DOI: 10.21227/f698-z174
title: CRAWDAD pdx/vwave

description: date/time of measurement start: 2006-06-12date/time of measurement end: 2006-07-24collection environment: Analysis of the MAC-level behavior of WLANs is required in order to better deploy and design future systems. To this end, collection and analysis of traffic traces is an important task. We collected six traffic traces around Portland, Oregon using a commercial sniffer VWave which has a nano-second time resolution, and conduct an analysis of fine time scale (second or fraction of a second) packet, flow, and error characteristics of these networks.network configuration: We collected data at six different locations of which three (first three below) were located on-campus and three off-campus: - PSU (Portland State University) CS Department Near Faculty Offices in Networking Closet - PSU Library, 3rd Floor - PSU Cafeteria - Office overlooking ``Pioneer Square'' from the second floor - Urban Grind Coffee - Worldcup Coffee at Powell's Booksdata collection methodology: These traces were collected using a VeriWave WT20 Appliance which was kindly loaned to us by the folks at VeriWave http://www.veriwave.com. 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.limitation: We face two challenges in data collection: The first is placement of the VWave sniffer. Because it has a lower effective receiver sensitivity than most access points today (-75dBm versus -90dBm), we must prevent a large possible packet loss with careful antenna choice and placement. The second problem is practical -- we had to obtain permission from the three merchants and further needed to ensure that our equipment was as unobtrusive as possible so as not to affect the ``normal'' behavior of the users.Tracesetpdx/vwave/wlan_nano_fcs/psu-csSupplementary information, including FCS values, for a pcap trace (pdx/vwave/wlan_pcap/psu-cs) collected from PSU (Portland State University) CS Department.file: 2006_06_12_psu_cs.txt.gzconfiguration: Where: PSU (Portland State University) CS Department Near Faculty Offices in Networking Closet Duration: 1 Hour (1500 - 1600), Monday Description: The capture antennas were placed at the same level and immediately in front of the access-point antennas. The closest clients are at least one wall away. We used this site for prototyping our capture methodologies.format: Each trace here contains these fields: starting second (measured from start of capture) starting nanosecond ending second ending nanosecond size (octets) RSSI (calculated) RSSI (raw) FCS error (1 if FCS is bad, 0 otherwise) FCS Fields are separated by non-breaking whitespace, records by newlines. Using timestamps, these traces can be correlated ("merged") with the pcap files. However, note that these files are unfiltered: * They are not filtered by BSSID, they contain everything the radio could hear and decipher. * They contain all frames, including control and management (the pcap files have control frames excluded).pdx/vwave/wlan_nano_fcs/librarySupplementary information, including FCS values, for a Wireless LAN traffic trace (pdx/vwave/wlan_pcap/library) collected from PSU (Portland State University) Library.file: 2006_07_10_library.txt.gzconfiguration: Where: PSU (Portland State University) Library, 3rd Floor Duration: 4 Hours (1400 - 1800), Monday Description: Each library floor is covered by at least three access-points. We positioned our capture antenna on a table, about 4 feet away from the access-point antenna (ceiling mounted) and with roughly the same vantage.format: Each trace here contains these fields: starting second (measured from start of capture) starting nanosecond ending second ending nanosecond size (octets) RSSI (calculated) RSSI (raw) FCS error (1 if FCS is bad, 0 otherwise) FCS Fields are separated by non-breaking whitespace, records by newlines. Using timestamps, these traces can be correlated ("merged") with the pcap files. However, note that these files are unfiltered: * They are not filtered by BSSID, they contain everything the radio could hear and decipher. * They contain all frames, including control and management (the pcap files have control frames excluded).