May 2001 IEEE 802 11 01247 r 0

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May 2001 IEEE 802. 11 -01/247 r 0 P 802. 11 e Network topologies

May 2001 IEEE 802. 11 -01/247 r 0 P 802. 11 e Network topologies and the isochronous cycle coordinator Peter Johansson Congruent Software, Inc. [email protected] org Submission 1 Peter Johansson / Congruent Software, Inc.

May 2001 IEEE 802. 11 -01/247 r 0 Access point vs. coordinator • Historical

May 2001 IEEE 802. 11 -01/247 r 0 Access point vs. coordinator • Historical ambiguity between locations of the infrastructure AP and the coordinator – IEEE Std 802. 11 -1997 (mostly) assumes that the coordination function is co-located with the AP • Wireless stations associate with the AP, not with the coordinator • For some topologies, AP capabilities for coordination may be less than those of another candidate coordinator Submission 2 Peter Johansson / Congruent Software, Inc.

May 2001 IEEE 802. 11 -01/247 r 0 Cycle coordinator • A type of

May 2001 IEEE 802. 11 -01/247 r 0 Cycle coordinator • A type of hybrid coordinator (HC) • Manages isochronous data – Initiates “supercycles” that permit aggregated transmission of isochronous data for multiple 125 ms cycles – Supports management frames that enable stations to allocate and release isochronous bandwidth • See IEEE 802. 11 -01/246 r 0 for more detail – http: //grouper. ieee. org/groups/802/11/index. html Submission 3 Peter Johansson / Congruent Software, Inc.

May 2001 IEEE 802. 11 -01/247 r 0 Home network topologies NIU Cable DSL

May 2001 IEEE 802. 11 -01/247 r 0 Home network topologies NIU Cable DSL Satellite STA AP CC STA STA • AP and cycle coordinator (CC) co-located • Isochronous Qo. S available to all stations Submission 4 Peter Johansson / Congruent Software, Inc.

May 2001 IEEE 802. 11 -01/247 r 0 Home network topologies (cont. ) NIU

May 2001 IEEE 802. 11 -01/247 r 0 Home network topologies (cont. ) NIU Cable DSL Satellite CC AP HC STA STA • AP has only hybrid coordinator capabilities • How is cycle coordinator elected? • How is hybrid cordinator suppressed? Submission 5 Peter Johansson / Congruent Software, Inc.

May 2001 IEEE 802. 11 -01/247 r 0 Home network topologies (cont. ) NIU

May 2001 IEEE 802. 11 -01/247 r 0 Home network topologies (cont. ) NIU Cable DSL Satellite IEEE 1394 Bridge CC STA STA • Apparently an independent services set … • But stations need to associate with the cycle coordinator to obtain isochronous Qo. S Submission 6 Peter Johansson / Congruent Software, Inc.

May 2001 IEEE 802. 11 -01/247 r 0 Coordinator selection within a QBSS •

May 2001 IEEE 802. 11 -01/247 r 0 Coordinator selection within a QBSS • Multiple stations may have the capability to act as a coordinator – Hybrid coordinator (basic functionality) – Cycle coordinator (isochronous support) • Contention algorithm needed – Select most highly qualified station – Amongst equally capable stations, select only one • Don’t fragment into multiple QBSSs Submission 7 Peter Johansson / Congruent Software, Inc.

May 2001 IEEE 802. 11 -01/247 r 0 Contact information Peter Johansson Congruent Software,

May 2001 IEEE 802. 11 -01/247 r 0 Contact information Peter Johansson Congruent Software, Inc. 98 Colorado Avenue Berkeley, CA 94707 (510) 527 -3926 (510) 527 -3856 FAX [email protected] org Submission 8 Peter Johansson / Congruent Software, Inc.