             ORIGIN 67 => 1194               TARGET 82 => 1230