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only 23.61% were not. A similar result is observed during the night scan as shown in
Table 4.9.
4.2.4.3 Default SSID
Encryption Day Scan Night Scan
Total % Total %
On 306 73.73 220 75.60
Off 98 23.61 69 23.71
Total SSID 404 289
Table 4.9 Broadcasted SSID detected and encryption status
Three usage of the default SSID were reported by Netstumbler during the day scan
while only one was reported for the night scan. It was reported in 2004 that 13.1% of
the WLAN detected are still using the default SSID value (Jeffcoate, Chappell, & Feindt,
2002). This show a sharp decrease in default SSID usage from 2004 to 2007.
4.2.5 Combined Day and Night data
The purpose of merging both day scan and night scan data is to evaluate the actual
WLAN detected on 26 June 2007 and to confirm the analysis on both the day and night
data previously. The merged data will be evaluated based on the actual number of
WLAN detected during the day, the encryption status, operation mode, and SSID.
4.2.5.1 Total WLAN Detected
The actual WLAN distribution during the field trials can be determined by filtering the
MAC address based on the time of its “first seen” and “last seen” fields in the report
produced by the Netstumbler program. The total number of actual WLAN detected was
506, with 225 WLAN appearing on both scans, 204 appearing only in the day scan, and
78 appearing only in the night scan. Table 4.10 represents the data discussed earlier.
The list of MAC addresses can be viewed in Appendix 2. This showed that the WLANs
detected in Auckland CBD have increased 114%.
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