1. The Need for an AP Functional Description
May 2004
doc.: IEEE /540r1
May 2004
The Need for an AP Functional Description
Darwin Engwer, Nortel Networks
Bob O’Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

2. Review and Comment on Taxonomy doc AP Functional Behavior Description
May 2004
doc.: IEEE /540r1
May 2004
Other Groups
Chair’s Special Ad Hoc Committee
Study Group? WG
Review and Comment on Taxonomy doc
AP Functional Behavior Description t
Step 2
Describe the normal features and functions of an AP. Includes identification of core functional modules.
Step 1
Review and comment.
IETF CAPWAP
Taxonomy of Architectures
(CAPWAPA)
CAPWAP
Protocol Specification t
A survey and enumeration of the various architectures present in the world today.
Definition of the in-scope split architectures and protocol spec to support same.
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

3. May 2004
doc.: IEEE /540r1
May 2004
What
To describe the AP architecture and functionality standardized by the current standard and its amendments, or implied by them. The purpose is to provide a better informative description of an AP, to provide:
the basis for interoperability by design (rather than by test),
technical innovation, and
alignment with the work of other groups.
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

4. May 2004
doc.: IEEE /540r1
May 2004
Why
To provide a formal description of the AP for use by other groups.
CAPWAP: There is no direct tie to the CAPWAP effort, other than as a possible input document to CAPWAP for CAPWAP’s potential work on split architectures.
802.1X also needed and needs a clean description of the functions and behaviors of an AP.
TGs (ESS Mesh) will extend the functions of an AP to provide for operation in a mesh of APs. This again requires a clear description of the baseline functions of an AP as a starting point.
will be specifying inter-802 mobility (e.g to , and to 802.3), and also 802 to cellular mobility. These efforts also require a core functional description of an AP.
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

5. May 2004
doc.: IEEE /540r1
May 2004
Intent
The intention of the AP Description SG is to better describe the existing architecture, functionality and requirements of an AP, as it is recorded or implied in adopted standards and amendments.
Split architectures will not be described or standardized.
The work of the eventual AP Description Task Group would be to add informative material, perhaps an informative annex, to to promote better AP designs and improved interoperability.
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

6. AP Description Approach
May 2004
doc.: IEEE /540r1
May 2004
AP Description Approach
functional view vs. component view
functional view describes the functions without regard to any given component or architecture view (i.e. architecture independent)
component view is architecture dependent (e.g. full MAC, split upper/ lower MAC, remote MAC, …)
The AP Descriptions SG should focus on an architecturally independent description (functional view), although both views are required for a complete understanding.
With AP functional descriptions in hand, other groups can perform a component level breakdown to suit their needs.
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

7. May 2004
doc.: IEEE /540r1
May 2004
This diagram, taken from F, shows perhaps the most detailed component level breakdown of an AP to date.
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

8. Distribution Services
May 2004
doc.: IEEE /540r1
May 2004
APME
IAPP
Distribution Services
DS MAC
WM MAC
MLME
DS PHY
WM PHY
PLME
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

9. Distribution Services
May 2004
doc.: IEEE /540r1
May 2004
APME
IAPP
Integration
Distribution Services
Integration
WM MAC
MLME
Portal
WM PHY
DS MAC
PLME
DS PHY
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

10. Distribution Services
May 2004
doc.: IEEE /540r1
May 2004
APME
IAPP
Integration
Distribution Services
Integration
WM MAC
MLME
Portal
WM PHY
DS MAC
PLME
DS PHY
-The base standards (core+a+b+d+g+h…) do a good job of describing (and indeed defining) the WM MAC and WM PHY.
-IAPP is described in F
-Distribution Services are not well described anywhere.
-APME is not well described anywhere.
Distribution System Services:
-Association
-Disassociation
-Distribution
-Integration
MAC Services:
-Beacon generation
-probe response/ transmission
-Control frame processing
-Synchronization
-Retransmission
-Privacy [/ Security]
Station Services:
-Authentication
-Deauthentication
-Privacy [/ Security]
-MSDU Delivery
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

11. May 2004
doc.: IEEE /540r1
May 2004
This diagram, taken from i Draft 9.0, shows a functional breakdown of the MAC data plane. Notice that this is pure functional description, there is no mention of components. A view like this holds perhaps the best hope for an AP description that is architecturally independent of the actual components used to implement that functionality.
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

12. Example Functional Descriptions Needed
May 2004
doc.: IEEE /540r1
May 2004
Example Functional Descriptions Needed
Distribution Services are not described anywhere
Integration is not described anywhere
Portal function is not described anywhere
The association mechanics are described in the standard, possible error codes are identified, but use of those error codes under particular circumstances is not described.
Yet, every AP on the market includes all those functions. QED.
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

13. The End May 2004 doc.: IEEE 802.11-04/540r1 May 2004
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

14. Backup Slides May 2004 doc.: IEEE 802.11-04/540r1 May 2004
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

15. Abstract Systems Analysis
May 2004
doc.: IEEE /540r1
May 2004
Abstract Systems Analysis
"A [system] may be divided for purposes of classical rational analysis by means of its component assemblies and by means of its functions.” - Pirsig
From that it follows ...
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

16. May 2004
doc.: IEEE /540r1
May 2004
AP Systems Analysis
An AP [system] may be divided for purposes of classical rational analysis by means of its component assemblies and by means of its functions.
If divided by means of its component assemblies, its most basic division is into a MAC, a PHY, a distribution system and a management entity.
To know what the components are for, a division according to functions is necessary.
Functionally an AP may be divided [say] into bridging functions, gatekeeper functions and WLAN control functions. Bridging functions may be further subdivided into the authentication service functions, the association service functions, data transport functions and the disassociate service functions.
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

17. The End (Really) May 2004 doc.: IEEE 802.11-04/540r1 May 2004
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace
Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace