WiSwitcher: an efficient client for managing multiple APs

TitleWiSwitcher: an efficient client for managing multiple APs
Publication TypeConference Paper
Year of Publication2009
AuthorsGiustiniano, D., Goma E., Toledo A. L., & Rodriguez P.
Conference NameProceedings of the 2nd ACM SIGCOMM workshop on Programmable routers for extensible services of tomorrow, PRESTO '09
Date Published08/2009
PublisherACM New York, NY, USA
Conference LocationBarcelona, Spain
ISBN Number978-1-60558-446-1

There has been an increasing interest on designing a single-radio client for time-division access to multiple Access Points (APs) on different radio-channels. These works have focused mainly on different scheduling policies at the client-side to allocate the percentage of time to each AP. However the performance of these systems is limited by 1) the overhead to switch between APs on different radio-channels, 2) the jitter in the switching procedure, that modifies the expected percentage of time assigned by schedulers and 3) the packet losses caused by the switching. In this paper, we introduce WiSwitcher, a client able to connect to multiple APs that i) reduces the cost of switching down to the hardware switching time and ii) increases the stability of the percentage of time assigned by schedulers, even if the station transmits in saturation mode. We implement WiSwitcher over commodity hardware and show that it achieves high aggregate throughput over the connecting APs and seamlessly transmits TCP traffic under controlled scenarios. Finally, we characterize the dependency between the switching frequency at the WiSwitcher client and the packet losses in off-the-shelf APs.