1. P802.11e Network topologies and the isochronous cycle coordinator
Month 2000
doc.: IEEE /xxx
May 2001
P802.11e Network topologies and the isochronous cycle coordinator
Peter Johansson Congruent Software, Inc.
Peter Johansson / Congruent Software, Inc.
John Doe, His Company

2. Access point vs. coordinator
May 2001
Access point vs. coordinator
Historical ambiguity between locations of the infrastructure AP and the coordinator
IEEE Std (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
Peter Johansson / Congruent Software, Inc.

3. Cycle coordinator A type of hybrid coordinator (HC)
May 2001
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 /246r0 for more detail
Peter Johansson / Congruent Software, Inc.

4. Home network topologies
May 2001
Home network topologies
Cable DSL Satellite
NIU
STA
AP CC
STA
STA
STA
AP and cycle coordinator (CC) co-located
Isochronous QoS available to all stations
Peter Johansson / Congruent Software, Inc.

5. Home network topologies (cont.)
May 2001
Home network topologies (cont.)
Cable DSL Satellite
NIU CC
AP HC
STA
STA
STA
AP has only hybrid coordinator capabilities
How is cycle coordinator elected?
How is hybrid cordinator suppressed?
Peter Johansson / Congruent Software, Inc.

6. Home network topologies (cont.)
May 2001
Home network topologies (cont.)
IEEE 1394
STA
Cable DSL Satellite
Bridge CC
NIU
Apparently an independent services set …
But stations need to associate with the cycle coordinator to obtain isochronous QoS
Peter Johansson / Congruent Software, Inc.

7. Coordinator selection within a QBSS
May 2001
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
Peter Johansson / Congruent Software, Inc.

8. May 2001
Contact information
Peter Johansson
Congruent Software, Inc. 98 Colorado Avenue Berkeley, CA
(510) (510) FAX
Peter Johansson / Congruent Software, Inc.