The Need for an AP Functional Description

1. The Need for anAP Functional Description Darwin Engwer, Nortel Networks Bob O’Hara, Airespace Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

2. Other Groups Chair’s Special Ad Hoc Committee Study Group? Review and Comment on Taxonomy doc 802.11WG 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 andcomment. IETFCAPWAP Taxonomy ofArchitectures (CAPWAPA) CAPWAP ProtocolSpecification 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

3. 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

4. Why • To provide a formal description of the 802.11 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. • 802.11 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. • 802.21 will be specifying inter-802 mobility (e.g. 802.11 to 802.15, and 802.11 to 802.3), and also 802 to cellular mobility. These efforts also require a core functional description of an 802.11 AP. Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

5. 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 802.11 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 802.11 to promote better AP designs and improved interoperability. Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

6. 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

7. Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

8. APME IAPP Distribution Services DS MAC WM MAC MLME DS PHY WM PHY PLME Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

9. 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

10. APME IAPP Integration Distribution Services Integration WM MAC MLME Portal WM PHY DS MAC PLME DS PHY 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

11. Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

12. 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 802.11 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

13. The End Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

14. Backup Slides Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace

15. 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

16. AP Systems Analysis • An 802.11 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

17. The End (Really) Darwin Engwer, Nortel Networks; Bob O'Hara, Airespace