Improved Access Point Selection
Abstract
This paper presents Virgil, an automatic access point discov-
ery and selection system. Unlike existing systems that se-
lect access points based entirely on received signal strength,
Virgil scans for all available APs at a location, quickly as-
sociates to each, and runs a battery of tests to estimate the
quality of each AP’s connection to the Internet. Virgil also
probes for blocked or redirected ports, to guide AP selection
in favor of preserving application services that are currently
in use. Results of our evaluation across five neighborhoods in
three cities show Virgil finds a usable connection from 22%
to 100% more often than selecting based on signal strength
alone. By caching AP test results, Virgil both improves per-
formance and success rate. Our overhead is acceptable and
is shown to be faster than manually selecting an AP with
Windows XP.