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The pdx/vwave dataset (v. 2009-07-04)  >  the wlan_nano traceset

There are 6 traces in this traceset
last modified
short description

Supplementary information for pcap traces of wireless LAN traffic around Portland, Oregon using a commercial sniffer VWave.


This traceset contains supplimentary information for the corresponding pcap files in pdx/vwave/wlan_pcap, which are six wireless LAN traffic traces around Portland, Oregon, collected using a commercial sniffer VWave which has a nano-second time resolution.

reason for most recent change
the initial version
release date
date/time of measurement start
date/time of measurement end
network type
802.11 infrastructure

These traces were collected using a VeriWave WT20 Appliance which was kindly loaned to us by the folks at VeriWave

The WT20 hardware consists of two 802.11 reference radios, real-time linux, and two processors. The WT20 provides nanosecond resolution timestamps and it logs the time when it began seeing a frame and the time when the frame finished arriving. We are using Veriwave WT20 in a somewhat novel way. It listens with two radios simultaneously on the same channel, recording frames to a per-radio, 256 MB, ring-buffer. The The WT20's firmware will discard any frames received with a signal less than -75 dBm, but the rest (Data and Management, but not Control) are logged without any scrubbing. A tclsh script, running on a laptop connected to the WT20 (via ethernet), grabs the contents of this ring-buffer from each radio in-turn, every 10 seconds. This data is dumped as a VWR file, a proprietary Veriwave file format, and then converted to a libpcap file on the fly. At the end of a 4 hour capture we have 1440 files which are stitched together using a program we have developed for this purpose (after finding that existing tools like mergecap and tcpslice either contained bugs or didn't work with 802.11 traces).

These traces are the result of the additional data contained in the VWR files and not in the pcap files. We used a tool ("log_dump") provided to us as a binary by VeriWave to extract this information, a custom script to parse the output, and then another custom script to stich the many small files together time-wise (omitting redundant portions).

 the pdx/vwave/wlan_nano/psu-cs trace
 the pdx/vwave/wlan_nano/library trace
 the pdx/vwave/wlan_nano/cafeteria trace
 the pdx/vwave/wlan_nano/pioneer-sq trace
 the pdx/vwave/wlan_nano/urban-grind trace
 the pdx/vwave/wlan_nano/powells trace
 how to cite this traceset