1. Status of CAPWAP Architecture Draft Lily Yang Intel Corp. March 3, 2004 59 th IETF meeting

2. IETF 59th CAPWAP Architecture2 Overview What happened since last IETF? What should this draft cover? Where are we today? –Basic thinking –Comments received What is the plan going forward?

3. IETF 59th CAPWAP Architecture3 draft-ietf-capwap-arch-00 Co-Authors: –Bob O’Hara (AireSpace) –Lily Yang (Intel) Not much change from draft-mani-capwap-arch-00 New developments since 58 th IETF: –WG officially approved –New Charter => new focus on Problem Statement Architecture (taxonomy) –Architecture draft: WG work item –Timeline: 6 month (by Aug.) –Design Team Expectation: Need significant rework on the draft

4. IETF 59th CAPWAP Architecture4 What should the architecture draft cover? Architecture taxonomy: different ways to implement WLAN functions –Standalone AP architecture –“AP + AC” architecture & its variants in the market Pros and Cons for each Security threats for each Functional interfaces for each Interoperability vs flexibility challenge –Is it feasible to support all variants? –If not, then what?

5. IETF 59th CAPWAP Architecture5 WLAN Architecture Defined by 802.11 today Services defined by.11: –Station Services: Auth./De-auth. Privacy MSDU delivery –Distribution System Services: Asso., Disasso., Reasso. Distribution Integration (via “portal”) Other functions: –Mobility support –AP Load balancing –Dynamic RF mgmt & control –Better network security –… Distribution System (DS) STA3STA4 AP STA5 STA6 AP Portal STA1STA2 AP External Network Implementation of DS is NOT part of the 802.11 standard.

6. IETF 59th CAPWAP Architecture6 802.11 WLAN Architecture I: Autonomous AP STA 1STA2 AP STA 3STA 4 AP External Network Autonomous (standalone) AP: “fat” and self- contained AP No explicit infrastructure support Each AP provides most of the WLAN functions within itself.

7. IETF 59th CAPWAP Architecture7 802.11 WLAN Architecture II: AP + AC (Access Controller) STA 1STA2 AP STA 3STA 4 AP External Network AP Access Controller (AC) “AP + AC” together implements WLAN 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 => no interoperability Key Issue: How the WLAN functions are “split” among AP and AC?

8. IETF 59th CAPWAP Architecture8 “Split” Spectrum: Architecture & Topology x Fat AP (ARCH0) Antenna AP (ARCH3): AP=Antenna AC = MAC & above x Split AP (ARCH1): AP= MAC AC= above x Split MAC (ARCH2): AP=RT MAC AC = NRT & above x direct L3 L2 topology Split architecture x x x x x x x x x

9. IETF 59th CAPWAP Architecture9 Comments received so far How to categorize the architecture variants: –Not enough info –Need more analysis on pros/cons Confusing “architectures” with “topologies” Should move away from some assumptions made by LWAPP Need lots of work!

10. IETF 59th CAPWAP Architecture10 The Plan Going Forward Functional split of AP and AC Network topological considerations Security threats Pros and cons Architecture variants WG Architecture Taxonomy DT Expert review IEEE Data analysis Categorization Tradeoff of Interoperability vs. flexibility Recommendations 03/17v01: ? AP functional Definition IETF Protocol(s) IESG review ? ? Aug 04 ?

11. IETF 59th CAPWAP Architecture11 First Call to Action Each vendor/participant to submit –WLAN functions supported –How the functions map to AP and AC? –What are the topological assumptions between AP and AC? –Security analysis on threats –Pros and Cons of the architecture variant By March 17 !

12. IETF 59th CAPWAP Architecture12 Summary We expect to revise the draft significantly. One step at a time: –Taxonomy –Analysis –Recommendations to IEEE Lets do it!