Status Update ofCAPWAP

Architecture TaxonomyLily Yang (Editor)

Intel Corp.

August 4, 200460th IETF meeting

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Overview

• What happened since last IETF?

• Learning from the taxonomy work (v04)

• Conclusions

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Draft History Since 59th IETF• March:

– V00: minor revision from the individual draft– 59th IETF at Seoul: Design Team (12 people)– Architecture Survey (14 submissions)– Presented to IEEE 802.11, started discussion on AP Functional Description

• April: major rewrite of the draft– v01: basic outline of the architecture landscapes, adopting Matrix for data representation– V02: refinement of text and draft organization

• May: – IEEE 802.11 review (50+ comments)– IETF CAPWAP WG mailing list comments– IEEE 802.11 WG approved formation of new SG for AP Functional Description

• June: – 2 more survey submissions (mesh vendors)– V03: incorporated IEEE+IETF comments and rewrote section on distributed arch.

• July: – More comments and discussion at the mailing list– V04: incorporated above comments)

• Aug: – Received comments from security review– Plan to do v05 next week: incorporate comments from above– Ready for WG last call => Informational RFC

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Design Team• Lily Yang (Intel, Editor) • Petros Zerfos (UCLA)• Sadot, Emek (Avaya) • Ajit Sanzgiri (Cisco Systems) • Bob O’Hara (AireSpace)• Dave Hetherington (Roving Planet)• Inderpreet Singh (Chantry Networks)• Jim Murphy (Trapeze Networks)• Matt Holdrege (Strix Systems)• Partha Narasimhan (Aruba Wireless Networks)• Peyush AGARWAL (STMicroelectronics)• Victor Lin (Extreme Networks)

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Architecture Survey Template

• Design considerations & requirements• WLAN functions supported• The functional architecture to implement the

functions described• The protocol used between network entities• Network connectivity assumptions (L2 or L3)• Security Analysis• Pros and Cons

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16 Architecture Survey Submissions

• AireSpace

• Aruba Wireless Networks

• Avaya

• Chantry Networks

• Cisco Sytems

• Cranite Systems

• Extreme Networks,

• Instant802

• Intoto

• Janusys Networks

• Nortel Networks

• Panasonic

• Strix Systems

• Symbol

• Trapeze

• UCLA

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CAPWAP Architecture Taxonomy

AutonomousArchitecture

CentralizedArchitecture

DistributedArchitecture

802.11 WLAN

Architectures

* Centralized controller

* Distributed control across multiple nodes

* Self-contained controller

Categorized Largely by Control Plane Characteristics

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Autonomous Architecture: Traditional WLAN Architecture

STA 1 STA2

AP

STA 3 STA 4

AP

• Autonomous (standalone) AP: “fat” and self-contained AP

• No explicit infrastructure support for “wireless”

• Each AP provides most of the WLAN functions including “distribution”, “integration” and other L3 services within itself.

External Network

AP

STA 5

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Centralized Architecture

STA 1STA2

WTP

STA 3 STA 4

WTP

External Network

WTP

Access Controller (AC)

STA 5

• “WTP + AC” together implements AP functions• Advantages of AC:

– centralized controller(s) => manageability for large networks

– network wide visibility => better coordination across the network

• Challenges: – no standard way of splitting AP functions onto WTP and

ACCurrent State of Art: No interoperability

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From Autonomous to Centralized

Local MAC(5)

Split MAC(6)

Remote MAC(1)

AP Functionality

WTP AC

Real Time MACPHY Non RT MAC Control & Config

Autonomous (1) WTP

MACPHY Control & Config

ACWTP

MACPHY Control & Config

WTP AC

Real Time MACPHY Non RT MAC Control & Config

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Functional Distribution Matrix for Local MAC

Arch7 Arch8 Arch9 Arch10 Arch11 ----- ----- ----- ------ ------ connectivity L3 L3 L3 L3 L3

802.11 mgmt termination WTP WTP WTP WTP WTP

802.11 control termination WTP WTP WTP WTP WTP

802.11 data aggregation AC AC WTP AC WTP

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Functional Distribution Matrix for Split MAC

Arch1 Arch2 Arch3 Arch4 Arch5 Arch6 ----- ----- ----- ------ ------ ------ connectivity L3 L3 L3 L2 L3 L3

802.11 mgmt

termination AC AC AC AC AC/WTP AC

802.11 control termination WTP WTP WTP WTP WTP WTP

802.11 data aggregation AC AC AC AC AC AC

Same as Local MAC

Different than Local

MAC

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From Centralized to Distributed: Mesh Example

• Data plane: de-centralized, multi-hop

• Control plane: can be either – Centralized, or– Distributed (via peer-to-peer mesh interface), or– Hybrid

STA 1 STA2

WTP #1

STA 3 STA 4

WTP #3

External Network

WTP #2

STA 5

AC Portal

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Summary• 3 distinct architecture families:

– Autonomous (traditional)– Centralized (current generation)– Distributed (emerging, 802.11 TGs)

• Among the centralized architecture family: 3 sub-categories– Remote MAC: severe constraints on AC-WTP inter-connection & WTP capability– Local MAC: there exists enough commonality that should make cross-vendor

interoperability feasible.– Split MAC: cross-vendor interoperability should also be feasible.

• Harder question: Interoperability across architectures (e.g. between local MAC & Split MAC)?

– Is it necessary?– Is it feasible?

• Next Steps:– Define the exact interoperability scope for the protocol(s)

• Target architecture(s)• If multiple architectures: Same or different protocols?

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Proposed Next Steps

V05: WG Last call

Aug IESG review for Informational RFC publication

Re-charter for Protocol work: define the scope for

interoperability

(architecture assumptions,Protocol requirements, …)

Sept

ProtocolProposal(s)

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Design Team Mission Accomplished (almost)

THANK YOU• Lily Yang (Intel, Editor) • Petros Zerfos (UCLA)• Sadot, Emek (Avaya) • Ajit Sanzgiri (Cisco Systems) • Bob O’Hara (AireSpace)• Dave Hetherington (Roving Planet)• Inderpreet Singh (Chantry Networks)• Jim Murphy (Trapeze Networks)• Matt Holdrege (Strix Systems)• Partha Narasimhan (Aruba Wireless Networks)• Peyush AGARWAL (STMicroelectronics)• Victor Lin (Extreme Networks)