Saravanan%20Govindan

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CAPWAP Objectives

• Saravanan Govindan
• March 2005
• ltdraft-ietf-capwap-objectives-00.txtgt

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Background

• WG draft
• Combines objectives from individual submissions
• Includes inputs from IETF 61 discussions
• Structure from CAPWAP charter
• Prioritization of Objectives
• Mandatory Accepted, Desirable, Rejected
• Classification
• Architecture, Operations, Security, Operator
  requirements

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Architecture Objectives (1/2)

• Logical Groups (Mandatory)
• Logical divisions of physical WTP
• Protocol used to manage WLAN in terms of logical
  groups
• Support for Future Wireless Technologies
  (Desirable)
• Protocol messages to be extensible for different
  layer 2 wireless technologies
• Support for New IEEE Extensions (Desirable)
• Accommodate definitions by IEEE groups
• e.g. APF AHC

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Architecture Objectives (2/2)

• Interoperability Objective
• Local-MAC and split-MAC designs to work together
• Protocol involves negotiations to determine
  appropriate split
• Interconnection Objective
• Protocol operations to be independent of
  underlying transport technology
• Multiple Authentication Mechanisms (Desirable)
• IEEE 802.11i support
• Support for other mechanisms e.g. web
  authentication

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Operational Objectives (1/3)

• Support for Traffic Separation (Mandatory)
• User data and control traffic are mutually
  separated
• Simplifies protocol operation
• Device Transparency (Mandatory)
• CAPWAP protocol between AC and WTPs
• Does not affect wireless terminals
• Configuration Consistency (Mandatory)
• Regular exchange of WTP configuration information
• e.g. WTP load, operational state
• Firmware Distribution

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Operational Objectives (2/3)

• System-wide Resource State (Mandatory)
• Exchange of network state information switching
  segment wireless medium segment
• e.g. congestion, interference levels
• Resource Control (Mandatory)
• Protocol to maintain IEEE 802.11e QoS mapping
  across switching and wireless medium segments
• IEEE 802.11i Considerations
• Authenticator and encryption points distinctly
  located
• Key distribution among them (Mandatory)

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Operational Objectives (3/3)

• STA Admission Control
• Access control needs to be based on both
  switching and wireless medium segments
• e.g. control based on congestion and radio
  interference
• Trust Model Definition
• Considerations for separation of authenticator
  and encryption locations
• Security Borderline Control (Desirable)
• Mutual security between logical groups
• Centralized WTP Management (Rejected)
• Protocol to be provisioned for WTPs not managed
  by AC

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Security Objectives

• CAPWAP Protocol Security (Mandatory)
• Mutual authentication
• Secure exchanges between AC and WTPs
• System-wide Security (Mandatory)
• Prevention against outside threats
• e.g. rouge wireless terminals PMK sharing

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Discussions so far (1/3)

• Future Wireless Technologies
• Protocol messages need to be extensible for other
  (non-IEEE 802.11) layer 2 technologies
• CAPWAP Protocol Security
• Key establishment protocol to be secured
  against possible post-establishment compromises
• Transport Layer Independence
• CAPWAP operations to be independent of IP
  versions
• Protocol to operate over intermediate networks
• With possibly many hops
• Possibly under administrations

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Discussions so far (2/3)

• Interoperability Objective
• Managing different split-MAC local-MAC
  variations
• Protocol can provide simple capabilities exchange
• AC can then decide if variations can/will be
  supported
• Traffic Separation
• Control traffic not to be combined with data
  traffic
• Resource Control
• QoS mapping for IEEE 802.11e and other IEEE TG
  semantics (TGk, TGu, TGv)

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Discussions so far (3/3)

• Statistics
• Protocol to allow exchange of various statistics
  information WTP load, loss rates etc.
• Device Transparency
• Protocol to be transparent to wireless devices
  instead of users

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Next Steps

• Discuss objectives further
• Categorization
• Consider any additional objectives
• Finalize requirements and gain consensus

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• Questions?
• Comments?