Status Update ofCAPWAP
Architecture TaxonomyLily Yang (Editor)
Intel Corp.
August 4, 200460th IETF meeting
60th IETF: CAPWAP Arch. Taxonomy 2
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)
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