May 2002

Lily Yang, Tyan-Shu Jou

Slide 1

doc.: IEEE 802.11-04/595r2

Submission

Mesh Relevance in CAPWAP and

AP Functional Descriptions

L. Lily Yang (Intel Corp.)Tyan-Shu Jou (Janusys Networks)

lily.l.yang@intel.comtsjou@janusysnetworks.com

May 2002

Lily Yang, Tyan-Shu Jou

Slide 2

doc.: IEEE 802.11-04/595r2

Submission

Overview

• Intro to IETF CAPWAP– The role of mesh in CAPWAP – Need help from mesh vendors

• The need for “AP Functional Descriptions”– Why?– Benefits (to mesh group and others)– Need a new SG

• References

May 2002

Lily Yang, Tyan-Shu Jou

Slide 3

doc.: IEEE 802.11-04/595r2

Submission

IETF CAPWAP Problem Statement

• Network administration burden:– Management– Monitoring– Control

• Effective RF dynamic provisioning: needs coordination among APs

• Maintaining Consistent Configuration• Security:

– Access to the network (e.g., physical security of APs)– Rogue AP detection

May 2002

Lily Yang, Tyan-Shu Jou

Slide 4

doc.: IEEE 802.11-04/595r2

Submission

CAPWAP Architecture Taxonomy

AutonomousArchitecture

CentralizedArchitecture

DistributedArchitecture

802.11 WLAN

Architectures

* Centralized controller

* Distributed control across multiple nodes

* Self-contained controller

Categorized by Control Plane Characteristics

May 2002

Lily Yang, Tyan-Shu Jou

Slide 5

doc.: IEEE 802.11-04/595r2

Submission

From Autonomous to Centralized

Local MAC

Split MAC

Remote MAC

AP Functionality

WTP AC

Real Time MACPHY Non RT MAC Control & Config

Autonomous

WTP

MACPHY Control & Config

ACWTP

MACPHY Control & Config

WTP AC

Real Time MACPHY Non RT MAC Control & Config

May 2002

Lily Yang, Tyan-Shu Jou

Slide 6

doc.: IEEE 802.11-04/595r2

Submission

What about Mesh?• Data plane: de-centralized, multi-hop• Control plane: can be either [2]

– Centralized, or– Distributed, or– Hybrid

• CAPWAP may offer a solution for control and management in mesh networks

STA 1 STA2

AP #1

STA 3 STA 4

AP #3

External Network

AP #2

STA 5

AC Portal

May 2002

Lily Yang, Tyan-Shu Jou

Slide 7

doc.: IEEE 802.11-04/595r2

Submission

Help needed from mesh vendors• CAPWAP mailing list:

http://www.ietf.org/html.charters/capwap-charter.html

• Current taxonomy document:– http://www.ietf.org/internet-drafts/draft-ietf-capwap-

arch-02.txt– Need help from mesh vendors on distributed control– Timeline:

• next 2-3 weeks for another revision• Possibly WG last call by end of June

• Encourage everyone to participate

May 2002

Lily Yang, Tyan-Shu Jou

Slide 8

doc.: IEEE 802.11-04/595r2

Submission

“AP Functional Descriptions”: What? [5]

• 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.

May 2002

Lily Yang, Tyan-Shu Jou

Slide 9

doc.: IEEE 802.11-04/595r2

Submission

Trends (Why?) [5]

• A trend in 802.11 WG:– from “link view” to “wireless network view”– i.e. from 11e, 11n ==> 11r, 11s, WNM, WIEN

• Natural evolution for WLAN architectures– From one-box AP with BSS-centric view (“Autonomous

Architecture”)– To better coordinated inter-BSS services:

• “Distributed Architecture”: distributed coordination by peer nodes (example: mesh)

• “Centralized Architecture”: centralized controller for the network

• Original AP definitions: interaction with the DS is vague– No interoperability within ESS

• Need to provide better descriptions of ESS and interoperability within the ESS

May 2002

Lily Yang, Tyan-Shu Jou

Slide 10

doc.: IEEE 802.11-04/595r2

Submission

What Groups can Benefit from This?[5]

• To provide a formal description of the 802.11 AP for use by other groups.– 802.1X also needed and needs a clean description of the functions

and behaviors of an AP.

– CAPWAP: The AP functional descriptions can be used by the IETF CAPWAP group.

– 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.

May 2002

Lily Yang, Tyan-Shu Jou

Slide 11

doc.: IEEE 802.11-04/595r2

Submission

Need to form a new SG [5]

• To work on better “AP Functional Descriptions”• 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,

granularity)?– 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 802.11 groups?

• Current discussions in ESS Mesh touch some of these questions, but mostly around mesh and for mesh. => A new SG is needed to address these general issues.

May 2002

Lily Yang, Tyan-Shu Jou

Slide 12

doc.: IEEE 802.11-04/595r2

Submission

IAPP

Distribution Services

DS MAC

DS PHY

Portal Integration

WM MAC

WM PHY

APME

MLME

PLME

One Possible Starting Point based on IAPP Diagram [4]

Mesh Relevance: First need to figure out the baseline AP functions,

and then figure out where/what ESS mesh functions are …

May 2002

Lily Yang, Tyan-Shu Jou

Slide 13

doc.: IEEE 802.11-04/595r2

Submission

ESS Mesh Group can also help AP Functional Descriptions

• A lot of the questions about AP, DS, DSS, ESS are being asked here by ESS mesh groupIndication of the need to re-examine the current

descriptionsBetter understanding can result from the

discussion hereCan potentially feedback to the new SG/TG

May 2002

Lily Yang, Tyan-Shu Jou

Slide 14

doc.: IEEE 802.11-04/595r2

Submission

Summary

• Encourage mesh vendors here to participate in IETF CAPWAP and contribute to the discussion of Distributed Architecture

• Encourage ESS Mesh Group to stay informed of the CFI on AP Functional Descriptions in WNG and contribute to the effort

May 2002

Lily Yang, Tyan-Shu Jou

Slide 15

doc.: IEEE 802.11-04/595r2

Submission

References

• For additional information, please refer to these more detailed submissions:– [1] 11-04-0544-00-0wng-ap-functional-needs-capwap.ppt

– [2] 11-04-0527-00-0wng-wlan-mesh-in-capwap-architecture.ppt

– [3] 11-04-0481-03-0wng-thoughts-on-ap-functional-descriptions.ppt

– [4] 11-04-0540-00-0wng-need-ap-functional-descriptions.ppt

– [5] 11-04-0604-00-0wng-ap-functional-descriptions-update.ppt