Rssi

RSSI is a unit wich measures a link quality:

short: the lower the rssi-value,the better the linkquality. (rssi-50 is much better then rssi-80)

http://www.stud.tu-ilmenau.de/~babi-mtr/wirelessweimar/wifiwe-RSSI_to_dBm.gif

example: [ http://noc.auth.gr/stats/network/bld27wless/bld27a-rssi.html ]
further info: [ http://www.winlab.rutgers.edu/~harisk/RSSI.pdf ]