1. Thoughts on AP Functional Descriptions
Feb-19
Thoughts on AP Functional Descriptions
L. Lily Yang
Steve Shellhammer
Intel Corp.
Lily Yang, Steve Shellhammer, Intel

2. Overview Background & Motivation How to achieve interoperability?
Feb-19
Overview
Background & Motivation
How to achieve interoperability?
Scoping for “AP Functional Descriptions”
Requirements and Reality Check
Open Questions for the new SG/TG
Summary & Conclusion
Lily Yang, Steve Shellhammer, Intel

3. AP Functional Descriptions: Logical View
Feb-19
Background
Original “Access Points”:
Logical AP Functions = One Physical Entity (“AP”)
Subsequently in the industry some vendors have partitioned the AP functionality into different physical entities (Example: AP = AC + WTP)
Logical AP Functions = Combination of Physical Entities
AP Functions: Logical
AP Functional Descriptions: Logical View
Lily Yang, Steve Shellhammer, Intel

4. Motivation: Interoperability
Feb-19
Motivation: Interoperability
Interest from IETF: defining a protocol between these physical entities to allow interoperability in the WLAN market
X-Y
Protocol
Physical
Entity X
(Access Controller):
From vendor A
Physical
Entity Y
(Wireless Termination
Point):
From vendor B
interoperable
Lily Yang, Steve Shellhammer, Intel

5. How to achieve interoperability?
Feb-19
How to achieve interoperability?
IETF
interest
X-Y
Protocol
Physical
Entity X
(AC)
Physical
Entity Y
(WTP)
First Step:
Need help from IEEE
Logical Functions for
“AC+WTP”
= “AP Functionality”
It takes efforts from both IEEE and IETF
Lily Yang, Steve Shellhammer, Intel

6. Additional Benefit of “AP Functional Descriptions”
Feb-19
Additional Benefit of “AP Functional Descriptions”
A trend in WG: from “link view” to “wireless network view”
11e, 11n => 11r, 11s
Natural evolution for WLAN architectures
One box AP with BSS-centric view: “Autonomous Architecture”
The need for better coordination to provide inter-BSS services
“Centralized Architecture”: centralized controller for the whole network
“Distributed Architecture”: distributed coordination by peer nodes (example: mesh)
Original AP definitions: interaction with DS is vague
No interoperability within ESS
Need to provide better definitions of ESS and interoperability within ESS
Lily Yang, Steve Shellhammer, Intel

7. Feb-19
Why by IEEE ?
The WG defines the MAC and PHY layers, which are the basis for construction of an AP
The WG embodies the subject matter experts that best understand the workings of an AP and
Lily Yang, Steve Shellhammer, Intel

8. Scoping for “AP Functional Descriptions”
Feb-19
Scoping for “AP Functional Descriptions”
What’s in the scope?
Clear logical decomposition of the AP functionality into some logical units (modules, services, functions, or whatever makes sense)
Clear description of the interaction, relationship or interfaces between these logical units (SAP)
What’s out of the scope?
Physical mapping of these logical units onto physical entities (this implies a specific architecture: belongs to other groups)
Lily Yang, Steve Shellhammer, Intel

9. Basic Requirements for “AP Functional Descriptions”
Feb-19
Basic Requirements for “AP Functional Descriptions”
Better description to
Allow WLAN architecture flexibility and innovation
Facilitate interoperability (possibly with additional work done elsewhere)
Provide common framework for existing and future WLAN architecture development
Lily Yang, Steve Shellhammer, Intel

10. Feb-19
Reality Check
How future proof can it really be? (Common challenge for any technology development)
Architecture flexibility
Support infinite number of arbitrary architectures
Figure out the relevant architectures in today’s market
Study the evolutional path from past and present
Keep eyes on the emerging architectures on the horizon
Interesting architecture examples for study (from IETF CAPWAP WLAN Architecture Taxonomy Document):
Autonomous Architecture
Centralized Architecture (with centralized Access Controller)
Distributed Architecture (peer-to-peer coordination)
Lily Yang, Steve Shellhammer, Intel

11. Need to form a new SG To work on better “AP Functional Definitions”
Feb-19
Need to form a new SG
To work on better “AP Functional Definitions”
Some open questions for SG to investigate
What do we have today in the Standards (as starting points)?
What is missing, lacking, or confusing?
How to approach the functional decomposition (methodology)?
What is the right granularity for decomposition?
How to describe the interface or interaction?
How to better separate data plane and control plane?
What kind of documents will be produced in the end?
What impact does it have on other groups?
Lily Yang, Steve Shellhammer, Intel

12. Reference Model in 802.11 (Clause 5 & 10)
Feb-19
Reference Model in (Clause 5 & 10)
MAC_SAP
MAC
MLME
Station
Management
Entity
(SME)
MLME_SAP
MAC
MIB
PHY_SAP
PLCP
MLME_PLME_SAP
PLME
PMD_SAP
PMD
PHY
MIB
PLME_SAP
Does this represent the whole picture accurately?
Lily Yang, Steve Shellhammer, Intel

13. AP Architecture in IAPP (11F)
Feb-19
AP Architecture in IAPP (11F)
Can we generalize
this beyond IAPP?
Lily Yang, Steve Shellhammer, Intel

14. Data Plane Architecture from 11i
Feb-19
Data Plane Architecture from 11i
Is this a better
approach?
Lily Yang, Steve Shellhammer, Intel

15. Suggested Next Step for IEEE 802.11 WG
Feb-19
Suggested Next Step for IEEE WG
Form a new IEEE SG/TG to provide better AP functional descriptions
Clear logical decomposition of AP functionality
Clear description of the interfaces
Harmonize across different WLAN architectures
Centralized Architectures (with IETF CAPWAP)
Distributed Architecture (with IEEE s)
Lily Yang, Steve Shellhammer, Intel

16. Summary Share our thoughts on AP Functional Descriptions
Feb-19
Summary
Share our thoughts on AP Functional Descriptions
Why? Interoperability.
How? First step is to have common understanding of what constitute “AP functions”.
What? Functional decomposition and interfaces.
Very important first step toward interoperability
Other groups can use this and develop additional protocols to achieve interoperability for a particular architecture
Conclusion: a new study group is needed in WG to accomplish this.
Lily Yang, Steve Shellhammer, Intel