Achievable Performance of Beacon-based Service Publishing in Multi-service Wi-Fi Hot-spots

In an expected future multi-access and multi-service IEEE 802.11 environment, the problem of providing users with useful service-related information to support a correct, rapid network selection is expected to become a very important issue. A feasible, short-term 802.11-tailored working solution, compliant with existing equipment, is to publish service information encoded within the SSID Information Element within beacon frames. This makes it possible for an operator to implement service publishing in 802.11 networks while waiting for a standardized mechanism. Also, this straightforward approach has allowed us to evaluate experimentally the performance of a beacon-based service publishing solution. In fact, the main focus of the paper is indeed to present a quantitative comparison of service discovery times between the legacy scenario, where the user is forced to associate and authenticate with a network point of access to check its service offer, and the enhanced scenario where the set of servicerelated information is broadcasted within beacons. These discovery times are obtained by processing the results of a measurement campaign performed in a multi-access/service 802.11 environment. This analysis confirms the effectiveness of the beacon-based approach. We also show that the cost in terms of wireless bandwidth consumption of such a solution is low. Keywords— IEEE 802.11, service information broadcasting, network selection, prototype implementation, benefit and cost evaluation A preliminary, shorter version of this paper has been published in the Proceedings of ASWN 2006, Berlin, Germany, May 2006: D. Di Sorte, M. Femminella, G. Reali, “Service publishing to support an efficient 802.11 network selection,” Proceedings of 6th International Workshop on Applications and Services in Wireless Networks (ASWN), Berlin, Germany, May 2006. Corresponding author: Dr. Dario Di Sorte DIEI – University of Perugia Via G. Duranti 93 I-06125 Perugia, Italy [email protected] Tel: +39 075 5853630, Fax: +39 075 5853654