January 2012 doc IEEE 802 11 120112 r

January 2012 doc. : IEEE 802. 11 -12/0112 r 0 Supporting Authentication/Association for Large Number of Stations Authors: Submission Date: 2012 -01 -09 Slide 1 Haiguang Wang et. al, I 2 R, Singapore

January 2012 doc. : IEEE 802. 11 -12/0112 r 0 Abstract In this contribution, we present the performance of current Authentication/Association protocols for 802. 11 networks with large number of nodes. We found that it is necessary to limit the number of stations that can perform the authentication/association simultaneously. Submission Slide 2 Haiguang Wang et. al, I 2 R, Singapore

January 2012 doc. : IEEE 802. 11 -12/0112 r 0 Motivation • IEEE 802. 11 ah is required to support up to 6000 stations by a single AP. It is necessary to examine performance of existing standard in supporting large number of nodes, including authentication/association. Submission Slide 3 Haiguang Wang et. al, I 2 R, Singapore

January 2012 doc. : IEEE 802. 11 -12/0112 r 0 Usage Scenarios • In smart grid application, when AP or stations experience power outage, the stations may try to authenticate/associate with AP simultaneously after recovery. The AP is required to handle a sudden burst of authentication/association requests from a few thousands stations within a short period. Submission Slide 4 Haiguang Wang et. al, I 2 R, Singapore

January 2012 doc. : IEEE 802. 11 -12/0112 r 0 Authentication/Association Procedure Submission Slide 5 Haiguang Wang et. al, I 2 R, Singapore

January 2012 doc. : IEEE 802. 11 -12/0112 r 0 Simulation Parameters • Simulator – Qualnet network simulator • Simulation parameters • • DCF mode • With implemented Authentication/Association protocol. Basic parameters Parameter Value Data Rate 1 Mbps Backoff Win 31 - 1023 Number of Nodes 10 - 3000 Maximum Short Retry 7 DIFS 50 us Maximum long Retry 4 SIFS 10 us Time slot 20 us Submission Slide 6 Haiguang Wang et. al, I 2 R, Singapore

January 2012 doc. : IEEE 802. 11 -12/0112 r 0 Topology 900 800 700 600 500 Stations 400 AP 300 200 100 0 0 Submission 100 200 300 400 500 600 700 800 900 Slide 7 Haiguang Wang et. al, I 2 R, Singapore

doc. : IEEE 802. 11 -12/0112 r 0 Performance Results for Authentication/Association of Stations within 200 Seconds Limit Submission Haiguang Wang et. al, I 2 R, Singapore

January 2012 doc. : IEEE 802. 11 -12/0112 r 0 Suggested Solution • Limit the number of stations that can authenticate/associate with AP at the same time. – Make use of the last byte of station’s MAC address to limit the number of stations. – AP broadcast a value V in the beacon. – Stations with last byte of MAC address less than V are allowed to send authentication request. – AP can adjust the value of V to control the number of stations performing authentication/association process. Submission Slide 9 Haiguang Wang et. al, I 2 R, Singapore

January 2012 doc. : IEEE 802. 11 -12/0112 r 0 Performance Results by Limiting Number of Stations Submission Slide 10 Haiguang Wang et. al, I 2 R, Singapore

January 2012 doc. : IEEE 802. 11 -12/0112 r 0 Conclusions • Simulation results show that, it is necessary to control the number of stations performing authentication/association at the same time to improve the performance in scenario with large number of stations. Submission Slide 11 Haiguang Wang et. al, I 2 R, Singapore

January 2012 doc. : IEEE 802. 11 -12/0112 r 0 References • [1] Chao-Chun Wang, “Supporting Large Number of STAs in 802. 11 ah”, IEEE 802. 11 -11/1019, July 2011 Submission Slide 12 Haiguang Wang et. al, I 2 R, Singapore

January 2012 doc. : IEEE 802. 11 -12/0112 r 0 Straw Poll (1) • Do you agree that AP should limit the number of stations to be authenticated/associated at the same time? • Y: • N: • A: Submission Slide 13 Haiguang Wang et. al, I 2 R, Singapore

January 2012 doc. : IEEE 802. 11 -12/0112 r 0 Straw Poll (2) • Do you agree to use MAC address to limit the number of stations to be authenticated/associated at the same time? • Y: • N: • A: Submission Slide 14 Haiguang Wang et. al, I 2 R, Singapore