draft-ietf-capwap-protocol-specification-06.txt   draft-ietf-capwap-protocol-specification-07.txt 
Network Working Group P. Calhoun, Editor Network Working Group P. Calhoun, Editor
Internet-Draft Cisco Systems, Inc. Internet-Draft Cisco Systems, Inc.
Expires: September 11, 2007 M. Montemurro, Editor Expires: December 13, 2007 M. Montemurro, Editor
Research In Motion Research In Motion
D. Stanley, Editor D. Stanley, Editor
Aruba Networks Aruba Networks
June 11, 2007
CAPWAP Protocol Specification CAPWAP Protocol Specification
draft-ietf-capwap-protocol-specification-06 draft-ietf-capwap-protocol-specification-07
Status of this Memo Status of this Memo
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skipping to change at page 1, line 35 skipping to change at page 1, line 37
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Copyright Notice Copyright Notice
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2007).
Abstract Abstract
This specification defines the Control And Provisioning of Wireless This specification defines the Control And Provisioning of Wireless
Access Points (CAPWAP) Protocol. The CAPWAP protocol meets the IETF Access Points (CAPWAP) Protocol. The CAPWAP protocol meets the IETF
CAPWAP working group protocol requirements. The CAPWAP protocol is CAPWAP working group protocol requirements. The CAPWAP protocol is
designed to be flexible, allowing it to be used for a variety of designed to be flexible, allowing it to be used for a variety of
wireless technologies. This document describes the base CAPWAP wireless technologies. This document describes the base CAPWAP
protocol. The CAPWAP protocol binding which defines extensions for protocol. The CAPWAP protocol binding which defines extensions for
use with the IEEE 802.11 wireless LAN protocol is available in [14]. use with the IEEE 802.11 wireless LAN protocol is available in [12].
Extensions are expected to be defined to enable use of the CAPWAP Extensions are expected to be defined to enable use of the CAPWAP
protocol with additional wireless technologies. protocol with additional wireless technologies.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 7
1.1. Goals . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.2. Conventions used in this document . . . . . . . . . . . . 8
1.3. Contributing Authors . . . . . . . . . . . . . . . . . . 9
1.4. Terminology . . . . . . . . . . . . . . . . . . . . . . . 10
2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 11
2.1. Wireless Binding Definition . . . . . . . . . . . . . . . 12
2.2. CAPWAP Session Establishment Overview . . . . . . . . . . 13
2.3. CAPWAP State Machine Definition . . . . . . . . . . . . . 14
2.3.1. CAPWAP Protocol State Transitions . . . . . . . . . . 16
2.3.2. CAPWAP/DTLS Interface . . . . . . . . . . . . . . . . 27
2.4. Use of DTLS in the CAPWAP Protocol . . . . . . . . . . . 29
2.4.1. DTLS Handshake Processing . . . . . . . . . . . . . . 29
2.4.2. DTLS Session Establishment . . . . . . . . . . . . . 30
2.4.3. DTLS Error Handling . . . . . . . . . . . . . . . . . 31
2.4.4. DTLS EndPoint Authentication and Authorization . . . 32
3. CAPWAP Transport . . . . . . . . . . . . . . . . . . . . . . 36
3.1. UDP Transport . . . . . . . . . . . . . . . . . . . . . . 36
3.2. UDP-Lite Transport . . . . . . . . . . . . . . . . . . . 36
3.3. AC Discovery . . . . . . . . . . . . . . . . . . . . . . 36
3.4. Fragmentation/Reassembly . . . . . . . . . . . . . . . . 38
4. CAPWAP Packet Formats . . . . . . . . . . . . . . . . . . . . 39
4.1. CAPWAP Preamble . . . . . . . . . . . . . . . . . . . . . 41
4.2. CAPWAP Header . . . . . . . . . . . . . . . . . . . . . . 41
4.3. CAPWAP Data Messages . . . . . . . . . . . . . . . . . . 45
4.3.1. CAPWAP Data Keepalive . . . . . . . . . . . . . . . . 45
4.3.2. Data Payload . . . . . . . . . . . . . . . . . . . . 46
4.3.3. Establishment of a DTLS Data Channel . . . . . . . . 47
4.4. CAPWAP Control Messages . . . . . . . . . . . . . . . . . 47
4.4.1. Control Message Format . . . . . . . . . . . . . . . 48
4.4.2. Control Message Quality of Service . . . . . . . . . 51
4.4.3. Retransmissions . . . . . . . . . . . . . . . . . . . 51
4.5. CAPWAP Protocol Message Elements . . . . . . . . . . . . 52
4.5.1. AC Descriptor . . . . . . . . . . . . . . . . . . . . 54
4.5.2. AC IPv4 List . . . . . . . . . . . . . . . . . . . . 56
4.5.3. AC IPv6 List . . . . . . . . . . . . . . . . . . . . 57
4.5.4. AC Name . . . . . . . . . . . . . . . . . . . . . . . 57
4.5.5. AC Name with Index . . . . . . . . . . . . . . . . . 58
4.5.6. AC Timestamp . . . . . . . . . . . . . . . . . . . . 58
4.5.7. Add MAC ACL Entry . . . . . . . . . . . . . . . . . . 59
4.5.8. Add Station . . . . . . . . . . . . . . . . . . . . . 59
4.5.9. Add Static MAC ACL Entry . . . . . . . . . . . . . . 60
4.5.10. CAPWAP Control IPv4 Address . . . . . . . . . . . . . 61
4.5.11. CAPWAP Control IPv6 Address . . . . . . . . . . . . . 61
4.5.12. CAPWAP Timers . . . . . . . . . . . . . . . . . . . . 62
4.5.13. Data Transfer Data . . . . . . . . . . . . . . . . . 63
4.5.14. Data Transfer Mode . . . . . . . . . . . . . . . . . 63
4.5.15. Decryption Error Report . . . . . . . . . . . . . . . 64
4.5.16. Decryption Error Report Period . . . . . . . . . . . 64
4.5.17. Delete MAC ACL Entry . . . . . . . . . . . . . . . . 65
4.5.18. Delete Station . . . . . . . . . . . . . . . . . . . 66
4.5.19. Delete Static MAC ACL Entry . . . . . . . . . . . . . 66
4.5.20. Discovery Type . . . . . . . . . . . . . . . . . . . 67
4.5.21. Duplicate IPv4 Address . . . . . . . . . . . . . . . 68
4.5.22. Duplicate IPv6 Address . . . . . . . . . . . . . . . 69
4.5.23. Idle Timeout . . . . . . . . . . . . . . . . . . . . 70
4.5.24. Image Data . . . . . . . . . . . . . . . . . . . . . 70
4.5.25. Image Identifier . . . . . . . . . . . . . . . . . . 71
4.5.26. Image Information . . . . . . . . . . . . . . . . . . 71
4.5.27. Initiate Download . . . . . . . . . . . . . . . . . . 72
4.5.28. Location Data . . . . . . . . . . . . . . . . . . . . 72
4.5.29. Maximum Message Length . . . . . . . . . . . . . . . 73
4.5.30. MTU Discovery Padding . . . . . . . . . . . . . . . . 73
4.5.31. Radio Administrative State . . . . . . . . . . . . . 74
4.5.32. Radio Operational State . . . . . . . . . . . . . . . 74
4.5.33. Result Code . . . . . . . . . . . . . . . . . . . . . 75
4.5.34. Returned Message Element . . . . . . . . . . . . . . 77
4.5.35. Session ID . . . . . . . . . . . . . . . . . . . . . 77
4.5.36. Statistics Timer . . . . . . . . . . . . . . . . . . 78
4.5.37. Vendor Specific Payload . . . . . . . . . . . . . . . 78
4.5.38. WTP Board Data . . . . . . . . . . . . . . . . . . . 79
4.5.39. WTP Descriptor . . . . . . . . . . . . . . . . . . . 80
4.5.40. WTP Fallback . . . . . . . . . . . . . . . . . . . . 81
4.5.41. WTP Frame Tunnel Mode . . . . . . . . . . . . . . . . 82
4.5.42. WTP IPv4 IP Address . . . . . . . . . . . . . . . . . 83
4.5.43. WTP MAC Type . . . . . . . . . . . . . . . . . . . . 83
4.5.44. WTP Name . . . . . . . . . . . . . . . . . . . . . . 84
4.5.45. WTP Operational Statistics . . . . . . . . . . . . . 84
4.5.46. WTP Radio Statistics . . . . . . . . . . . . . . . . 85
4.5.47. WTP Reboot Statistics . . . . . . . . . . . . . . . . 86
4.5.48. WTP Static IP Address Information . . . . . . . . . . 88
4.6. CAPWAP Protocol Timers . . . . . . . . . . . . . . . . . 89
4.6.1. ChangeStatePendingTimer . . . . . . . . . . . . . . . 89
4.6.2. DataChannelDeadInterval . . . . . . . . . . . . . . . 89
4.6.3. DiscoveryInterval . . . . . . . . . . . . . . . . . . 89
4.6.4. DTLSSessionDelete . . . . . . . . . . . . . . . . . . 89
4.6.5. EchoInterval . . . . . . . . . . . . . . . . . . . . 89
4.6.6. KeyLifetime . . . . . . . . . . . . . . . . . . . . . 90
4.6.7. MaxDiscoveryInterval . . . . . . . . . . . . . . . . 90
4.6.8. MaxFailedDTLSSessionRetry . . . . . . . . . . . . . . 90
4.6.9. NeighborDeadInterval . . . . . . . . . . . . . . . . 90
4.6.10. ResponseTimeout . . . . . . . . . . . . . . . . . . . 90
4.6.11. RetransmitInterval . . . . . . . . . . . . . . . . . 90
4.6.12. SilentInterval . . . . . . . . . . . . . . . . . . . 91
4.6.13. StatisticsTimer . . . . . . . . . . . . . . . . . . . 91
4.6.14. WaitDTLS . . . . . . . . . . . . . . . . . . . . . . 91
4.6.15. WaitJoin . . . . . . . . . . . . . . . . . . . . . . 91
4.7. CAPWAP Protocol Variables . . . . . . . . . . . . . . . . 91
4.7.1. AdminState . . . . . . . . . . . . . . . . . . . . . 91
4.7.2. DiscoveryCount . . . . . . . . . . . . . . . . . . . 91
4.7.3. FailedDTLSAuthFailCount . . . . . . . . . . . . . . . 92
4.7.4. FailedDTLSSessionCount . . . . . . . . . . . . . . . 92
4.7.5. IdleTimeout . . . . . . . . . . . . . . . . . . . . . 92
4.7.6. MaxDiscoveries . . . . . . . . . . . . . . . . . . . 92
4.7.7. MaxRetransmit . . . . . . . . . . . . . . . . . . . . 92
4.7.8. ReportInterval . . . . . . . . . . . . . . . . . . . 92
4.7.9. RetransmitCount . . . . . . . . . . . . . . . . . . . 92
4.7.10. WTPFallBack . . . . . . . . . . . . . . . . . . . . . 92
4.8. WTP Saved Variables . . . . . . . . . . . . . . . . . . . 92
4.8.1. AdminRebootCount . . . . . . . . . . . . . . . . . . 93
4.8.2. FrameEncapType . . . . . . . . . . . . . . . . . . . 93
4.8.3. LastRebootReason . . . . . . . . . . . . . . . . . . 93
4.8.4. MacType . . . . . . . . . . . . . . . . . . . . . . . 93
4.8.5. PreferredACs . . . . . . . . . . . . . . . . . . . . 93
4.8.6. RebootCount . . . . . . . . . . . . . . . . . . . . . 93
4.8.7. Static ACL Table . . . . . . . . . . . . . . . . . . 93
4.8.8. Static IP Address . . . . . . . . . . . . . . . . . . 93
4.8.9. WTPLinkFailureCount . . . . . . . . . . . . . . . . . 93
4.8.10. WTPLocation . . . . . . . . . . . . . . . . . . . . . 93
4.8.11. WTPName . . . . . . . . . . . . . . . . . . . . . . . 94
5. CAPWAP Discovery Operations . . . . . . . . . . . . . . . . . 95
5.1. Discovery Request Message . . . . . . . . . . . . . . . . 95
5.2. Discovery Response Message . . . . . . . . . . . . . . . 96
5.3. Primary Discovery Request Message . . . . . . . . . . . . 97
5.4. Primary Discovery Response . . . . . . . . . . . . . . . 98
6. CAPWAP Join Operations . . . . . . . . . . . . . . . . . . . 100
6.1. Join Request . . . . . . . . . . . . . . . . . . . . . . 100
6.2. Join Response . . . . . . . . . . . . . . . . . . . . . . 101
7. Control Channel Management . . . . . . . . . . . . . . . . . 103
7.1. Echo Request . . . . . . . . . . . . . . . . . . . . . . 103
7.2. Echo Response . . . . . . . . . . . . . . . . . . . . . . 103
8. WTP Configuration Management . . . . . . . . . . . . . . . . 105
8.1. Configuration Consistency . . . . . . . . . . . . . . . . 105
8.1.1. Configuration Flexibility . . . . . . . . . . . . . . 106
8.2. Configuration Status . . . . . . . . . . . . . . . . . . 106
8.3. Configuration Status Response . . . . . . . . . . . . . . 107
8.4. Configuration Update Request . . . . . . . . . . . . . . 108
8.5. Configuration Update Response . . . . . . . . . . . . . . 109
8.6. Change State Event Request . . . . . . . . . . . . . . . 109
8.7. Change State Event Response . . . . . . . . . . . . . . . 110
8.8. Clear Configuration Request . . . . . . . . . . . . . . . 111
8.9. Clear Configuration Response . . . . . . . . . . . . . . 111
9. Device Management Operations . . . . . . . . . . . . . . . . 112
9.1. Firmware Management . . . . . . . . . . . . . . . . . . . 112
9.1.1. Image Data Request . . . . . . . . . . . . . . . . . 115
9.1.2. Image Data Response . . . . . . . . . . . . . . . . . 116
9.2. Reset Request . . . . . . . . . . . . . . . . . . . . . . 117
9.3. Reset Response . . . . . . . . . . . . . . . . . . . . . 117
9.4. WTP Event Request . . . . . . . . . . . . . . . . . . . . 118
9.5. WTP Event Response . . . . . . . . . . . . . . . . . . . 119
9.6. Data Transfer Request . . . . . . . . . . . . . . . . . . 119
9.7. Data Transfer Response . . . . . . . . . . . . . . . . . 119
10. Station Session Management . . . . . . . . . . . . . . . . . 121
10.1. Station Configuration Request . . . . . . . . . . . . . . 121
10.2. Station Configuration Response . . . . . . . . . . . . . 121
11. NAT Considerations . . . . . . . . . . . . . . . . . . . . . 122
12. Security Considerations . . . . . . . . . . . . . . . . . . . 124
12.1. CAPWAP Security . . . . . . . . . . . . . . . . . . . . . 124
12.1.1. Converting Protected Data into Unprotected Data . . . 125
12.1.2. Converting Unprotected Data into Protected Data
(Insertion) . . . . . . . . . . . . . . . . . . . . . 125
12.1.3. Deletion of Protected Records . . . . . . . . . . . . 125
12.1.4. Insertion of Unprotected Records . . . . . . . . . . 125
12.2. Session ID Security . . . . . . . . . . . . . . . . . . . 125
12.3. Discovery Attacks . . . . . . . . . . . . . . . . . . . . 126
12.4. Interference with a DTLS Session . . . . . . . . . . . . 126
12.5. Use of Preshared Keys in CAPWAP . . . . . . . . . . . . . 126
12.6. Use of Certificates in CAPWAP . . . . . . . . . . . . . . 127
12.7. AAA Security . . . . . . . . . . . . . . . . . . . . . . 128
13. Management Considerations . . . . . . . . . . . . . . . . . . 129
14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 130
14.1. CAPWAP Message Types . . . . . . . . . . . . . . . . . . 130
15. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 131
16. References . . . . . . . . . . . . . . . . . . . . . . . . . 132
16.1. Normative References . . . . . . . . . . . . . . . . . . 132
16.2. Informational References . . . . . . . . . . . . . . . . 133
16.3. Informational References . . . . . . . . . . . . . . . . 133
Editors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 134
Intellectual Property and Copyright Statements . . . . . . . . . 135
1. Introduction 1. Introduction
This document describes the CAPWAP Protocol, a standard, This document describes the CAPWAP Protocol, a standard,
interoperable protocol which enables an Access Controller (AC) to interoperable protocol which enables an Access Controller (AC) to
manage a collection of Wireless Termination Points (WTPs). The manage a collection of Wireless Termination Points (WTPs). The
CAPWAP protocol is defined to be independent of layer 2 technology. CAPWAP protocol is defined to be independent of layer 2 technology.
The emergence of centralized IEEE 802.11 Wireless Local Area Network The emergence of centralized IEEE 802.11 Wireless Local Area Network
(WLAN) architectures, in which simple IEEE 802.11 WTPs are managed by (WLAN) architectures, in which simple IEEE 802.11 WTPs are managed by
an Access Controller (AC) suggested that a standards based, an Access Controller (AC) suggested that a standards based,
interoperable protocol could radically simplify the deployment and interoperable protocol could radically simplify the deployment and
management of wireless networks. WTPs require a set of dynamic management of wireless networks. WTPs require a set of dynamic
management and control functions related to their primary task of management and control functions related to their primary task of
connecting the wireless and wired mediums. Traditional protocols for connecting the wireless and wired mediums. Traditional protocols for
managing WTPs are either manual static configuration via HTTP, managing WTPs are either manual static configuration via HTTP,
proprietary Layer 2 specific or non-existent (if the WTPs are self- proprietary Layer 2 specific or non-existent (if the WTPs are self-
contained). An IEEE 802.11 binding is defined in [14] to support use contained). An IEEE 802.11 binding is defined in [12] to support use
of the CAPWAP protocol with IEEE 802.11 WLAN networks. of the CAPWAP protocol with IEEE 802.11 WLAN networks.
CAPWAP assumes a network configuration consisting of multiple WTPs CAPWAP assumes a network configuration consisting of multiple WTPs
communicating via the Internet Protocol (IP) to an AC. WTPs are communicating via the Internet Protocol (IP) to an AC. WTPs are
viewed as remote RF interfaces controlled by the AC. The CAPWAP viewed as remote RF interfaces controlled by the AC. The CAPWAP
protocol supports two modes of operation: Split and Local MAC. In protocol supports two modes of operation: Split and Local MAC. In
Split MAC mode all L2 wireless data and management frames are Split MAC mode all L2 wireless data and management frames are
encapsulated via the CAPWAP protocol and exchanged between the AC and encapsulated via the CAPWAP protocol and exchanged between the AC and
the WTP. As shown in Figure 1, the wireless frames received from a the WTP. As shown in Figure 1, the wireless frames received from a
mobile device, which is referred to in this specification as a mobile device, which is referred to in this specification as a
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1.3. Contributing Authors 1.3. Contributing Authors
This section lists and acknowledges the authors of significant text This section lists and acknowledges the authors of significant text
and concepts included in this specification. and concepts included in this specification.
The CAPWAP Working Group selected the Lightweight Access Point The CAPWAP Working Group selected the Lightweight Access Point
Protocol (LWAPP) [add reference, when available] to be used as the Protocol (LWAPP) [add reference, when available] to be used as the
basis of the CAPWAP protocol specification. The following people are basis of the CAPWAP protocol specification. The following people are
authors of the LWAPP document: authors of the LWAPP document:
Bob O'Hara, Cisco Systems, Inc.,170 West Tasman Drive, San Jose, CA 95134 Bob O'Hara, Cisco Systems, Inc.
170 West Tasman Drive, San Jose, CA 95134
Phone: +1 408-853-5513, Email: bob.ohara@cisco.com Phone: +1 408-853-5513, Email: bob.ohara@cisco.com
Pat Calhoun, Cisco Systems, Inc., 170 West Tasman Drive, San Jose, CA 95134 Pat Calhoun, Cisco Systems, Inc.
170 West Tasman Drive, San Jose, CA 95134
Phone: +1 408-853-5269, Email: pcalhoun@cisco.com Phone: +1 408-853-5269, Email: pcalhoun@cisco.com
Rohit Suri, Cisco Systems, Inc., 170 West Tasman Drive, San Jose, CA 95134 Rohit Suri, Cisco Systems, Inc.
170 West Tasman Drive, San Jose, CA 95134
Phone: +1 408-853-5548, Email: rsuri@cisco.com Phone: +1 408-853-5548, Email: rsuri@cisco.com
Nancy Cam Winget, Cisco Systems, Inc., 170 West Tasman Drive, San Jose, CA 95134 Nancy Cam Winget, Cisco Systems, Inc.
170 West Tasman Drive, San Jose, CA 95134
Phone: +1 408-853-0532, Email: ncamwing@cisco.com Phone: +1 408-853-0532, Email: ncamwing@cisco.com
Scott Kelly, Aruba Networks, 1322 Crossman Ave, Sunnyvale, CA 94089 Scott Kelly, Aruba Networks
1322 Crossman Ave, Sunnyvale, CA 94089
Phone: +1 408-754-8408, Email: skelly@arubanetworks.com Phone: +1 408-754-8408, Email: skelly@arubanetworks.com
Michael Glenn Williams, Nokia, Inc., 313 Fairchild Drive, Mountain View, CA 94043 Michael Glenn Williams, Nokia, Inc.
313 Fairchild Drive, Mountain View, CA 94043
Phone: +1 650-714-7758, Email: Michael.G.Williams@Nokia.com Phone: +1 650-714-7758, Email: Michael.G.Williams@Nokia.com
Sue Hares, Nexthop Technologies, Inc., 825 Victors Way, Suite 100, Ann Arbor, MI 48108 Sue Hares, Nexthop Technologies, Inc.
825 Victors Way, Suite 100, Ann Arbor, MI 48108
Phone: +1 734 222 1610, Email: shares@nexthop.com Phone: +1 734 222 1610, Email: shares@nexthop.com
DTLS is used as the security solution for the CAPWAP protocol. The DTLS is used as the security solution for the CAPWAP protocol. The
following people are authors of significant DTLS-related text following people are authors of significant DTLS-related text
included in this document: included in this document:
Scott Kelly, Aruba Networks, 1322 Crossman Ave, Sunnyvale, CA 94089 Scott Kelly, Aruba Networks
1322 Crossman Ave, Sunnyvale, CA 94089
Phone: +1 408-754-8408, Email: skelly@arubanetworks.com Phone: +1 408-754-8408, Email: skelly@arubanetworks.com
Eric Rescorla, Network Resonance, 2483 El Camino Real, #212,Palo Alto CA, 94303 Eric Rescorla, Network Resonance
2483 El Camino Real, #212,Palo Alto CA, 94303
Email: ekr@networkresonance.com Email: ekr@networkresonance.com
The concept of using DTLS to secure the CAPWAP protocol was part of The concept of using DTLS to secure the CAPWAP protocol was part of
the Secure Light Access Point Protocol (SLAPP) proposal [add the Secure Light Access Point Protocol (SLAPP) proposal [add
reference when available]. The following people are authors of the reference when available]. The following people are authors of the
SLAPP proposal: SLAPP proposal:
Partha Narasimhan, Aruba Networks, 1322 Crossman Ave, Sunnyvale, CA 94089 Partha Narasimhan, Aruba Networks
1322 Crossman Ave, Sunnyvale, CA 94089
Phone: +1 408-480-4716, Email: partha@arubanetworks.com Phone: +1 408-480-4716, Email: partha@arubanetworks.com
Dan Harkins, Tropos Networks, 555 Del Rey Avenue, Sunnyvale, CA, 95085 Dan Harkins, Tropos Networks
555 Del Rey Avenue, Sunnyvale, CA, 95085
Phone: +1 408 470 7372, Email: dharkins@tropos.com Phone: +1 408 470 7372, Email: dharkins@tropos.com
Subbu Ponnuswamy, Aruba Networks, 1322 Crossman Ave, Sunnyvale, CA 94089 Subbu Ponnuswamy, Aruba Networks
1322 Crossman Ave, Sunnyvale, CA 94089
Phone: +1 408-754-1213, Email: subbu@arubanetworks.com Phone: +1 408-754-1213, Email: subbu@arubanetworks.com
The following individuals contributed significant security related The following individuals contributed significant security related
text to the draft: text to the draft:
T. Charles Clancy, Laboratory for Telecommunications Sciences, T. Charles Clancy, Laboratory for Telecommunications Sciences,
8080 Greenmead Drive, College Park, MD 20740 8080 Greenmead Drive, College Park, MD 20740
Phone: +1 240-373-5069, Email: clancy@ltsnet.net Phone: +1 240-373-5069, Email: clancy@ltsnet.net
Scott Kelly, Aruba Networks, 1322 Crossman Ave, Sunnyvale, CA 94089 Scott Kelly, Aruba Networks
1322 Crossman Ave, Sunnyvale, CA 94089
Phone: +1 408-754-8408, Email: skelly@arubanetworks.com Phone: +1 408-754-8408, Email: skelly@arubanetworks.com
1.4. Terminology 1.4. Terminology
Access Controller (AC): The network entity that provides WTPs access Access Controller (AC): The network entity that provides WTPs access
to the network infrastructure in the data plane, control plane, to the network infrastructure in the data plane, control plane,
management plane, or a combination therein. management plane, or a combination therein.
CAPWAP Control Channel: A bi-directional flow defined by the AC IP
Address, WTP IP Address, AC control port, WTP control port and the
transport-layer protocol (UDP or UDP-Lite) over which CAPWAP control
packets are sent and received.
CAPWAP Data Channel: A bi-directional flow defined by the AC IP
Address, WTP IP Address, AC data port, WTP data port, and the
transport-layer protocol (UDP or UDP-Lite) over which CAPWAP data
packets are sent and received.
Station (STA): A device that contains an IEEE 802.11 conformant Station (STA): A device that contains an IEEE 802.11 conformant
medium access control (MAC) and physical layer (PHY) interface to the medium access control (MAC) and physical layer (PHY) interface to the
wireless medium (WM). wireless medium (WM).
Wireless Termination Point (WTP): The physical or network entity that Wireless Termination Point (WTP): The physical or network entity that
contains an RF antenna and wireless PHY to transmit and receive contains an RF antenna and wireless PHY to transmit and receive
station traffic for wireless access networks. station traffic for wireless access networks.
This document uses additional terminology defined in [8]. This document uses additional terminology defined in [15].
2. Protocol Overview 2. Protocol Overview
The CAPWAP protocol is a generic protocol defining AC and WTP control The CAPWAP protocol is a generic protocol defining AC and WTP control
and data plane communication via a CAPWAP protocol transport and data plane communication via a CAPWAP protocol transport
mechanism. CAPWAP control messages, and optionally CAPWAP data mechanism. CAPWAP control messages, and optionally CAPWAP data
messages, are secured using Datagram Transport Layer Security (DTLS) messages, are secured using Datagram Transport Layer Security (DTLS)
[7]. DTLS is a standards-track IETF protocol based upon TLS. The [7]. DTLS is a standards-track IETF protocol based upon TLS. The
underlying security-related protocol mechanisms of TLS have been underlying security-related protocol mechanisms of TLS have been
successfully deployed for many years. successfully deployed for many years.
skipping to change at page 12, line 16 skipping to change at page 9, line 16
The CAPWAP protocol provides for a keep alive feature that preserves The CAPWAP protocol provides for a keep alive feature that preserves
the communication channel between the WTP and AC. If the AC fails to the communication channel between the WTP and AC. If the AC fails to
appear alive, the WTP will try to discover a new AC. appear alive, the WTP will try to discover a new AC.
2.1. Wireless Binding Definition 2.1. Wireless Binding Definition
The CAPWAP protocol is independent of a specific WTP radio The CAPWAP protocol is independent of a specific WTP radio
technology. Elements of the CAPWAP protocol are designed to technology. Elements of the CAPWAP protocol are designed to
accommodate the specific needs of each wireless technology in a accommodate the specific needs of each wireless technology in a
standard way. Implementation of the CAPWAP protocol for a particular standard way. Implementation of the CAPWAP protocol for a particular
wireless technology must follow the binding requirements defined for wireless technology MUST follow the binding requirements defined for
that technology. that technology.
When defining a binding for wireless technologies, the authors MUST When defining a binding for wireless technologies, the authors MUST
include any necessary definitions for technology-specific messages include any necessary definitions for technology-specific messages
and all technology-specific message elements for those messages. At and all technology-specific message elements for those messages. At
a minimum, a binding MUST provide: a minimum, a binding MUST provide:
1 - The definition for a binding-specific Statistics message 1 - The definition for a binding-specific Statistics message
element, carried in the WTP Event Request message element, carried in the WTP Event Request message
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Discovery, Primary Discovery and Join Request and Response Discovery, Primary Discovery and Join Request and Response
messages, indicating the binding specific radio types supported at messages, indicating the binding specific radio types supported at
the WTP and AC. the WTP and AC.
If technology specific message elements are required for any of the If technology specific message elements are required for any of the
existing CAPWAP messages defined in this specification, they MUST existing CAPWAP messages defined in this specification, they MUST
also be defined in the technology binding document. also be defined in the technology binding document.
The naming of binding-specific message elements MUST begin with the The naming of binding-specific message elements MUST begin with the
name of the technology type, e.g., the binding for IEEE 802.11, name of the technology type, e.g., the binding for IEEE 802.11,
provided in [14], begins with "IEEE 802.11". provided in [12], begins with "IEEE 802.11".
The CAPWAP binding concept is also used in any future specifications The CAPWAP binding concept is also used in any future specifications
that add functionality to either the base CAPWAP protocol that add functionality to either the base CAPWAP protocol
specification, or any published CAPWAP binding specification. A specification, or any published CAPWAP binding specification. A
separate WTP Radio Information message element MUST be created to separate WTP Radio Information message element MUST be created to
properly advertise support for the specification. This mechanism properly advertise support for the specification. This mechanism
allows for future protocol extensibility, while providing the allows for future protocol extensibility, while providing the
necessary capabilities advertisement, through the WTP Radio necessary capabilities advertisement, through the WTP Radio
Information message element, to ensure WTP/AC interoperability. Information message element, to ensure WTP/AC interoperability.
2.2. CAPWAP Session Establishment Overview 2.2. CAPWAP Session Establishment Overview
This section describes the session establishment process message This section describes the session establishment process message
exchanges in the ideal case. The annotated ladder diagram shows the exchanges in the ideal case. The annotated ladder diagram shows the
AC on the right, the WTP on the left, and assumes the use of AC on the right, the WTP on the left, and assumes the use of
certificates for DTLS authentication. The CAPWAP Protocol State certificates for DTLS authentication. The CAPWAP Protocol State
Machine is described in detail in Section 2.3. Machine is described in detail in Section 2.3. Note that DTLS allows
certain messages to be aggregated into a single frame, which is
denoted via an asterix in the following figure.
============ ============ ============ ============
WTP AC WTP AC
============ ============ ============ ============
[----------- begin optional discovery ------------] [----------- begin optional discovery ------------]
Discover Request ------> Discover Request
<------ Discover Response ------------------------------------>
Discover Response
<------------------------------------
[----------- end optional discovery ------------] [----------- end optional discovery ------------]
(--- begin DTLS handshake ---) (-- begin DTLS handshake --)
ClientHello ------> ClientHello
<------ HelloVerifyRequest ------------------------------------>
(with cookie) HelloVerifyRequest (with cookie)
<------------------------------------
ClientHello ------> ClientHello (with cookie)
(with cookie) ------------------------------------>
<------ ServerHello ServerHello,
<------ Certificate Certificate,
<------ ServerHelloDone ServerHelloDone*
<------------------------------------
(WTP callout for AC authorization) (-- WTP callout for AC authorization --)
Certificate* Certificate (optional),
ClientKeyExchange ClientKeyExchange,
CertificateVerify* CertificateVerify (optional),
[ChangeCipherSpec] ChangeCipherSpec,
Finished ------> Finished*
------------------------------------>
(AC callout for WTP (-- AC callout for WTP authorization --)
authorization) ChangeCipherSpec,
Finished*
<------------------------------------
[ChangeCipherSpec] (-- DTLS session is established now --)
<------ Finished
(--- DTLS session is established now ---) Join Request
------------------------------------>
Join Response
<------------------------------------
Join Request ------> (-- assume image is up to date --)
<------ Join Response
( ---assume image is up to date ---)
Configuration Status Request -------> Configuration Status Request
<------ Configuration Status Response ------------------------------------>
Configuration Status Response
<------------------------------------
(--- enter RUN state ---) (-- enter RUN state --)
: :
: :
Echo Request -------> Echo Request
<------ Echo Response ------------------------------------>
Echo Response
<------------------------------------
: :
: :
Event Request -------> Event Request
<------ Event Response ------------------------------------>
Event Response
<------------------------------------
: :
: :
At the end of the illustrated CAPWAP message exchange, the AC and WTP At the end of the illustrated CAPWAP message exchange, the AC and WTP
are securely exchanging CAPWAP control messages. This is an are securely exchanging CAPWAP control messages. This is an
idealized illustration, provided to clarify protocol operation. idealized illustration, provided to clarify protocol operation.
Section 2.3 provides a detailed description of the corresponding Section 2.3 provides a detailed description of the corresponding
state machine. state machine.
skipping to change at page 16, line 24 skipping to change at page 14, line 24
that cause them. This section does not discuss interactions between that cause them. This section does not discuss interactions between
DTLS- and CAPWAP-specific states. Those interactions, and DTLS- DTLS- and CAPWAP-specific states. Those interactions, and DTLS-
specific states and transitions, are discussed in Section 2.3.2. specific states and transitions, are discussed in Section 2.3.2.
Idle to Discovery (a): This transition occurs once device Idle to Discovery (a): This transition occurs once device
initialization is complete. initialization is complete.
WTP: The WTP enters the Discovery state prior to transmitting the WTP: The WTP enters the Discovery state prior to transmitting the
first Discovery Request message (see Section 5.1). Upon first Discovery Request message (see Section 5.1). Upon
entering this state, the WTP sets the DiscoveryInterval timer entering this state, the WTP sets the DiscoveryInterval timer
(see Section 4.6). The WTP resets the DiscoveryCount counter (see Section 4.7). The WTP resets the DiscoveryCount counter
to zero (0) (see Section 4.7). The WTP also clears all to zero (0) (see Section 4.8). The WTP also clears all
information from ACs it may have received during a previous information from ACs it may have received during a previous
Discovery phase. Discovery phase.
AC: The AC does not maintain state information for the WTP upon AC: The AC does not maintain state information for the WTP upon
reception of the Discovery Request message, but it SHOULD reception of the Discovery Request message, but it SHOULD
respond with a Discovery Response message (see Section 5.2). respond with a Discovery Response message (see Section 5.2).
This transition is a no-op for the AC. This transition is a no-op for the AC.
Idle to Sulking (b): This transition occurs to force the WTP and AC Idle to Sulking (b): This transition occurs to force the WTP and AC
to enter a quiet period to avoid repeatedly attempting to to enter a quiet period to avoid repeatedly attempting to
establish a connection. establish a connection.
WTP: The WTP enters this state when the FailedDTLSSessionCount or WTP: The WTP enters this state when the FailedDTLSSessionCount or
the FailedDTLSAuthFailCount counter reaches the FailedDTLSAuthFailCount counter reaches
MaxFailedDTLSSessionRetry variable (see Section 4.7). Upon MaxFailedDTLSSessionRetry variable (see Section 4.8). Upon
entering this state, the WTP MUST start the SilentInterval entering this state, the WTP MUST start the SilentInterval
timer. While in the Sulking state, all received CAPWAP and timer. While in the Sulking state, all received CAPWAP and
DTLS protocol messages received MUST be ignored. DTLS protocol messages received MUST be ignored.
AC: The AC enters this state with the specific WTP when the AC: The AC enters this state with the specific WTP when the
FailedDTLSSessionCount or the FailedDTLSAuthFailCount counter FailedDTLSSessionCount or the FailedDTLSAuthFailCount counter
reaches MaxFailedDTLSSessionRetry variable (see Section 4.7). reaches MaxFailedDTLSSessionRetry variable (see Section 4.8).
Upon entering this state, the AC MUST start the SilentInterval Upon entering this state, the AC MUST start the SilentInterval
timer. While in the Sulking state, all received CAPWAP and timer. While in the Sulking state, all received CAPWAP and
DTLS protocol messages received from the WTP MUST be ignored. DTLS protocol messages received from the WTP MUST be ignored.
Discovery to Discovery (2): In the Discovery state, the WTP Discovery to Discovery (2): In the Discovery state, the WTP
determines which AC to connect to. determines which AC to connect to.
WTP: This transition occurs when the DiscoveryInterval timer WTP: This transition occurs when the DiscoveryInterval timer
expires. If the WTP is configured with a list of ACs, it expires. If the WTP is configured with a list of ACs, it
transmits a Discovery Request message to every AC from which it transmits a Discovery Request message to every AC from which it
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messages. The WTP restarts the DiscoveryInterval timer messages. The WTP restarts the DiscoveryInterval timer
whenever it transmits Discovery Request messages. whenever it transmits Discovery Request messages.
AC: This is a no-op. AC: This is a no-op.
Discovery to Sulking (c): This transition occurs on a WTP when Discovery to Sulking (c): This transition occurs on a WTP when
Discovery or connectivity to the AC fails. Discovery or connectivity to the AC fails.
WTP: The WTP enters this state when the DiscoveryInterval timer WTP: The WTP enters this state when the DiscoveryInterval timer
expires or the DiscoveryCount variable is equal to the expires or the DiscoveryCount variable is equal to the
MaxDiscoveries variable (see Section 4.7). Upon entering this MaxDiscoveries variable (see Section 4.8). Upon entering this
state, the WTP MUST start the SilentInterval timer. While in state, the WTP MUST start the SilentInterval timer. While in
the Sulking state, all received CAPWAP protocol messages the Sulking state, all received CAPWAP protocol messages
received MUST be ignored. received MUST be ignored.
AC: This is a no-op. AC: This is a no-op.
Sulking to Idle (d): This transition occurs on a WTP when it must Sulking to Idle (d): This transition occurs on a WTP when it must
restart the discovery phase. restart the discovery phase.
WTP: The WTP enters this state when the SilentInterval timer (see WTP: The WTP enters this state when the SilentInterval timer (see
Section 4.6) expires. The FailedDTLSSessionCount, Section 4.7) expires. The FailedDTLSSessionCount,
DiscoveryCount and FailedDTLSAuthFailCount counters are reset DiscoveryCount and FailedDTLSAuthFailCount counters are reset
to zero. to zero.
AC: The AC enters this state when the SilentInterval timer (see AC: The AC enters this state when the SilentInterval timer (see
Section 4.6) expires. The FailedDTLSSessionCount, Section 4.7) expires. The FailedDTLSSessionCount,
DiscoveryCount and FailedDTLSAuthFailCount counters are reset DiscoveryCount and FailedDTLSAuthFailCount counters are reset
to zero. to zero.
Sulking to Sulking (3): The Sulking state provides the silent Sulking to Sulking (3): The Sulking state provides the silent
period, minimizing the possibility for Denial of Service (DoS) period, minimizing the possibility for Denial of Service (DoS)
attacks. attacks.
WTP: All packets received from the AC while in the sulking state WTP: All packets received from the AC while in the sulking state
are ignored. are ignored.
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DTLSEstablished notification (see Section 2.3.2.2), indicating DTLSEstablished notification (see Section 2.3.2.2), indicating
that the DTLS session was successfully established. When this that the DTLS session was successfully established. When this
notification is received, the FailedDTLSSessionCount counter is notification is received, the FailedDTLSSessionCount counter is
set to zero. set to zero.
AC: This state transition occurs when the AC receives the AC: This state transition occurs when the AC receives the
DTLSEstablished notification (see Section 2.3.2.2), indicating DTLSEstablished notification (see Section 2.3.2.2), indicating
that the DTLS session was successfully established. When this that the DTLS session was successfully established. When this
notification is received, the FailedDTLSSessionCount counter is notification is received, the FailedDTLSSessionCount counter is
set to zero, and the WaitJoin timer is started (see set to zero, and the WaitJoin timer is started (see
Section 4.6). Section 4.7).
Join to DTLS Teardown (p): This transition occurs when the join Join to DTLS Teardown (p): This transition occurs when the join
process failed. process failed.
WTP: This state transition occurs when the WTP receives a Join WTP: This state transition occurs when the WTP receives a Join
Response message with a Result Code message element containing Response message with a Result Code message element containing
an error, if the Image Identifier provided by the AC in the an error, if the Image Identifier provided by the AC in the
Join Response message differs from the WTP's currently running Join Response message differs from the WTP's currently running
firmware version and the WTP has the requested image in its firmware version and the WTP has the requested image in its
non-volatile memory, or if the WaitDTLS timer expires. This non-volatile memory, or if the WaitDTLS timer expires. This
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Join to Image Data (r): This state transition is used by the WTP and Join to Image Data (r): This state transition is used by the WTP and
the AC to download executable firmware. the AC to download executable firmware.
WTP: The WTP enters the Image Data state when it receives a WTP: The WTP enters the Image Data state when it receives a
successful Join Response message and determines and the successful Join Response message and determines and the
included Image Identifier message element is not the same as included Image Identifier message element is not the same as
its currently running image. The WTP also detects that the its currently running image. The WTP also detects that the
requested image version is not currently available in the WTP's requested image version is not currently available in the WTP's
non-volatile storage (see Section 9.1 for a full description of non-volatile storage (see Section 9.1 for a full description of
the firmware download process). The WTP transmits the Image the firmware download process). The WTP initializes the
EchoInterval timer (see Section 4.7), and transmits the Image
Data Request message (see Section 9.1.1) requesting the start Data Request message (see Section 9.1.1) requesting the start
of the firwware download. of the firmware download.
AC: This state transition occurs when the AC receives the Image AC: This state transition occurs when the AC receives the Image
Data Request message from the WTP. The AC must transmit an Data Request message from the WTP. The AC MUST transmit an
Image Data Response message (see Section 9.1.2) to the WTP, Image Data Response message (see Section 9.1.2) to the WTP,
which includes a portion of the firmware. which includes a portion of the firmware. The AC MUST start
the NeighborDeadInterval timer (see Section 4.7).
Join to Configure (q): This state transition is used by the WTP and Join to Configure (q): This state transition is used by the WTP and
the AC to exchange configuration information. the AC to exchange configuration information.
WTP: The WTP enters the Configure state when it receives a WTP: The WTP enters the Configure state when it receives a
successful Join Response, and determines that the included successful Join Response, and determines that the included
Image Identifier message element is the same as its currently Image Identifier message element is the same as its currently
running image. The WTP transmits the Configuration Status running image. The WTP transmits the Configuration Status
message (see Section 8.2) to the AC with message elements message (see Section 8.2) to the AC with message elements
describing its current configuration. The WTP also starts the describing its current configuration. The WTP also starts the
ResponseTimeout timer (see Section 4.6). ResponseTimeout timer (see Section 4.7).
AC: This state transition occurs immediately after the AC AC: This state transition occurs immediately after the AC
transmits the Join Response message to the WTP. If the AC transmits the Join Response message to the WTP. If the AC
receives the Configuration Status message from the WTP, the AC receives the Configuration Status message from the WTP, the AC
must transmit a Configuration Status Response message (see MUST transmit a Configuration Status Response message (see
Section 8.3) to the WTP, and may include specific message Section 8.3) to the WTP, and MAY include specific message
elements to override the WTP's configuration. The WTP also elements to override the WTP's configuration. The WTP also
starts the ChangeStatePendingTimer timer (see Section 4.6). starts the ChangeStatePendingTimer timer (see Section 4.7).
Configure to Reset (s): This state transition is used to reset the Configure to Reset (s): This state transition is used to reset the
connection either due to an error during the configuration phase, connection either due to an error during the configuration phase,
or when the WTP determines it needs to reset in order for the new or when the WTP determines it needs to reset in order for the new
configuration to take effect. configuration to take effect.
WTP: The WTP enters the Reset state when it receives a WTP: The WTP enters the Reset state when it receives a
Configuration Status Response indicating an error or when it Configuration Status Response indicating an error or when it
determines that a reset of the WTP is required, due to the determines that a reset of the WTP is required, due to the
characteristics of a new configuration. characteristics of a new configuration.
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following DTLS notifications: DTLSAborted, following DTLS notifications: DTLSAborted,
DTLSReassemblyFailure or DTLSPeerDisconnect (see DTLSReassemblyFailure or DTLSPeerDisconnect (see
Section 2.3.2.2). The WTP MAY tear down the DTLS session if it Section 2.3.2.2). The WTP MAY tear down the DTLS session if it
receives frequent DTLSDecapFailure notifications. receives frequent DTLSDecapFailure notifications.
Configure to Data Check (t): This state transition occurs when the Configure to Data Check (t): This state transition occurs when the
WTP and AC confirm the configuration. WTP and AC confirm the configuration.
WTP: The WTP enters this state when it receives a successful WTP: The WTP enters this state when it receives a successful
Configuration Status Response message from the AC. The WTP Configuration Status Response message from the AC. The WTP
initializes the EchoInterval timer (see Section 4.6), and initializes the EchoInterval timer (see Section 4.7), and
transmits the Change State Event Request message (see transmits the Change State Event Request message (see
Section 8.6). Section 8.6).
AC: This state transition occurs when the AC receives the Change AC: This state transition occurs when the AC receives the Change
State Event Request message (see Section 8.6) from the WTP. State Event Request message (see Section 8.6) from the WTP.
The AC responds with a Change State Event Response message (see The AC responds with a Change State Event Response message (see
Section 8.7). The AC must start the NeighborDeadInterval timer Section 8.7). The AC MUST start the NeighborDeadInterval timer
(see Section 4.6). (see Section 4.7).
Data Check to Run (u): This state transition occurs when the linkage Data Check to Run (u): This state transition occurs when the linkage
between the control and data channels has occured, causing the WTP between the control and data channels has occured, causing the WTP
and AC to enter their normal state of operation. and AC to enter their normal state of operation.
WTP: The WTP enters this state when it receives a successful WTP: The WTP enters this state when it receives a successful
Change State Event Response message from the AC. The WTP Change State Event Response message from the AC. The WTP
initiates the data channel, which MAY require the establishment initiates the data channel, which MAY require the establishment
of a DTLS session, starts the DataChannelKeepAlive timer (see of a DTLS session, starts the DataChannelKeepAlive timer (see
Section 4.6) and transmits a Data Channel Keep Alive packet Section 4.7) and transmits a Data Channel Keep Alive packet
(see Section 4.3.1). The WTP then starts the (see Section 4.4.1). The WTP then starts the
DataChannelDeadInterval timer (see Section 4.6). DataChannelDeadInterval timer (see Section 4.7).
AC: This state transition occurs when the AC receives the Data AC: This state transition occurs when the AC receives the Data
Channel Keep Alive packet (see Section 4.3.1), with a Session Channel Keep Alive packet (see Section 4.4.1), with a Session
ID message element matching that included by the WTP in the ID message element matching that included by the WTP in the
Join Request message. Note that if AC policy is to require the Join Request message. Note that if AC policy is to require the
data channel to be encrypted, this process would also require data channel to be encrypted, this process would also require
the establishment of a data channel DTLS session. Upon the establishment of a data channel DTLS session. Upon
receiving the Data Channel Keep Alive packet, the AC transmits receiving the Data Channel Keep Alive packet, the AC transmits
its own Data Channel Keep Alive packet. its own Data Channel Keep Alive packet.
Run to DTLS Teardown (u): This state transition occurs when an error Run to DTLS Teardown (u): This state transition occurs when an error
has occured in the DTLS stack, causing the DTLS session to be has occured in the DTLS stack, causing the DTLS session to be
torndown. torndown.
WTP: The WTP enters this state when it receives one of the WTP: The WTP enters this state when it receives one of the
following DTLS notifications: DTLSAborted, following DTLS notifications: DTLSAborted,
DTLSReassemblyFailure or DTLSPeerDisconnect (see DTLSReassemblyFailure or DTLSPeerDisconnect (see
Section 2.3.2.2). The WTP MAY tear down the DTLS session if it Section 2.3.2.2). The WTP MAY tear down the DTLS session if it
receives frequent DTLSDecapFailure notifications. The WTP also receives frequent DTLSDecapFailure notifications. The WTP also
transitions to this state if the underlying reliable transitions to this state if the underlying reliable
transport's RetransmitCount counter has reached the transport's RetransmitCount counter has reached the
MaxRetransmit variable (see Section 4.6). MaxRetransmit variable (see Section 4.7).
AC: The AC enters this state when it receives one of the AC: The AC enters this state when it receives one of the
following DTLS notifications: DTLSAborted, following DTLS notifications: DTLSAborted,
DTLSReassemblyFailure or DTLSPeerDisconnect (see DTLSReassemblyFailure or DTLSPeerDisconnect (see
Section 2.3.2.2). The WTP MAY tear down the DTLS session if it Section 2.3.2.2). The WTP MAY tear down the DTLS session if it
receives frequent DTLSDecapFailure notifications. The AC receives frequent DTLSDecapFailure notifications. The AC
transitions to this state if the underlying reliable transitions to this state if the underlying reliable
transport's RetransmitCount counter has reached the transport's RetransmitCount counter has reached the
MaxRetransmit variable (see Section 4.6). MaxRetransmit variable (see Section 4.7).
Run to Run (5): This is the normal state of operation. Run to Run (5): This is the normal state of operation.
WTP: This is the WTP's normal state of operation. There are many WTP: This is the WTP's normal state of operation. There are many
events that result this state transition: events that result this state transition:
Configuration Update: The WTP receives a Configuration Update Configuration Update: The WTP receives a Configuration Update
Request message(see Section 8.4). The WTP MUST respond with Request message(see Section 8.4). The WTP MUST respond with
a Configuration Update Response message (see Section 8.5). a Configuration Update Response message (see Section 8.5).
skipping to change at page 28, line 36 skipping to change at page 26, line 36
o DTLSAuthenticateFail is sent when DTLS session establishment o DTLSAuthenticateFail is sent when DTLS session establishment
failed due to an authentication error. When this notification is failed due to an authentication error. When this notification is
received, the FailedDTLSAuthFailCount counter is incremented. received, the FailedDTLSAuthFailCount counter is incremented.
o DTLSAborted is sent to the CAPWAP component to indicate that o DTLSAborted is sent to the CAPWAP component to indicate that
session abort (as requested by CAPWAP) is complete; this occurs to session abort (as requested by CAPWAP) is complete; this occurs to
confirm a DTLS session abort, or when the WaitDTLS timer expires. confirm a DTLS session abort, or when the WaitDTLS timer expires.
When this notification is received, the WaitDTLS timer is stopped. When this notification is received, the WaitDTLS timer is stopped.
o DTLSReassemblyFailure may be sent to the CAPWAP component to o DTLSReassemblyFailure MAY be sent to the CAPWAP component to
indicate DTLS fragment reassembly failure. indicate DTLS fragment reassembly failure.
o DTLSDecapFailure may be sent to the CAPWAP module to indicate a o DTLSDecapFailure MAY be sent to the CAPWAP module to indicate a
decapsulation failure. DTLSDecapFailure may be sent to the CAPWAP decapsulation failure. DTLSDecapFailure MAY be sent to the CAPWAP
module to indicate an encryption/authentication failure. This module to indicate an encryption/authentication failure. This
notification is intended for informative purposes only, and is not notification is intended for informative purposes only, and is not
intended to cause a change in the CAPWAP state machine (see intended to cause a change in the CAPWAP state machine (see
Section 12.4). Section 12.4).
o DTLSPeerDisconnect is sent to the CAPWAP component to indicate the o DTLSPeerDisconnect is sent to the CAPWAP component to indicate the
DTLS session has been torn down. Note that this notification is DTLS session has been torn down. Note that this notification is
only received if the DTLS session has been established. only received if the DTLS session has been established.
2.4. Use of DTLS in the CAPWAP Protocol 2.4. Use of DTLS in the CAPWAP Protocol
skipping to change at page 29, line 23 skipping to change at page 27, line 23
available acceleration hardware, it is both convenient and forward- available acceleration hardware, it is both convenient and forward-
looking to maintain a modular distinction in this document. looking to maintain a modular distinction in this document.
This section describes a detailed walk-through of the interactions This section describes a detailed walk-through of the interactions
between the DTLS module and the CAPWAP module, via 'commands' (CAPWAP between the DTLS module and the CAPWAP module, via 'commands' (CAPWAP
to DTLS) and 'notifications' (DTLS to CAPWAP) as they would be to DTLS) and 'notifications' (DTLS to CAPWAP) as they would be
encountered during the normal course of operation. encountered during the normal course of operation.
2.4.1. DTLS Handshake Processing 2.4.1. DTLS Handshake Processing
Details of the DTLS handshake process are specified in [9]. This Details of the DTLS handshake process are specified in [8]. This
section describes the interactions between the DTLS session section describes the interactions between the DTLS session
establishment process and the CAPWAP protocol. Note that the establishment process and the CAPWAP protocol. Note that the
conceptual DTLS state is shown below to help understand the point at conceptual DTLS state is shown below to help understand the point at
which the DTLS states transition. In the normal case, the DTLS which the DTLS states transition. In the normal case, the DTLS
handshake will proceed as follows (NOTE: this example uses handshake will proceed as follows (NOTE: this example uses
certificates, but preshared keys are also supported): certificates, but preshared keys are also supported):
============ ============ ============ ============
WTP AC WTP AC
============ ============ ============ ============
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PSK does not necessarily imply authorization. PSK does not necessarily imply authorization.
If a single PSK is being used for multiple devices on a CAPWAP If a single PSK is being used for multiple devices on a CAPWAP
network, which is NOT RECOMMENDED, the PSK Hint and Identity can no network, which is NOT RECOMMENDED, the PSK Hint and Identity can no
longer be a MAC address, so appropriate hints and identities SHOULD longer be a MAC address, so appropriate hints and identities SHOULD
be selected to identify the group of devices to which the PSK is be selected to identify the group of devices to which the PSK is
provisioned. provisioned.
3. CAPWAP Transport 3. CAPWAP Transport
Communication between a WTP and an AC is established according to the Communication between a WTP and an AC is established using the
standard UDP client/server model. The CAPWAP protocol supports two standard UDP client/server model. The CAPWAP protocol supports both
different transport protocols. When used over IPv4, the UDP protocol UDP and UDP-Lite [11] transport protocols. The UDP protocol is used
is utilized. When CAPWAP is used over IPv6, the UDP-Lite RFC 3828 with IPv4. When CAPWAP is used over IPv6, the UDP-Lite protocol is
[13] is used. This section details the specifics of how the CAPWAP used. This section describes how the CAPWAP protocol is carried over
protocol works with IP. IP and UDP/UDP-Lite transport protocols.
3.1. UDP Transport 3.1. UDP Transport
One of the CAPWAP protocol requirements is to allow a WTP to reside One of the CAPWAP protocol requirements is to allow a WTP to reside
behind a firewall and/or Network Address Translation (NAT) device. behind a firewall and/or Network Address Translation (NAT) device.
Since the connection is initiated by the WTP (client) to the well- Since a CAPWAP session is initiated by the WTP (client) to the well-
known UDP port of the AC (server), the use of UDP is a logical known UDP port of the AC (server), the use of UDP is a logical
choice. The UDP checksum field in CAPWAP packets MUST be set to choice. The UDP checksum field in CAPWAP packets MUST be set to
zero. zero.
CAPWAP protocol control packets sent between the WTP and the AC use CAPWAP protocol control packets sent from the WTP to the AC use the
well known UDP port [to be IANA assigned]. CAPWAP protocol data CAPWAP control channel, as defined in Section 1.4. The CAPWAP
packets sent between the WTP and the AC use UDP port [to be IANA control port at the AC is the well known UDP port [to be IANA
assigned]. assigned]. The CAPWAP control port at the WTP can be any port
selected by the WTP.
CAPWAP protocol data packets sent from the WTP to the AC use the
CAPWAP data channel, as defined in Section 1.4. The CAPWAP data port
at the AC is the well known UDP port [to be IANA assigned]. The
CAPWAP data port at the WTP can be any port selected by the WTP.
3.2. UDP-Lite Transport 3.2. UDP-Lite Transport
When CAPWAP is run over IPv6, the UDP-Lite is used as the transport. When CAPWAP is run over IPv6, UDP-Lite is used as the transport
The reason for using UDP-Lite is because when UDP is run over IPv6, protocol, reducing the checksum processing required for each packet
it MUST NOT have its checksum field set to zero, which increases the (compared to UDP and IPv6). When UDP-Lite is used, the checksum
processing cost for each CAPWAP packet. When UDP-Lite is used, the field MUST have a coverage of 8 [11].
checksum field MUST have a coverage of 8 RFC 3828 [13].
As defined in RFC 3828 [13], UDP-Lite uses the same port assignments UDP-Lite uses the same port assignments as UDP.
as UDP.
3.3. AC Discovery 3.3. AC Discovery
The AC discovery phase allows the WTP to determine which ACs are The AC discovery phase allows the WTP to determine which ACs are
available, and chose the best AC with which to establish a CAPWAP available, and chose the best AC with which to establish a CAPWAP
session. The discovery phase occurs when the WTP enters the optional session. The discovery phase occurs when the WTP enters the optional
Discovery state. A WTP does not need to complete the AC Discovery Discovery state. A WTP does not need to complete the AC Discovery
phase if it uses a pre-configured AC. This section details the phase if it uses a pre-configured AC. This section details the
mechanism used by a WTP to dynamically discover candidate ACs. mechanism used by a WTP to dynamically discover candidate ACs.
A WTP and an AC will frequently not reside in the same IP subnet A WTP and an AC will frequently not reside in the same IP subnet
(broadcast domain). When this occurs, the WTP must be capable of (broadcast domain). When this occurs, the WTP must be capable of
discovering the AC, without requiring that multicast services are discovering the AC, without requiring that multicast services are
enabled in the network. enabled in the network.
When the WTP attempts to establish communication with an AC, it sends When the WTP attempts to establish communication with an AC, it sends
the Discovery Request message and receives the Discovery Response the Discovery Request message and receives the Discovery Response
message from the AC(s). The WTP must send the Discovery Request message from the AC(s). The WTP MUST send the Discovery Request
message to either the limited broadcast IP address (255.255.255.255), message to either the limited broadcast IP address (255.255.255.255),
a well known multicast address or to the unicast IP address of the a well known multicast address or to the unicast IP address of the
AC. For IPv6 networks, since broadcast does not exist, the use of AC. For IPv6 networks, since broadcast does not exist, the use of
"All ACs multicast address" is used instead. Upon receipt of the "All ACs multicast address" is used instead. Upon receipt of the
Discovery Request message, the AC sends a Discovery Response message Discovery Request message, the AC sends a Discovery Response message
to the unicast IP address of the WTP, regardless of whether the to the unicast IP address of the WTP, regardless of whether the
Discovery Request message was sent as a broadcast, multicast or Discovery Request message was sent as a broadcast, multicast or
unicast message. unicast message.
WTP use of a limited IP broadcast, multicast or unicast IP address is WTP use of a limited IP broadcast, multicast or unicast IP address is
implementation dependent. implementation dependent.
When a WTP transmits a Discovery Request message to a unicast When a WTP transmits a Discovery Request message to a unicast
address, the WTP must first obtain the IP address of the AC. Any address, the WTP must first obtain the IP address of the AC. Any
static configuration of an AC's IP address on the WTP non-volatile static configuration of an AC's IP address on the WTP non-volatile
storage is implementation dependent. However, additional dynamic storage is implementation dependent. However, additional dynamic
schemes are possible, for example: schemes are possible, for example:
DHCP: A comma delimited ASCII encoded list of AC IP addresses is DHCP: See [13] for more information on the use of DHCP to discover
embedded in DHCP code number TBD. An example of the actual format AC IP addresses.
of the vendor specific payload for IPv4 is of the form "10.1.1.1,
10.1.1.2".
DNS: The DNS name "CAPWAP-AC-Address" MAY be resolvable to one or DNS: The DNS name "CAPWAP-AC-Address" MAY be resolvable to one or
more AC addresses. more AC addresses.
An AC MAY also communicate alternative ACs to the WTP within the An AC MAY also communicate alternative ACs to the WTP within the
Discovery Response message through the AC IPv4 List (see Discovery Response message through the AC IPv4 List (see
Section 4.5.2) and AC IPv6 List (see Section 4.5.2). The addresses Section 4.6.2) and AC IPv6 List (see Section 4.6.2). The addresses
provided in these two message elements are intended to help the WTP provided in these two message elements are intended to help the WTP
discover additional ACs through means other than those listed above. discover additional ACs through means other than those listed above.
The AC Name with Index message element (see Section 4.5.5), is used The AC Name with Index message element (see Section 4.6.5), is used
to communicate a list of preferred ACs to the WTP. The WTP SHOULD to communicate a list of preferred ACs to the WTP. The WTP SHOULD
attempt to utilize the ACs listed in the order provided by the AC. attempt to utilize the ACs listed in the order provided by the AC.
The Name to IP Address mapping is handled via the Discovery message The Name to IP Address mapping is handled via the Discovery message
exchange, in which the ACs provide their identity in the AC Name (see exchange, in which the ACs provide their identity in the AC Name (see
Section 4.5.4) message element in the Discovery Response message. Section 4.6.4) message element in the Discovery Response message.
Once the WTP has received Discovery Response messages from the Once the WTP has received Discovery Response messages from the
candidate ACs, it MAY use other factors to determine the preferred candidate ACs, it MAY use other factors to determine the preferred
AC. For instance, each binding defines a WTP Radio Information AC. For instance, each binding defines a WTP Radio Information
message element (see Section 2.1), which the AC includes in Discovery message element (see Section 2.1), which the AC includes in Discovery
Response messages. The presence of one or more of these message Response messages. The presence of one or more of these message
elements is used to identify the CAPWAP bindings supported by the AC. elements is used to identify the CAPWAP bindings supported by the AC.
A WTP MAY connect to an AC based on the supported bindings A WTP MAY connect to an AC based on the supported bindings
advertised. advertised.
3.4. Fragmentation/Reassembly 3.4. Fragmentation/Reassembly
While fragmentation and reassembly services are provided by IP, the While fragmentation and reassembly services are provided by IP, the
CAPWAP protocol also provides such services. Environments where the CAPWAP protocol also provides such services. Environments where the
CAPWAP protocol is used involve firewall, NAT and "middle box" CAPWAP protocol is used involve firewall, NAT and "middle box"
devices, which tend to drop IP fragments to minimize possible DoS devices, which tend to drop IP fragments to minimize possible DoS
attacks. By providing fragmentation and reassembly at the attacks. By providing fragmentation and reassembly at the
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devices, which tend to drop IP fragments to minimize possible DoS devices, which tend to drop IP fragments to minimize possible DoS
attacks. By providing fragmentation and reassembly at the attacks. By providing fragmentation and reassembly at the
application layer, any fragmentation required due to the tunneling application layer, any fragmentation required due to the tunneling
component of the CAPWAP protocol becomes transparent to these component of the CAPWAP protocol becomes transparent to these
intermediate devices. Consequently, the CAPWAP protocol can be used intermediate devices. Consequently, the CAPWAP protocol can be used
in any network configuration. in any network configuration.
4. CAPWAP Packet Formats 4. CAPWAP Packet Formats
This section contains the CAPWAP protocol packet formats. A CAPWAP This section contains the CAPWAP protocol packet formats. A CAPWAP
protocol packet consists of a CAPWAP Transport Layer packet header protocol packet consists of one or more CAPWAP Transport Layer packet
followed by a CAPWAP message. The CAPWAP message can be either of headers followed by a CAPWAP message. The CAPWAP message can be
type Control or Data, where Control packets carry signaling, and Data either of type Control or Data, where Control packets carry
packets carry user payloads. The CAPWAP frame formats for CAPWAP signaling, and Data packets carry user payloads. The CAPWAP frame
Data packets, and for DTLS encapsulated CAPWAP Data and Control formats for CAPWAP Data packets, and for DTLS encapsulated CAPWAP
packets are defined below. Data and Control packets are defined below.
The CAPWAP Control protocol includes two messages that are never The CAPWAP Control protocol includes two messages that are never
protected by DTLS: the Discovery Request message and the Discovery protected by DTLS: the Discovery Request message and the Discovery
Response message. These messages need to be in the clear to allow Response message. These messages need to be in the clear to allow
the CAPWAP protocol to properly identify and process them. The the CAPWAP protocol to properly identify and process them. The
format of these packets are as follows: format of these packets are as follows:
CAPWAP Control Packet (Discovery Request/Response): CAPWAP Control Packet (Discovery Request/Response):
+-----------------------------------------------------+ +-------------------------------------------+
| IP | UDP | CAPWAP | CAPWAP | Control | Message | | IP | UDP | CAPWAP | Control | Message |
| Hdr | Hdr | Preamble| Header | Header | Element(s) | | Hdr | Hdr | Header | Header | Element(s) |
+-----------------------------------------------------+ +-------------------------------------------+
All other CAPWAP control protocol messages MUST be protected via the All other CAPWAP control protocol messages MUST be protected via the
DTLS protocol, which ensures that the packets are both authenticated DTLS protocol, which ensures that the packets are both authenticated
and encrypted. The format of these packets is as follows: and encrypted. These packets include the CAPWAP DTLS Header, which
is described in Section 4.2. The format of these packets is as
follows:
CAPWAP Control Packet (DTLS Security Required): CAPWAP Control Packet (DTLS Security Required):
+-----------------------------------------------------------------+ +------------------------------------------------------------------+
| IP | UDP | CAPWAP | DTLS | CAPWAP | Control| Message | DTLS | | IP | UDP | CAPWAP | DTLS | CAPWAP | Control| Message | DTLS |
| Hdr | Hdr | Preamble| Hdr | Header | Header | Element(s)| Trlr | | Hdr | Hdr | DTLS Hdr | Hdr | Header | Header | Element(s)| Trlr |
+-----------------------------------------------------------------+ +------------------------------------------------------------------+
\---------- authenticated -----------/ \---------- authenticated -----------/
\------------- encrypted ------------/ \------------- encrypted ------------/
The CAPWAP protocol allows optional protection of data packets, using The CAPWAP protocol allows optional protection of data packets, using
DTLS. Use of data packet protection is determined by AC policy. The DTLS. Use of data packet protection is determined by AC policy.
format of CAPWAP data packets is shown below: When DTLS is utilized, the optional CAPWAP DTLS Header is present,
which is described in Section 4.2. The format of CAPWAP data packets
is shown below:
CAPWAP Plain Text Data Packet : CAPWAP Plain Text Data Packet :
+-----------------------------------------+ +-------------------------------+
| IP | UDP | CAPWAP | CAPWAP | Wireless | | IP | UDP | CAPWAP | Wireless |
| Hdr | Hdr | Preamble| Header | Payload | | Hdr | Hdr | Header | Payload |
+-----------------------------------------+ +-------------------------------+
DTLS Secured CAPWAP Data Packet: DTLS Secured CAPWAP Data Packet:
+-------------------------------------------------------+ +--------------------------------------------------------+
| IP | UDP | CAPWAP | DTLS | CAPWAP | Wireless | DTLS | | IP | UDP | CAPWAP | DTLS | CAPWAP | Wireless | DTLS |
| Hdr | Hdr | Preamble| Hdr | Hdr | Payload | Trlr | | Hdr | Hdr | DTLS Hdr | Hdr | Hdr | Payload | Trlr |
+-------------------------------------------------------+ +--------------------------------------------------------+
\------ authenticated -----/ \------ authenticated -----/
\------- encrypted --------/ \------- encrypted --------/
UDP Header: All CAPWAP packets are encapsulated within UDP. Section UDP Header: All CAPWAP packets are encapsulated within either UDP,
Section 3 defines the specific UDP usage. or UDP-Lite when used over IPv6. Section 3 defines the specific
UDP or UDP-Lite usage.
CAPWAP Preamble: All CAPWAP protocol packets are prefixed with the CAPWAP DTLS Header: All DTLS encrypted CAPWAP protocol packets are
CAPWAP Preamble header, used to identify the frame type that prefixed with the CAPWAP DTLS header (see Section 4.2).
follows. The CAPWAP Preamble header is defined in Section 4.1.
DTLS Header: The DTLS header provides authentication and encrytion DTLS Header: The DTLS header provides authentication and encryption
services to the CAPWAP payload it encapsulates. This protocol is services to the CAPWAP payload it encapsulates. This protocol is
defined in RFC 4347 [9]. defined in RFC 4347 [8].
CAPWAP Header: All CAPWAP protocol packets use a common header that CAPWAP Header: All CAPWAP protocol packets use a common header that
immediately follows the CAPWAP preamble or DTLS header. The immediately follows the CAPWAP preamble or DTLS header. The
CAPWAP Header is defined in Section 4.2. CAPWAP Header is defined in Section 4.3.
Wireless Payload: A CAPWAP protocol packet that contains a wireless Wireless Payload: A CAPWAP protocol packet that contains a wireless
payload is a CAPWAP data packet. The CAPWAP protocol does not payload is a CAPWAP data packet. The CAPWAP protocol does not
specify the format of the wireless payload, which is defined by specify the format of the wireless payload, which is defined by
the appropriate wireless standard. Additional information is in the appropriate wireless standard. Additional information is in
Section 4.3. Section 4.4.
Control Header: The CAPWAP protocol includes a signalling component, Control Header: The CAPWAP protocol includes a signalling component,
known as the CAPWAP control protocol. All CAPWAP control packets known as the CAPWAP control protocol. All CAPWAP control packets
include a Control Header, which is defined in Section 4.4.1. include a Control Header, which is defined in Section 4.5.1.
CAPWAP data packets do not contain a Control Header field. CAPWAP data packets do not contain a Control Header field.
Message Elements: A CAPWAP Control packet includes one or more Message Elements: A CAPWAP Control packet includes one or more
message elements, which are found immediately following the message elements, which are found immediately following the
Control Header. These message elements are in a Type/Length/value Control Header. These message elements are in a Type/Length/value
style header, defined in Section 4.5. style header, defined in Section 4.6.
A CAPWAP implementation MUST be capable of receiving a reassembled A CAPWAP implementation MUST be capable of receiving a reassembled
CAPWAP message of length 4096 bytes. A CAPWAP implementation MAY CAPWAP message of length 4096 bytes. A CAPWAP implementation MAY
indicate that it supports a higher maximum message length, by indicate that it supports a higher maximum message length, by
including the Maximum Message Length message element, see including the Maximum Message Length message element, see
Section 4.5.29 in the Join Request message or the Join Response Section 4.6.29 in the Join Request message or the Join Response
message. message.
4.1. CAPWAP Preamble 4.1. CAPWAP Preamble
The CAPWAP Preamble header is used to identify the payload type that The CAPWAP preamble is common to all CAPWAP transport headers and is
immediately follows, to avoid needing to perform byte comparisons to used to identify the header type that immediately follows. The
determine if the packet is DTLS encrypted or not. The format of the reason for this header is to avoid needing to perform byte
CAPWAP Preamble is as follows: comparisons in order to guess whether the frame is DTLS encrypted or
not. It also provides an extensibility framework that can be used to
support additional transport types. The format of the preamble is as
follows:
0 1 2 3 0
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|Version| Type | Reserved | |Version| Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Version: A 4 bit field which contains the version of CAPWAP used in Version: A 4 bit field which contains the version of CAPWAP used in
this packet. The value for this specification is zero (0). this packet. The value for this specification is zero (0).
Payload Type: A 4 bit field which specifies the payload type that Payload Type: A 4 bit field which specifies the payload type that
follows the preamble header. The following values are supported: follows the UDP header. The following values are supported:
0 - Clear text. If the packet is received on the data UDP port, 0 - CAPWAP Header. The CAPWAP Header (see Section 4.3)
the CAPWAP stack MUST treat the packet as a clear text CAPWAP immediately follows the UDP header. If the packet is received
data packet. If received on the control UDP port, the CAPWAP on the CAPWAP data channel, the CAPWAP stack MUST treat the
stack MUST treat the packet as a clear text CAPWAP control packet as a clear text CAPWAP data packet. If received on the
packet. If the control packet is not a Discovery Request or CAPWAP control channel, the CAPWAP stack MUST treat the packet
Response packet, the packet MUST be dropped. as a clear text CAPWAP control packet. If the control packet
is not a Discovery Request or Discovery Response packet, the
packet MUST be dropped.
1 - DTLS Payload. The packet is a DTLS packet and MAY be a data 1 - CAPWAP DTLS Header. The CAPWAP DTLS Header, and DTLS packet,
or control packet, based on the UDP port it was received on immediately follows the UDP header (see Section 4.2).
(see Section 3).
4.2. CAPWAP DTLS Header
The CAPWAP DTLS Header is used to identify the packet as a DTLS
encrypted packet. The first eight bits includes the common CAPWAP
Preamble. The remaining 24 bits are padding to ensure 4 byte
alignment, and MAY be used in a future version of the protocol. The
DTLS packet [8] always immediately follows this header. The format
of the CAPWAP DTLS Header is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|CAPWAP Preamble| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
CAPWAP Preamble: The CAPWAP Preamble is defined in Section 4.1. The
CAPWAP Preamble's Payload Type field MUST be set to one (1).
Reserved: The 24-bit field is reserved for future use. All Reserved: The 24-bit field is reserved for future use. All
implementations complying with this protocol MUST set to zero any implementations complying with this protocol MUST set to zero any
bits that are reserved in the version of the protocol supported by bits that are reserved in the version of the protocol supported by
that implementation. Receivers MUST ignore all bits not defined that implementation. Receivers MUST ignore all bits not defined
for the version of the protocol they support. for the version of the protocol they support.
4.2. CAPWAP Header 4.3. CAPWAP Header
All CAPWAP protocol messages are encapsulated using a common header All CAPWAP protocol messages are encapsulated using a common header
format, regardless of the CAPWAP control or CAPWAP Data transport format, regardless of the CAPWAP Control or CAPWAP Data transport
used to carry the messages. However, certain flags are not used to carry the messages. However, certain flags are not
applicable for a given transport. Refer to the specific transport applicable for a given transport. Refer to the specific transport
section in order to determine which flags are valid. section in order to determine which flags are valid.
The Version field in the CAPWAP header MUST NOT be modified in any
future CAPWAP specifications unless the Version field in the CAPWAP
Preamble Header is modified. The Version field value is used to
parse the CAPWAP headers.
Note that the optional fields defined in this section MUST be present Note that the optional fields defined in this section MUST be present
in the precise order shown below. in the precise order shown below.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| RID | HLEN | WBID |T|F|L|W|M|K| Flags | |CAPWAP Preamble| HLEN | RID | WBID |T|F|L|W|M|K|Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Fragment ID | Frag Offset |Rsvd | | Fragment ID | Frag Offset |Rsvd |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| (optional) Radio MAC Address | | (optional) Radio MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| (optional) Wireless Specific Information | | (optional) Wireless Specific Information |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Payload .... | | Payload .... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Version: A 4 bit field which contains the version of the CAPWAP CAPWAP Preamble: The CAPWAP Preamble is defined in Section 4.1. The
protocol used in this packet. The value of this field MUST match CAPWAP Preamble's Payload Type field MUST be set to zero (0). If
the version field set in the CAPWAP preamble header (see the CAPWAP DTLS Header is present, the version number in both
Section 4.1). The reason for this duplicate field is to avoid any CAPWAP Preambles MUST match. The reason for this duplicate field
possible tampering of the version field in the preamble header is to avoid any possible tampering of the version field in the
which is not encrypted or authenticated. preamble which is not encrypted or authenticated.
HLEN: A 5 bit field containing the length of the CAPWAP transport
header in 4 byte words (Similar to IP header length). This length
includes the optional headers.
RID: A 5 bit field which contains the Radio ID number for this RID: A 5 bit field which contains the Radio ID number for this
packet. Given that MAC Addresses are not necessarily unique packet. Given that MAC Addresses are not necessarily unique
across physical radios in a WTP, the Radio Identifier (RID) field across physical radios in a WTP, the Radio Identifier (RID) field
is used to indiciate which physical radio the message is is used to indiciate which physical radio the message is
associated with. associated with.
HLEN: A 5 bit field containing the length of the CAPWAP transport
header in 4 byte words (Similar to IP header length). This length
includes the optional headers.
WBID: A 5 bit field which is the wireless binding identifier. The WBID: A 5 bit field which is the wireless binding identifier. The
identifier will indicate the type of wireless packet type identifier will indicate the type of wireless packet type
associated with the radio. The following values are defined: associated with the radio. The following values are defined:
1 - IEEE 802.11 1 - IEEE 802.11
2 - IEEE 802.16 2 - IEEE 802.16
3 - EPCGlobal 3 - EPCGlobal
T: The Type 'T' bit indicates the format of the frame being T: The Type 'T' bit indicates the format of the frame being
transported in the payload. When this bit is set to one (1), the transported in the payload. When this bit is set to one (1), the
payload has the native frame format indicated by the WBID field. payload has the native frame format indicated by the WBID field.
When this bit is zero (0) the payload is an IEEE 802.3 frame. When this bit is zero (0) the payload is an IEEE 802.3 frame.
F: The Fragment 'F' bit indicates whether this packet is a fragment. F: The Fragment 'F' bit indicates whether this packet is a fragment.
skipping to change at page 44, line 30 skipping to change at page 42, line 49
converted to 802.3 by the WTP. This field is only present if the converted to 802.3 by the WTP. This field is only present if the
'M' bit is set. The HLEN field assumes 4 byte alignment, and this 'M' bit is set. The HLEN field assumes 4 byte alignment, and this
field MUST be padded with zeroes (0x00) if it is not 4 byte field MUST be padded with zeroes (0x00) if it is not 4 byte
aligned. aligned.
The field contains the basic format: The field contains the basic format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | MAC Address | Length | MAC Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Length: The length of the MAC Address field [18] [19].
Type: The format of the MAC Address field. The following values
are supported:
1 - MAC-48 or EUI-48 [18], which is a 48 bit MAC Address.
2 - EUI-64 [19] which is a 64 bit MAC Address.
MAC Address: The MAC Address of the receiving radio. MAC Address: The MAC Address of the receiving radio.
Wireless Specific Information: This optional field contains Wireless Specific Information: This optional field contains
technology specific information that may be used to carry per technology specific information that may be used to carry per
packet wireless information. This field is only present if the packet wireless information. This field is only present if the
'W' bit is set. The HLEN field assumes 4 byte alignment, and this 'W' bit is set. The HLEN field assumes 4 byte alignment, and this
field MUST be padded with zeroes (0x00) if it is not 4 byte field MUST be padded with zeroes (0x00) if it is not 4 byte
aligned. aligned.
skipping to change at page 45, line 29 skipping to change at page 43, line 41
Length: The length of the data field Length: The length of the data field
Data: Wireless specific information, defined by the wireless Data: Wireless specific information, defined by the wireless
specific binding. specific binding.
Payload: This field contains the header for a CAPWAP Data Message or Payload: This field contains the header for a CAPWAP Data Message or
CAPWAP Control Message, followed by the data contained in the CAPWAP Control Message, followed by the data contained in the
message. message.
4.3. CAPWAP Data Messages 4.4. CAPWAP Data Messages
There are two different types of CAPWAP data packets, CAPWAP Data There are two different types of CAPWAP data packets, CAPWAP Data
Channel Keep Alive packets and Data Payload packets. The first is Channel Keep Alive packets and Data Payload packets. The first is
used by the WTP to synchronize the control and data channels, and to used by the WTP to synchronize the control and data channels, and to
maintain freshness of the data channel. The second is used to maintain freshness of the data channel. The second is used to
transmit user payloads between the AC and WTP. This section transmit user payloads between the AC and WTP. This section
describes both types of CAPWAP data packet formats. describes both types of CAPWAP data packet formats.
Both CAPWAP data messages are transmitted on the data channel UDP Both CAPWAP data messages are transmitted on the CAPWAP data channel.
port.
4.3.1. CAPWAP Data Keepalive 4.4.1. CAPWAP Data Keepalive
The CAPWAP Data Channel Keep Alive packet is used to bind the CAPWAP The CAPWAP Data Channel Keep Alive packet is used to bind the CAPWAP
control channel with the data channel, and to maintain freshness of control channel with the data channel, and to maintain freshness of
the data channel, ensuring that the channel is still functioning. the data channel, ensuring that the channel is still functioning.
The CAPWAP Data Channel Keep Alive packet is transmitted by the WTP The CAPWAP Data Channel Keep Alive packet is transmitted by the WTP
when the DataChannelKeepAlive timer expires. When the CAPWAP Data when the DataChannelKeepAlive timer expires. When the CAPWAP Data
Channel Keep Alive packet is transmitted, the WTP sets the Channel Keep Alive packet is transmitted, the WTP sets the
DataChannelDeadInterval timer. DataChannelDeadInterval timer.
In the CAPWAP Data Channel Keep Alive packet, all of the fields in In the CAPWAP Data Channel Keep Alive packet, all of the fields in
skipping to change at page 46, line 18 skipping to change at page 44, line 31
Upon receiving a CAPWAP Data Channel Keep Alive packet, the WTP Upon receiving a CAPWAP Data Channel Keep Alive packet, the WTP
cancels the DataChannelDeadInterval timer and resets the cancels the DataChannelDeadInterval timer and resets the
DataChannelKeepAlive timer. The CAPWAP Data Channel Keep Alive DataChannelKeepAlive timer. The CAPWAP Data Channel Keep Alive
packet is retransmitted by the WTP in the same manner as the CAPWAP packet is retransmitted by the WTP in the same manner as the CAPWAP
control messages. If the DataChannelDeadInterval timer expires, the control messages. If the DataChannelDeadInterval timer expires, the
WTP tears down the control DTLS session, and the data DTLS session if WTP tears down the control DTLS session, and the data DTLS session if
one existed. one existed.
The CAPWAP Data Channel Keep Alive packet contains the following The CAPWAP Data Channel Keep Alive packet contains the following
payload immediately following the CAPWAP Header (see Section 4.2) payload immediately following the CAPWAP Header (see Section 4.3)
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Element Length | Message Element [0..N] ... | Message Element Length | Message Element [0..N] ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message Element Length: The Length field indicates the number of Message Element Length: The Length field indicates the number of
bytes following the CAPWAP Header. bytes following the CAPWAP Header.
Message Element[0..N]: The message element(s) carry the information Message Element[0..N]: The message element(s) carry the information
pertinent to each of the CAPWAP Data Keepalive message. The pertinent to each of the CAPWAP Data Keepalive message. The
following message elements MUST be present in this CAPWAP message: following message elements MUST be present in this CAPWAP message:
Session ID, see Section 4.5.35 Session ID, see Section 4.6.35
4.3.2. Data Payload 4.4.2. Data Payload
A CAPWAP protocol Data Payload packet encapsulates a forwarded A CAPWAP protocol Data Payload packet encapsulates a forwarded
wireless frame. The CAPWAP protocol defines two different modes of wireless frame. The CAPWAP protocol defines two different modes of
encapsulation; IEEE 802.3 and native wireless. IEEE 802.3 encapsulation; IEEE 802.3 and native wireless. IEEE 802.3
encapsulation requires that the bridging function be performed in the encapsulation requires that the bridging function be performed in the
WTP. An IEEE 802.3 encapsulated user payload frame has the following WTP. An IEEE 802.3 encapsulated user payload frame has the following
format: format:
+------------------------------------------------------+ +------------------------------------------------------+
| IP Header | UDP Header | CAPWAP Header | 802.3 Frame | | IP Header | UDP Header | CAPWAP Header | 802.3 Frame |
skipping to change at page 47, line 11 skipping to change at page 45, line 23
mode. The format of the encapsulated CAPWAP data frame is subject to mode. The format of the encapsulated CAPWAP data frame is subject to
the rules defined by the specific wireless technology binding. Each the rules defined by the specific wireless technology binding. Each
wireless technology binding MUST contain a section entitled "Payload wireless technology binding MUST contain a section entitled "Payload
Encapsulation", which defines the format of the wireless payload that Encapsulation", which defines the format of the wireless payload that
is encapsulated within CAPWAP Data packets. is encapsulated within CAPWAP Data packets.
If the encapsulated frame would exceed the transport layer's MTU, the If the encapsulated frame would exceed the transport layer's MTU, the
sender is responsible for fragmentation of the frame, as specified in sender is responsible for fragmentation of the frame, as specified in
Section 3.4. Section 3.4.
4.3.3. Establishment of a DTLS Data Channel 4.4.3. Establishment of a DTLS Data Channel
If the AC and WTP are configured to tunnel the data channel over If the AC and WTP are configured to tunnel the data channel over
DTLS, the proper DTLS session must be initiated. To avoid having to DTLS, the proper DTLS session must be initiated. To avoid having to
reauthenticate and reauthorize an AC and WTP, the DTLS data channel reauthenticate and reauthorize an AC and WTP, the DTLS data channel
MUST be initiated using the TLS session resumption feature [11]. MUST be initiated using the TLS session resumption feature [7].
When establishing the DTLS-encrypted data channel, the WTP MUST When establishing the DTLS-encrypted data channel, the WTP MUST
provide the identifier returned during the initialization of the provide the identifier returned during the initialization of the
control channel to the DTLS component so it can perform the control channel to the DTLS component so it can perform the
resumption using the proper session information. resumption using the proper session information.
The AC DTLS implementation MUST NOT accept a session resumption The AC DTLS implementation MUST NOT accept a session resumption
request for a DTLS session in which the control channel for the request for a DTLS session in which the control channel for the
session has been torn down. session has been torn down.
4.4. CAPWAP Control Messages 4.5. CAPWAP Control Messages
The CAPWAP Control protocol provides a control channel between the The CAPWAP Control protocol provides a control channel between the
WTP and the AC. Control messages are divided into the following WTP and the AC. Control messages are divided into the following
message types: message types:
Discovery: CAPWAP Discovery messages are used to identify potential Discovery: CAPWAP Discovery messages are used to identify potential
ACs, their load and capabilities. ACs, their load and capabilities.
Join: CAPWAP Join messages are used by a WTP to request service from Join: CAPWAP Join messages are used by a WTP to request service from
an AC, and for the AC to respond to the WTP. an AC, and for the AC to respond to the WTP.
skipping to change at page 48, line 24 skipping to change at page 46, line 35
Management and Station Session Management CAPWAP control messages Management and Station Session Management CAPWAP control messages
MUST be implemented. Device Management Operations messages MAY be MUST be implemented. Device Management Operations messages MAY be
implemented. implemented.
CAPWAP control messages sent from the WTP to the AC indicate that the CAPWAP control messages sent from the WTP to the AC indicate that the
WTP is operational, providing an implicit keep-alive mechanism for WTP is operational, providing an implicit keep-alive mechanism for
the WTP. The Control Channel Management Echo Request and Echo the WTP. The Control Channel Management Echo Request and Echo
Response messages provide an explicit keep-alive mechanism when other Response messages provide an explicit keep-alive mechanism when other
CAPWAP control messages are not exchanged. CAPWAP control messages are not exchanged.
4.4.1. Control Message Format 4.5.1. Control Message Format
All CAPWAP control messages are sent encapsulated within the CAPWAP All CAPWAP control messages are sent encapsulated within the CAPWAP
header (see Section 4.2). Immediately following the CAPWAP header, header (see Section 4.3). Immediately following the CAPWAP header,
is the control header, which has the following format: is the control header, which has the following format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Type | | Message Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Seq Num | Msg Element Length | Flags | | Seq Num | Msg Element Length | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Msg Element [0..N] ... | Msg Element [0..N] ...
+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+
4.4.1.1. Message Type 4.5.1.1. Message Type
The Message Type field identifies the function of the CAPWAP control The Message Type field identifies the function of the CAPWAP control
message. The Message Type field is comprised of an IANA Enterprise message. The Message Type field is comprised of an IANA Enterprise
Number and an enterprise specific message type number. The first Number and an enterprise specific message type number. The first
three octets contain the enterprise number in network byte order, three octets contain the enterprise number in network byte order,
with zero used for CAPWAP protocol defined message types and the IEEE with zero used for CAPWAP protocol defined message types and the IEEE
802.11 IANA assigned enterprise number 13277 is used for IEEE 802.11 802.11 IANA assigned enterprise number 13277 is used for IEEE 802.11
technology specific message types. The last octet is the enterprise technology specific message types. The last octet is the enterprise
specific message type number, which has a range from 0 to 255. specific message type number, which has a range from 0 to 255.
The message type field is defined as: The message type field is defined as:
Message Type = IANA Enterprise Number * 256 + Enterprise Specific Message Type Number Message Type =
IANA Enterprise Number * 256 +
Enterprise Specific Message Type Number
The CAPWAP protocol reliability mechanism requires that messages be The CAPWAP protocol reliability mechanism requires that messages be
defined in pairs, consisting of both a Request and a Response defined in pairs, consisting of both a Request and a Response
message. The Response message MUST acknowledge the Request message. message. The Response message MUST acknowledge the Request message.
The assignment of CAPWAP control Message Type Values always occurs in The assignment of CAPWAP control Message Type Values always occurs in
pairs. All Request messages have odd numbered Message Type Values, pairs. All Request messages have odd numbered Message Type Values,
and all Response messages have even numbered Message Type Values. and all Response messages have even numbered Message Type Values.
The Request value MUST be assigned first. As an example, assigning a The Request value MUST be assigned first. As an example, assigning a
Message Type Value of 3 for a Request message and 4 for a Response Message Type Value of 3 for a Request message and 4 for a Response
message is valid, while assigning a Message Type Value of 4 for a message is valid, while assigning a Message Type Value of 4 for a
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Reset Response 18 Reset Response 18
Primary Discovery Request 19 Primary Discovery Request 19
Primary Discovery Response 20 Primary Discovery Response 20
Data Transfer Request 21 Data Transfer Request 21
Data Transfer Response 22 Data Transfer Response 22
Clear Configuration Request 23 Clear Configuration Request 23
Clear Configuration Response 24 Clear Configuration Response 24
Station Configuration Request 25 Station Configuration Request 25
Station Configuration Response 26 Station Configuration Response 26
4.4.1.2. Sequence Number 4.5.1.2. Sequence Number
The Sequence Number Field is an identifier value used to match The Sequence Number Field is an identifier value used to match
Request and Response packets. When a CAPWAP packet with a Request Request and Response packets. When a CAPWAP packet with a Request
Message Type Value is received, the value of the Sequence Number Message Type Value is received, the value of the Sequence Number
field is copied into the corresponding Response message. field is copied into the corresponding Response message.
When a CAPWAP control message is sent, the sender's internal sequence When a CAPWAP control message is sent, the sender's internal sequence
number counter is monotonically incremented, ensuring that no two number counter is monotonically incremented, ensuring that no two
pending Request messages have the same Sequence Number. The Sequence pending Request messages have the same Sequence Number. The Sequence
Number field wraps back to zero. Number field wraps back to zero.
4.4.1.3. Message Element Length 4.5.1.3. Message Element Length
The Length field indicates the number of bytes following the Sequence The Length field indicates the number of bytes following the Sequence
Number field. Number field.
4.4.1.4. Flags 4.5.1.4. Flags
The Flags field MUST be set to zero. The Flags field MUST be set to zero.
4.4.1.5. Message Element[0..N] 4.5.1.5. Message Element[0..N]
The message element(s) carry the information pertinent to each of the The message element(s) carry the information pertinent to each of the
control message types. Every control message in this specification control message types. Every control message in this specification
specifies which message elements are permitted. specifies which message elements are permitted.
When a WTP or AC receives a CAPWAP message without a message element When a WTP or AC receives a CAPWAP message without a message element
that is specified as mandatory for the CAPWAP message, then the that is specified as mandatory for the CAPWAP message, then the
CAPWAP message is discarded. If the received message was a Request CAPWAP message is discarded. If the received message was a Request
message for which the corresponding Response message carries message message for which the corresponding Response message carries message
elements, then a corresponding Response message with a Result Code elements, then a corresponding Response message with a Result Code
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When a WTP or AC receives a CAPWAP message with a message element When a WTP or AC receives a CAPWAP message with a message element
that the WTP or AC does not recognize, the CAPWAP message is that the WTP or AC does not recognize, the CAPWAP message is
discarded. If the received message was a Request message for which discarded. If the received message was a Request message for which
the corresponding Response message carries message elements, then a the corresponding Response message carries message elements, then a
corresponding Response message with a Result Code message element corresponding Response message with a Result Code message element
indicating "Failure - Unrecognized Message Element" and one or more indicating "Failure - Unrecognized Message Element" and one or more
Returned Message Element message elements is included, containing the Returned Message Element message elements is included, containing the
unrecognized message element(s). unrecognized message element(s).
4.4.2. Control Message Quality of Service 4.5.2. Control Message Quality of Service
It is recommended that CAPWAP control messages be sent by both the AC It is recommended that CAPWAP control messages be sent by both the AC
and the WTP with an appropriate Quality of Service precedence value, and the WTP with an appropriate Quality of Service precedence value,
ensuring that congestion in the network minimizes occurrences of ensuring that congestion in the network minimizes occurrences of
CAPWAP control channel disconnects. Therefore, a Quality of Service CAPWAP control channel disconnects. Therefore, a Quality of Service
enabled CAPWAP device SHOULD use the following values: enabled CAPWAP device SHOULD use the following values:
802.1P: The precedence value of 7 SHOULD be used. 802.1P: The precedence value of 7 SHOULD be used.
DSCP: The DSCP tag value of 46 SHOULD be used. DSCP: The DSCP tag value of 46 SHOULD be used.
4.4.3. Retransmissions 4.5.3. Retransmissions
The CAPWAP control protocol operates as a reliable transport. For The CAPWAP control protocol operates as a reliable transport. For
each Request message, a Response message is defined, which is used to each Request message, a Response message is defined, which is used to
acknowledge receipt of the Request message. In addition, the control acknowledge receipt of the Request message. In addition, the control
header Sequence Number field is used to pair the Request and Response header Sequence Number field is used to pair the Request and Response
messages (see Section 4.4.1). messages (see Section 4.5.1).
Response messages are not explicitly acknowledged, therefore if a Response messages are not explicitly acknowledged, therefore if a
Response message is not received, the original Request message is Response message is not received, the original Request message is
retransmitted. Implementations MAY cache Response messages to retransmitted. Implementations MAY cache Response messages to
respond to a retransmitted Request messages with minimal local respond to a retransmitted Request messages with minimal local
processing. Retransmitted Request messages MUST NOT be altered by processing. Retransmitted Request messages MUST NOT be altered by
the sender. The sender MUST assume that the original Request message the sender. The sender MUST assume that the original Request message
was processed, but that the Response message was lost. Any was processed, but that the Response message was lost. Any
alterations to the original Request message MUST have a new Sequence alterations to the original Request message MUST have a new Sequence
Number, and be treated as a new Request message by the receiver. Number, and be treated as a new Request message by the receiver.
After transmitting a Request message, the RetransmitInterval (see After transmitting a Request message, the RetransmitInterval (see
Section 4.6) timer and MaxRetransmit (see Section 4.7) variable are Section 4.7) timer and MaxRetransmit (see Section 4.8) variable are
used to determine if the original Request message needs to be used to determine if the original Request message needs to be
retransmitted. The RetransmitInterval timer is used the first time retransmitted. The RetransmitInterval timer is used the first time
the Request is retransmitted. The timer is then doubled every the Request is retransmitted. The timer is then doubled every
subsequent time the same Request message is retransmitted, up to subsequent time the same Request message is retransmitted, up to
MaxRetransmit but no more than half the EchoInterval timer (see MaxRetransmit but no more than half the EchoInterval timer (see
Section 4.6.5). Response messages are not subject to these timers. Section 4.7.5). Response messages are not subject to these timers.
When a Request message is retransmitted, it MUST be re-encrypted via When a Request message is retransmitted, it MUST be re-encrypted via
the DTLS stack. If the peer had received the Request message, and the DTLS stack. If the peer had received the Request message, and
the corresponding Response message was lost, it is necessary to the corresponding Response message was lost, it is necessary to
ensure that retransmitted Request messages are not identified as ensure that retransmitted Request messages are not identified as
replays by the DTLS stack. Similarly, any cached Response messages replays by the DTLS stack. Similarly, any cached Response messages
that are retransmitted as a result of receiving a retransmitted that are retransmitted as a result of receiving a retransmitted
Request message MUST be re-encrypted via DTLS. Request message MUST be re-encrypted via DTLS.
Duplicate Response messages, identified by the Sequence Number field Duplicate Response messages, identified by the Sequence Number field
in the CAPWAP control message header, SHOULD be discarded upon in the CAPWAP control message header, SHOULD be discarded upon
receipt. receipt.
4.5. CAPWAP Protocol Message Elements 4.6. CAPWAP Protocol Message Elements
This section defines the CAPWAP Protocol message elements which are This section defines the CAPWAP Protocol message elements which are
included in CAPWAP protocol control messages. included in CAPWAP protocol control messages.
Message elements are used to carry information needed in control Message elements are used to carry information needed in control
messages. Every message element is identified by the Type Value messages. Every message element is identified by the Type Value
field, defined below. The total length of the message elements is field, defined below. The total length of the message elements is
indicated in the message element Length field. indicated in the message element Length field.
All of the message element definitions in this document use a diagram All of the message element definitions in this document use a diagram
similar to the one below in order to depict its format. Note that to similar to the one below in order to depict its format. Note that to
simplify this specification, these diagrams do not include the header simplify this specification, these diagrams do not include the header
fields (Type and Length). The header field values are defined in the fields (Type and Length). The header field values are defined in the
message element descriptions. message element descriptions.
Unless otherwise specified, a control message that lists a set of Unless otherwise specified, a control message that lists a set of
supported (or expected) message elements MUST not expect the message supported (or expected) message elements MUST not expect the message
elements to be in any specific order. The sender may include the elements to be in any specific order. The sender MAY include the
message elements in any order. Unless otherwise noted, one message message elements in any order. Unless otherwise noted, one message
element of each type is present in a given control message. element of each type is present in a given control message.
Additional message elements may be defined in separate IETF Additional message elements may be defined in separate IETF
documents. documents.
The format of a message element uses the TLV format shown here: The format of a message element uses the TLV format shown here:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
skipping to change at page 54, line 32 skipping to change at page 52, line 32
Result Code 33 Result Code 33
Returned Message Element 34 Returned Message Element 34
Session ID 35 Session ID 35
Statistics Timer 36 Statistics Timer 36
Vendor Specific Payload 37 Vendor Specific Payload 37
WTP Board Data 38 WTP Board Data 38
WTP Descriptor 39 WTP Descriptor 39
WTP Fallback 40 WTP Fallback 40
WTP Frame Tunnel Mode 41 WTP Frame Tunnel Mode 41
WTP IPv4 IP Address 42 WTP IPv4 IP Address 42
WTP MAC Type 43 WTP IPv6 IP Address 43
WTP Name 44 WTP MAC Type 44
WTP Operational Statistics 45 WTP Name 45
WTP Radio Statistics 46 WTP Operational Statistics 46
WTP Reboot Statistics 47 WTP Radio Statistics 47
WTP Static IP Address Information 48 WTP Reboot Statistics 48
WTP Static IP Address Information 49
4.5.1. AC Descriptor 4.6.1. AC Descriptor
The AC Descriptor message element is used by the AC to communicate The AC Descriptor message element is used by the AC to communicate
its current state. The value contains the following fields. its current state. The value contains the following fields.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Stations | Limit | | Stations | Limit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Active WTPs | Max WTPs | | Active WTPs | Max WTPs |
skipping to change at page 55, line 48 skipping to change at page 53, line 48
Security: A 8 bit bit mask specifying the authentication credential Security: A 8 bit bit mask specifying the authentication credential
type supported by the AC. The following values are supported (see type supported by the AC. The following values are supported (see
Section 2.4.4): Section 2.4.4):
1 - X.509 Certificate Based 1 - X.509 Certificate Based
2 - Pre-Shared Secret 2 - Pre-Shared Secret
R-MAC Field: The AC supports the optional Radio MAC Address field R-MAC Field: The AC supports the optional Radio MAC Address field
in the CAPWAP transport Header (see Section 4.2). in the CAPWAP transport Header (see Section 4.3).
Reserved: A set of reserved bits for future use. All Reserved: A set of reserved bits for future use. All
implementations complying with this protocol MUST set to zero any implementations complying with this protocol MUST set to zero any
bits that are reserved in the version of the protocol supported by bits that are reserved in the version of the protocol supported by
that implementation. Receivers MUST ignore all bits not defined that implementation. Receivers MUST ignore all bits not defined
for the version of the protocol they support. for the version of the protocol they support.
DTLS Policy: The AC communicates its policy on the use of DTLS for DTLS Policy: The AC communicates its policy on the use of DTLS for
the CAPWAP data channel. The AC MAY communicate more than one the CAPWAP data channel. The AC MAY communicate more than one
supported option, represented by the bit field below. The WTP supported option, represented by the bit field below. The WTP
skipping to change at page 56, line 37 skipping to change at page 54, line 37
4 - Hardware Version: The AC's hardware version number. 4 - Hardware Version: The AC's hardware version number.
5 - Software Version: The AC's Software (firmware) version 5 - Software Version: The AC's Software (firmware) version
number. number.
Length: Length of vendor specific encoding of AC information. Length: Length of vendor specific encoding of AC information.
Value: Vendor specific encoding of AC information. Value: Vendor specific encoding of AC information.
4.5.2. AC IPv4 List 4.6.2. AC IPv4 List
The AC IPv4 List message element is used to configure a WTP with the The AC IPv4 List message element is used to configure a WTP with the
latest list of ACs available for the WTP to join. latest list of ACs available for the WTP to join.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AC IP Address[] | | AC IP Address[] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 2 for AC IPv4 List Type: 2 for AC IPv4 List
Length: >= 4 Length: >= 4
The AC IP Address: An array of 32-bit integers containing AC IPv4 The AC IP Address: An array of 32-bit integers containing AC IPv4
Addresses. Addresses.
4.5.3. AC IPv6 List 4.6.3. AC IPv6 List
The AC IPv6 List message element is used to configure a WTP with the The AC IPv6 List message element is used to configure a WTP with the
latest list of ACs available for the WTP to join. latest list of ACs available for the WTP to join.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AC IP Address[] | | AC IP Address[] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AC IP Address[] | | AC IP Address[] |
skipping to change at page 57, line 35 skipping to change at page 55, line 35
| AC IP Address[] | | AC IP Address[] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 3 for AC IPV6 List Type: 3 for AC IPV6 List
Length: >= 16 Length: >= 16
The AC IP Address: An array of 128-bit integers containing AC IPv6 The AC IP Address: An array of 128-bit integers containing AC IPv6
Addresses. Addresses.
4.5.4. AC Name 4.6.4. AC Name
The AC Name message element contains an UTF-8 representation of the The AC Name message element contains an UTF-8 representation of the
AC identity. The value is a variable length byte string. The string AC identity. The value is a variable length byte string. The string
is NOT zero terminated. is NOT zero terminated.
0 0
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Name ... | Name ...
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Type: 4 for AC Name Type: 4 for AC Name
Length: > 0 Length: > 0
Name: A variable length UTF-8 encoded string containing the AC's Name: A variable length UTF-8 encoded string containing the AC's
name name
4.5.5. AC Name with Index 4.6.5. AC Name with Index
The AC Name with Index message element is sent by the AC to the WTP The AC Name with Index message element is sent by the AC to the WTP
to configure preferred ACs. The number of instances of this message to configure preferred ACs. The number of instances of this message
element is equal to the number of ACs configured on the WTP. element is equal to the number of ACs configured on the WTP.
0 1 0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Index | AC Name... | Index | AC Name...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 5 for AC Name with Index Type: 5 for AC Name with Index
Length: > 2 Length: > 2
Index: The index of the preferred server (1=primary, 2=secondary). Index: The index of the preferred server (1=primary, 2=secondary).
AC Name: A variable length UTF-8 encoded string containing the AC AC Name: A variable length UTF-8 encoded string containing the AC
name. name.
4.5.6. AC Timestamp 4.6.6. AC Timestamp
The AC Timestamp message element is sent by the AC to synchronize the The AC Timestamp message element is sent by the AC to synchronize the
WTP clock. WTP clock.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp | | Timestamp |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 6 for AC Timestamp Type: 6 for AC Timestamp
Length: 4 Length: 4
Timestamp: The AC's current time, allowing all of the WTPs to be Timestamp: The AC's current time, allowing all of the WTPs to be
time synchronized in the format defined by Network Time Protocol time synchronized in the format defined by Network Time Protocol
(NTP) in RFC 1305 [3]. (NTP) in RFC 1305 [3].
4.5.7. Add MAC ACL Entry 4.6.7. Add MAC ACL Entry
The Add MAC Access Control List (ACL) Entry message element is used The Add MAC Access Control List (ACL) Entry message element is used
by an AC to add a MAC ACL list entry on a WTP, ensuring that the WTP by an AC to add a MAC ACL list entry on a WTP, ensuring that the WTP
no longer provides service to the MAC addresses provided in the no longer provides service to the MAC addresses provided in the
message. The MAC Addresses provided in this message element are not message. The MAC Addresses provided in this message element are not
expected to be saved in non-volatile memory on the WTP. expected to be saved in non-volatile memory on the WTP.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Num of Entries| Type | MAC Address ... | Num of Entries| Length | MAC Address ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 7 for Add MAC ACL Entry Type: 7 for Add MAC ACL Entry
Length: >= 8 Length: >= 8
Num of Entries: The number of instances of the Type/MAC Addresses Num of Entries: The number of instances of the Type/MAC Addresses
fields in the array. fields in the array.
Type: The format of the following MAC Address field. One of the Length: The length of the MAC Address field.
following values are supported:
1 - MAC-48 or EUI-48 [18], which is a 48 bit MAC Address.
2 - EUI-64 [19] which is a 64 bit MAC Address.
MAC Address: MAC Addresses to add to the ACL. MAC Address: MAC Addresses to add to the ACL.
4.5.8. Add Station 4.6.8. Add Station
The Add Station message element is used by the AC to inform a WTP The Add Station message element is used by the AC to inform a WTP
that it should forward traffic for a station. The Add Station that it should forward traffic for a station. The Add Station
message element is accompanied by technology specific binding message element is accompanied by technology specific binding
information element(s) which may include security parameters. information element(s) which may include security parameters.
Consequently, the security parameters must be applied by the WTP for Consequently, the security parameters MUST be applied by the WTP for
the station. the station.
After station policy has been delivered to the WTP through the Add After station policy has been delivered to the WTP through the Add
Station message element, an AC may change any policies by sending a Station message element, an AC MAY change any policies by sending a
modified Add Station message element. When a WTP receives an Add modified Add Station message element. When a WTP receives an Add
Station message element for an existing station, it MUST override any Station message element for an existing station, it MUST override any
existing state for the station. existing state for the station.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Radio ID | Type | MAC Address ... | Radio ID | Length | MAC Address ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VLAN Name... | VLAN Name...
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Type: 8 for Add Station Type: 8 for Add Station
Length: >= 8 Length: >= 8
Radio ID: An 8-bit value representing the radio Radio ID: An 8-bit value representing the radio
Type: The format of the following MAC Address field. One of the Length: The length of the MAC Address field.
following values are supported:
1 - MAC-48 or EUI-48 [18], which is a 48 bit MAC Address.
2 - EUI-64 [19] which is a 64 bit MAC Address.
MAC Address: The station's MAC Address MAC Address: The station's MAC Address
VLAN Name: An optional variable length UTF-8 encoded string VLAN Name: An optional variable length UTF-8 encoded string
containing the VLAN Name on which the WTP is to locally bridge containing the VLAN Name on which the WTP is to locally bridge
user data. Note this field is only valid with WTPs configured in user data. Note this field is only valid with WTPs configured in
Local MAC mode. Local MAC mode.
4.5.9. Add Static MAC ACL Entry 4.6.9. Add Static MAC ACL Entry
The Add Static MAC ACL Entry message element is used by an AC to add The Add Static MAC ACL Entry message element is used by an AC to add
a permanent ACL entry on a WTP, ensuring that the WTP no longer a permanent ACL entry on a WTP, ensuring that the WTP no longer
provides any service to the MAC addresses provided in the message. provides any service to the MAC addresses provided in the message.
The MAC Addresses provided in this message element are expected to be The MAC Addresses provided in this message element are expected to be
saved in non-volative memory on the WTP. saved in non-volative memory on the WTP.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Num of Entries| Type | MAC Address ... | Num of Entries| Length | MAC Address ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 9 for Add Static MAC ACL Entry Type: 9 for Add Static MAC ACL Entry
Length: >= 8 Length: >= 8
Num of Entries: The number of instances of the Type/MAC Addresses Num of Entries: The number of instances of the Type/MAC Addresses
fields in the array. fields in the array.
Type: The format of the following MAC Address field. One of the Length: The length of the MAC Address field.
following values are supported:
1 - MAC-48 or EUI-48 [18], which is a 48 bit MAC Address.
2 - EUI-64 [19] which is a 64 bit MAC Address.
MAC Address: MAC Addresses to add to the permanent ACL. MAC Address: MAC Addresses to add to the permanent ACL.
4.5.10. CAPWAP Control IPv4 Address 4.6.10. CAPWAP Control IPv4 Address
The CAPWAP Control IPv4 Address message element is sent by the AC to The CAPWAP Control IPv4 Address message element is sent by the AC to
the WTP during the discovery process and is used by the AC to provide the WTP during the discovery process and is used by the AC to provide
the interfaces available on the AC, and the current number of WTPs the interfaces available on the AC, and the current number of WTPs
connected. When multiple CAPWAP Control IPV4 Address message connected. When multiple CAPWAP Control IPV4 Address message
elements are returned, the WTP SHOULD perform load balancing across elements are returned, the WTP SHOULD perform load balancing across
the multiple interfaces. the multiple interfaces.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
skipping to change at page 61, line 41 skipping to change at page 59, line 21
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 10 for CAPWAP Control IPv4 Address Type: 10 for CAPWAP Control IPv4 Address
Length: 6 Length: 6
IP Address: The IP Address of an interface. IP Address: The IP Address of an interface.
WTP Count: The number of WTPs currently connected to the interface. WTP Count: The number of WTPs currently connected to the interface.
4.5.11. CAPWAP Control IPv6 Address 4.6.11. CAPWAP Control IPv6 Address
The CAPWAP Control IPv6 Address message element is sent by the AC to The CAPWAP Control IPv6 Address message element is sent by the AC to
the WTP during the discovery process and is used by the AC to provide the WTP during the discovery process and is used by the AC to provide
the interfaces available on the AC, and the current number of WTPs the interfaces available on the AC, and the current number of WTPs
connected. This message element is useful for the WTP to perform connected. This message element is useful for the WTP to perform
load balancing across multiple interfaces. load balancing across multiple interfaces.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 62, line 27 skipping to change at page 60, line 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 11 for CAPWAP Control IPv6 Address Type: 11 for CAPWAP Control IPv6 Address
Length: 18 Length: 18
IP Address: The IP Address of an interface. IP Address: The IP Address of an interface.
WTP Count: The number of WTPs currently connected to the interface. WTP Count: The number of WTPs currently connected to the interface.
4.5.12. CAPWAP Timers 4.6.12. CAPWAP Timers
The CAPWAP Timers message element is used by an AC to configure The CAPWAP Timers message element is used by an AC to configure
CAPWAP timers on a WTP. CAPWAP timers on a WTP.
0 1 0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Discovery | Echo Request | | Discovery | Echo Request |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 12 for CAPWAP Timers Type: 12 for CAPWAP Timers
Length: 2 Length: 2
Discovery: The number of seconds between CAPWAP Discovery messages, Discovery: The number of seconds between CAPWAP Discovery messages,
when the WTP is in the discovery phase. when the WTP is in the discovery phase.
Echo Request: The number of seconds between WTP Echo Request CAPWAP Echo Request: The number of seconds between WTP Echo Request CAPWAP
messages. The default value for this message element is specified messages. The default value for this message element is specified
in Section 4.6.5. in Section 4.7.5.
4.5.13. Data Transfer Data 4.6.13. Data Transfer Data
The Data Transfer Data message element is used by the WTP to provide The Data Transfer Data message element is used by the WTP to provide
information to the AC for debugging purposes. information to the AC for debugging purposes.
0 1 2 0 1 2
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Type | Data Length | Data .... | Data Type | Data Length | Data ....
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 63, line 26 skipping to change at page 61, line 4
Type: 13 for Data Transfer Data Type: 13 for Data Transfer Data
Length: >= 3 Length: >= 3
Data Type: An 8-bit value the type of information being sent. The Data Type: An 8-bit value the type of information being sent. The
following values are supported: following values are supported:
1 - WTP Crash Data 1 - WTP Crash Data
2 - WTP Memory Dump 2 - WTP Memory Dump
Data Length: Length of data field. Data Length: Length of data field.
Data: Debug information. Data: Debug information.
4.5.14. Data Transfer Mode 4.6.14. Data Transfer Mode
The Data Transfer Mode message element is used by the WTP to indicate The Data Transfer Mode message element is used by the WTP to indicate
the type of data transfer information it is sending to the AC for the type of data transfer information it is sending to the AC for
debugging purposes. debugging purposes.
0 0
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Data Type | | Data Type |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
skipping to change at page 64, line 9 skipping to change at page 61, line 31
Length: 1 Length: 1
Data Type: An 8-bit value the type of information being requested. Data Type: An 8-bit value the type of information being requested.
The following values are supported: The following values are supported:
1 - WTP Crash Data 1 - WTP Crash Data
2 - WTP Memory Dump 2 - WTP Memory Dump
4.5.15. Decryption Error Report 4.6.15. Decryption Error Report
The Decryption Error Report message element value is used by the WTP The Decryption Error Report message element value is used by the WTP
to inform the AC of decryption errors that have occurred since the to inform the AC of decryption errors that have occurred since the
last report. Note that this error reporting mechanism is not used if last report. Note that this error reporting mechanism is not used if
encryption and decryption services are provided in the AC. encryption and decryption services are provided in the AC.
0 1 2 0 1 2
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Radio ID |Num Of Entries | Type |MAC Address... | Radio ID |Num Of Entries | Length |MAC Address...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 15 for Decryption Error Report Type: 15 for Decryption Error Report
Length: >= 9 Length: >= 9
Radio ID: The Radio Identifier refers to an interface index on the Radio ID: The Radio Identifier refers to an interface index on the
WTP. WTP.
Num of Entries: The number of instances of the Type/MAC Addresses Num of Entries: The number of instances of the Type/MAC Addresses
fields in the array. fields in the array.
Type: The format of the following MAC Address field. One of the Length: The length of the MAC Address field.
following values are supported:
1 - MAC-48 or EUI-48 [18], which is a 48 bit MAC Address.
2 - EUI-64 [19] which is a 64 bit MAC Address.
MAC Address: MAC addresses of the station that has caused MAC Address: MAC addresses of the station that has caused
decryption errors. decryption errors.
4.5.16. Decryption Error Report Period 4.6.16. Decryption Error Report Period
The Decryption Error Report Period message element value is used by The Decryption Error Report Period message element value is used by
the AC to inform the WTP how frequently it should send decryption the AC to inform the WTP how frequently it should send decryption
error report messages. Note that this error reporting mechanism is error report messages. Note that this error reporting mechanism is
not used if encryption and decryption services are provided in the not used if encryption and decryption services are provided in the
AC. AC.
0 1 2 0 1 2
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 65, line 20 skipping to change at page 62, line 36
Type: 16 for Decryption Error Report Period Type: 16 for Decryption Error Report Period
Length: 3 Length: 3
Radio ID: The Radio Identifier refers to an interface index on the Radio ID: The Radio Identifier refers to an interface index on the
WTP. WTP.
Report Interval: A 16-bit unsigned integer indicating the time, in Report Interval: A 16-bit unsigned integer indicating the time, in
seconds. The default value for this message element can be found seconds. The default value for this message element can be found
in Section 4.7.8. in Section 4.8.8.
4.5.17. Delete MAC ACL Entry 4.6.17. Delete MAC ACL Entry
The Delete MAC ACL Entry message element is used by an AC to delete a The Delete MAC ACL Entry message element is used by an AC to delete a
MAC ACL entry on a WTP, ensuring that the WTP provides service to the MAC ACL entry on a WTP, ensuring that the WTP provides service to the
MAC addresses provided in the message. MAC addresses provided in the message.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Num of Entries| Type | MAC Address ... | Num of Entries| Length | MAC Address ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 17 for Delete MAC ACL Entry Type: 17 for Delete MAC ACL Entry
Length: >= 8 Length: >= 8
Num of Entries: The number of instances of the Type/MAC Addresses Num of Entries: The number of instances of the Type/MAC Addresses
fields in the array. fields in the array.
Type: The format of the following MAC Address field. One of the Length: The length of the MAC Address field.
following values are supported:
1 - MAC-48 or EUI-48 [18], which is a 48 bit MAC Address.
2 - EUI-64 [19] which is a 64 bit MAC Address.
MAC Address: An array of MAC Addresses to delete from the ACL. MAC Address: An array of MAC Addresses to delete from the ACL.
4.5.18. Delete Station 4.6.18. Delete Station
The Delete Station message element is used by the AC to inform a WTP The Delete Station message element is used by the AC to inform a WTP
that it should no longer provide service to a particular station. that it should no longer provide service to a particular station.
The WTP MUST terminate service to the station immediately upon The WTP MUST terminate service to the station immediately upon
receiving this message element. receiving this message element.
The transmission of a Delete Station message element could occur for The transmission of a Delete Station message element could occur for
various reasons, including for administrative reasons, or if the various reasons, including for administrative reasons, or if the
station has roamed to another WTP. station has roamed to another WTP.
The Delete Station message element MAY be sent by the WTP, in the WTP The Delete Station message element MAY be sent by the WTP, in the WTP
Event Request message, to inform the AC that a particular station is Event Request message, to inform the AC that a particular station is
no longer being provided service. This could occur as a result of an no longer being provided service. This could occur as a result of an
Idle Timeout (see section 4.4.43), due to internal resource shortages Idle Timeout (see section 4.4.43), due to internal resource shortages
or for some other reason. or for some other reason.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Radio ID | Type | MAC Address... | Radio ID | Length | MAC Address...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 18 for Delete Station Type: 18 for Delete Station
Length: >= 8 Length: >= 8
Radio ID: An 8-bit value representing the radio Radio ID: An 8-bit value representing the radio
Type: The format of the following MAC Address field. One of the Length: The length of the MAC Address field.
following values are supported:
1 - MAC-48 or EUI-48 [18], which is a 48 bit MAC Address.
2 - EUI-64 [19] which is a 64 bit MAC Address.
MAC Address: The station's MAC Address MAC Address: The station's MAC Address
4.5.19. Delete Static MAC ACL Entry 4.6.19. Delete Static MAC ACL Entry
The Delete Static MAC ACL Entry message element is used by an AC to The Delete Static MAC ACL Entry message element is used by an AC to
delete a previously added static MAC ACL entry on a WTP, ensuring delete a previously added static MAC ACL entry on a WTP, ensuring
that the WTP provides service to the MAC addresses provided in the that the WTP provides service to the MAC addresses provided in the
message. message.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Num of Entries| Type | MAC Address ... | Num of Entries| Length | MAC Address ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 19 for Delete Static MAC ACL Entry Type: 19 for Delete Static MAC ACL Entry
Length: >= 8 Length: >= 8
Num of Entries: The number of instances of the Type/MAC Addresses Num of Entries: The number of instances of the Type/MAC Addresses
fields in the array. fields in the array.
Type: The format of the following MAC Address field. One of the Length: The length of the MAC Address field.
following values are supported:
1 - MAC-48 or EUI-48 [18], which is a 48 bit MAC Address.
2 - EUI-64 [19] which is a 64 bit MAC Address.
MAC Address: An array of MAC Addresses to delete from the static MAC Address: An array of MAC Addresses to delete from the static
MAC ACL entry. MAC ACL entry.
4.5.20. Discovery Type 4.6.20. Discovery Type
The Discovery Type message element is used by the WTP to indicate how The Discovery Type message element is used by the WTP to indicate how
it has come to know about the existence of the AC to which it is it has come to know about the existence of the AC to which it is
sending the Discovery Request message. sending the Discovery Request message.
0 0
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Discovery Type| | Discovery Type|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
skipping to change at page 67, line 48 skipping to change at page 65, line 4
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Type: 20 for Discovery Type Type: 20 for Discovery Type
Length: 1 Length: 1
Discovery Type: An 8-bit value indicating how the WTP discovered Discovery Type: An 8-bit value indicating how the WTP discovered
the AC. The following values are supported: the AC. The following values are supported:
0 - Unknown 0 - Unknown
1 - Static Configuration 1 - Static Configuration
2 - DHCP 2 - DHCP
3 - DNS 3 - DNS
4 - AC Referral (used when the AC was configured either through 4 - AC Referral (used when the AC was configured either through
the AC IPv4 List or AC IPv6 List message element) the AC IPv4 List or AC IPv6 List message element)
4.5.21. Duplicate IPv4 Address 4.6.21. Duplicate IPv4 Address
The Duplicate IPv4 Address message element is used by a WTP to inform The Duplicate IPv4 Address message element is used by a WTP to inform
an AC that it has detected another IP device using the same IP an AC that it has detected another IP device using the same IP
address that the WTP is currently using. address that the WTP is currently using.
The WTP MUST transmit this message element with the status set to 1 The WTP MUST transmit this message element with the status set to 1
after it has detected a duplicate IP address. When the WTP detects after it has detected a duplicate IP address. When the WTP detects
that the duplicate IP address has been cleared, it MUSY send this that the duplicate IP address has been cleared, it MUSY send this
message element with the status set to 0. message element with the status set to 0.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address | | IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status | Type | MAC Address ... | Status | Length | MAC Address ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 21 for Duplicate IPv4 Address Type: 21 for Duplicate IPv4 Address
Length: >= 12 Length: >= 12
IP Address: The IP Address currently used by the WTP. IP Address: The IP Address currently used by the WTP.
Status: The status of the duplicate IP address. The value MUST be Status: The status of the duplicate IP address. The value MUST be
set to 1 when a duplicate address is detected, and 0 when the set to 1 when a duplicate address is detected, and 0 when the
duplicate address has been cleared. duplicate address has been cleared.
Type: The format of the following MAC Address field. One of the Length: The length of the MAC Address field.
following values are supported:
1 - MAC-48 or EUI-48 [18], which is a 48 bit MAC Address.
2 - EUI-64 [19] which is a 64 bit MAC Address.
MAC Address: The MAC Address of the offending device. MAC Address: The MAC Address of the offending device.
4.5.22. Duplicate IPv6 Address 4.6.22. Duplicate IPv6 Address
The Duplicate IPv6 Address message element is used by a WTP to inform The Duplicate IPv6 Address message element is used by a WTP to inform
an AC that it has detected another host using the same IP address an AC that it has detected another host using the same IP address
that the WTP is currently using. that the WTP is currently using.
The WTP MUST transmit this message element with the status set to 1 The WTP MUST transmit this message element with the status set to 1
after it has detected a duplicate IP address. When the WTP detects after it has detected a duplicate IP address. When the WTP detects
that the duplicate IP address has been cleared, it MUST send this that the duplicate IP address has been cleared, it MUST send this
message element with the status set to 0. message element with the status set to 0.
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address | | IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address | | IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address | | IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address | | IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status | Type | MAC Address ... | Status | Length | MAC Address ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 23 for Duplicate IPv6 Address Type: 23 for Duplicate IPv6 Address
Length: >= 24 Length: >= 24
IP Address: The IP Address currently used by the WTP. IP Address: The IP Address currently used by the WTP.
Status: The status of the duplicate IP address. The value MUST be Status: The status of the duplicate IP address. The value MUST be
set to 1 when a duplicate address is detected, and 0 when the set to 1 when a duplicate address is detected, and 0 when the
duplicate address has been cleared. duplicate address has been cleared.
Type: The format of the following MAC Address field. One of the Length: The length of the MAC Address field.
following values are supported:
1 - MAC-48 or EUI-48 [18], which is a 48 bit MAC Address.
2 - EUI-64 [19] which is a 64 bit MAC Address.
MAC Address: The MAC Address of the offending device. MAC Address: The MAC Address of the offending device.
4.5.23. Idle Timeout 4.6.23. Idle Timeout
The Idle Timeout message element is sent by the AC to the WTP to The Idle Timeout message element is sent by the AC to the WTP to
provide the idle timeout value that the WTP SHOULD enforce for its provide the idle timeout value that the WTP SHOULD enforce for its
active stations. The value applies to all radios on the WTP. active stations. The value applies to all radios on the WTP.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timeout | | Timeout |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 70, line 16 skipping to change at page 67, line 4
The Idle Timeout message element is sent by the AC to the WTP to The Idle Timeout message element is sent by the AC to the WTP to
provide the idle timeout value that the WTP SHOULD enforce for its provide the idle timeout value that the WTP SHOULD enforce for its
active stations. The value applies to all radios on the WTP. active stations. The value applies to all radios on the WTP.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timeout | | Timeout |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 23 for Idle Timeout Type: 23 for Idle Timeout
Length: 4 Length: 4
Timeout: The current idle timeout to be enforced by the WTP. The Timeout: The current idle timeout to be enforced by the WTP. The
default value for this message element is specified in default value for this message element is specified in
Section 4.7.5. Section 4.8.5.
4.5.24. Image Data 4.6.24. Image Data
The Image Data message element is present in the Image Data Request The Image Data message element is present in the Image Data Request
message sent by the AC and contains the following fields. message sent by the AC and contains the following fields.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode | Value ... | Opcode | Value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 71, line 4 skipping to change at page 67, line 35
Length: >= 1 Length: >= 1
Opcode: An 8-bit value representing the transfer opcode. The Opcode: An 8-bit value representing the transfer opcode. The
following values are supported: following values are supported:
1 - Image data is included 1 - Image data is included
2 - Last Image Data Block is included (EOF) 2 - Last Image Data Block is included (EOF)
5 - An error occurred. Transfer is aborted 5 - An error occurred. Transfer is aborted
Value: The Image Data field contains up to 1024 characters. If the Value: The Image Data field contains up to 1024 characters. If the
block being sent is the last one, the Opcode is set to 2. The AC block being sent is the last one, the Opcode is set to 2. The AC
MAY opt to abort the data transfer by setting the Opcode to 5. MAY opt to abort the data transfer by setting the Opcode to 5.
When the Opcode is 5, the Value field has a zero length. When the Opcode is 5, the Value field has a zero length.
4.5.25. Image Identifier 4.6.25. Image Identifier
The Image Identifier message element is sent by the AC to the WTP and The Image Identifier message element is sent by the AC to the WTP and
is used to indicate the expected active software version that is to is used to indicate the expected active software version that is to
be run on the WTP. The value is a variable length UTF-8 encoded be run on the WTP. The value is a variable length UTF-8 encoded
string, which is NOT zero terminated. string, which is NOT zero terminated.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Vendor Identifier | | Vendor Identifier |
skipping to change at page 71, line 31 skipping to change at page 68, line 20
| Value... | Value...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 25 for Image Identifier Type: 25 for Image Identifier
Length: >= 1 Length: >= 1
Value: A variable length UTF-8 encoded string containing the Value: A variable length UTF-8 encoded string containing the
firmware identifier to be run on the WTP. firmware identifier to be run on the WTP.
4.5.26. Image Information 4.6.26. Image Information
The Image Information message element is present in the Image Data The Image Information message element is present in the Image Data
Response message sent by the AC to the WTP and contains the following Response message sent by the AC to the WTP and contains the following
fields. fields.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| File Size | Hash | | File Size | Hash |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 72, line 24 skipping to change at page 69, line 15
#include <md5.h> #include <md5.h>
CapwapCreateHash(char *hash, char *image, int image_len) CapwapCreateHash(char *hash, char *image, int image_len)
{ {
MD_CTX context; MD_CTX context;
MDInit (&context); MDInit (&context);
MDUpdate (&context, buffer, len); MDUpdate (&context, buffer, len);
MDFinal (hash, &context); MDFinal (hash, &context);
} }
4.5.27. Initiate Download 4.6.27. Initiate Download
The Initiate Download message element is used by the AC to inform the The Initiate Download message element is used by the AC to inform the
WTP that the WTP should initiate a firmware upgrade. The WTP WTP that the WTP SHOULD initiate a firmware upgrade. The WTP
subsequently transmits an Image Data Request message which includes subsequently transmits an Image Data Request message which includes
the Image Download message element. This message element does not the Image Download message element. This message element does not
contain any data. contain any data.
Type: 27 for Initiate Download Type: 27 for Initiate Download
Length: 0 Length: 0
4.5.28. Location Data 4.6.28. Location Data
The Location Data message element is a variable length byte UTF-8 The Location Data message element is a variable length byte UTF-8
encoded string containing user defined location information (e.g. encoded string containing user defined location information (e.g.
"Next to Fridge"). This information is configurable by the network "Next to Fridge"). This information is configurable by the network
administrator, and allows the WTP location to be determined. The administrator, and allows the WTP location to be determined. The
string is not zero terminated. string is not zero terminated.
0 0
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-
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encoded string containing user defined location information (e.g. encoded string containing user defined location information (e.g.
"Next to Fridge"). This information is configurable by the network "Next to Fridge"). This information is configurable by the network
administrator, and allows the WTP location to be determined. The administrator, and allows the WTP location to be determined. The
string is not zero terminated. string is not zero terminated.
0 0
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-
| Location ... | Location ...
+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-
Type: 28 for Location Data Type: 28 for Location Data
Length: > 0 Length: > 0
Location: A non-zero terminated UTF-8 encoded string containing the Location: A non-zero terminated UTF-8 encoded string containing the
WTP location. WTP location.
4.5.29. Maximum Message Length 4.6.29. Maximum Message Length
The Maximum Message Length message element is included in the Join The Maximum Message Length message element is included in the Join
Request message by the WTP to indicate the maximum CAPWAP message Request message by the WTP to indicate the maximum CAPWAP message
length that it supports to the AC. The Maximum Message Length length that it supports to the AC. The Maximum Message Length
message element is optionally included in Join Response message by message element is optionally included in Join Response message by
the AC to indicate the maximum CAPWAP message length that it supports the AC to indicate the maximum CAPWAP message length that it supports
to the WTP. to the WTP.
0 1 2 0 1 2
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
skipping to change at page 73, line 33 skipping to change at page 70, line 21
| Maximum Message Length | | Maximum Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
Type: 29 for Maximim Message Length Type: 29 for Maximim Message Length
Length: 2 Length: 2
Maximum Message Length An 16-bit unsigned integer indicating the Maximum Message Length An 16-bit unsigned integer indicating the
maximum message length. maximum message length.
4.5.30. MTU Discovery Padding 4.6.30. MTU Discovery Padding
The MTU Discovery Padding message element is used as padding to The MTU Discovery Padding message element is used as padding to
perform MTU discovery, and MUST contain octets of value 0xFF, of any perform MTU discovery, and MUST contain octets of value 0xFF, of any
length length
0 0
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Padding... | Padding...
+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-
skipping to change at page 74, line 4 skipping to change at page 70, line 34
perform MTU discovery, and MUST contain octets of value 0xFF, of any perform MTU discovery, and MUST contain octets of value 0xFF, of any
length length
0 0
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Padding... | Padding...
+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-
Type: 30 for MTU Discovery Padding Type: 30 for MTU Discovery Padding
Length: variable Length: variable
Pad: A variable length pad. Pad: A variable length pad.
4.5.31. Radio Administrative State 4.6.31. Radio Administrative State
The Radio Administrative State message element is used to communicate The Radio Administrative State message element is used to communicate
the state of a particular radio. The Radio Administrative State the state of a particular radio. The Radio Administrative State
message element is sent by the AC to change the state of the WTP. message element is sent by the AC to change the state of the WTP.
The WTP saves the value, to ensure that it remains across WTP resets. The WTP saves the value, to ensure that it remains across WTP resets.
The WTP communicates this message element during the configuration The WTP communicates this message element during the configuration
phase, in the Configuration Status Request message, to ensure that AC phase, in the Configuration Status Request message, to ensure that AC
has the WTP radio current administrative state settings. The message has the WTP radio current administrative state settings. The message
element contains the following fields. element contains the following fields.
skipping to change at page 74, line 30 skipping to change at page 71, line 16
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Radio ID | Admin State | | Radio ID | Admin State |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 31 for Radio Administrative State Type: 31 for Radio Administrative State
Length: 2 Length: 2
Radio ID: An 8-bit value representing the radio to configure. The Radio ID: An 8-bit value representing the radio to configure. The
Radio ID field may also include the value of 0xff, which is used Radio ID field MAY also include the value of 0xff, which is used
to identify the WTP. If an AC wishes to change the administrative to identify the WTP. If an AC wishes to change the administrative
state of a WTP, it includes 0xff in the Radio ID field. state of a WTP, it includes 0xff in the Radio ID field.
Admin State: An 8-bit value representing the administrative state Admin State: An 8-bit value representing the administrative state
of the radio. The default value for the Admin State field is of the radio. The default value for the Admin State field is
listed in Section 4.7.1. The following values are supported: listed in Section 4.8.1. The following values are supported:
1 - Enabled 1 - Enabled
2 - Disabled 2 - Disabled
4.5.32. Radio Operational State 4.6.32. Radio Operational State
The Radio Operational State message element is sent by the WTP to the The Radio Operational State message element is sent by the WTP to the
AC to communicate a radio's operational state. This message element AC to communicate a radio's operational state. This message element
is included in the Configuration Update Response message by the WTP is included in the Configuration Update Response message by the WTP
if it was requested to change the state of its radio, via the Radio if it was requested to change the state of its radio, via the Radio
Administrative State message element, but was unable to comply to the Administrative State message element, but was unable to comply to the
request. This message element is included in the Change State Event request. This message element is included in the Change State Event
message when a WTP radio state was changed unexpectedly. This could message when a WTP radio state was changed unexpectedly. This could
occur due to a hardware failure. Note that the operational state occur due to a hardware failure. Note that the operational state
setting is not saved on the WTP, and therefore does not remain across setting is not saved on the WTP, and therefore does not remain across
skipping to change at page 75, line 37 skipping to change at page 72, line 24
supported: supported:
0 - Normal 0 - Normal
1 - Radio Failure 1 - Radio Failure
2 - Software Failure 2 - Software Failure
3 - Administratively Set 3 - Administratively Set
4.5.33. Result Code 4.6.33. Result Code
The Result Code message element value is a 32-bit integer value, The Result Code message element value is a 32-bit integer value,
indicating the result of the Request message corresponding to the indicating the result of the Request message corresponding to the
Sequence Number included in the Response message. Sequence Number included in the Response message.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Result Code | | Result Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 77, line 4 skipping to change at page 73, line 35
14 Image Data Error (Invalid Checksum) 14 Image Data Error (Invalid Checksum)
15 Image Data Error (Invalid Data Length) 15 Image Data Error (Invalid Data Length)
16 Image Data Error (Other Error) 16 Image Data Error (Other Error)
17 Image Data Error (Image Already Present) 17 Image Data Error (Image Already Present)
18 Message Unexpected (Invalid in current state) 18 Message Unexpected (Invalid in current state)
19 Message Unexpected (Unrecognized Request) 19 Message Unexpected (Unrecognized Request)
20 Failure - Missing Mandatory Message Element 20 Failure - Missing Mandatory Message Element
21 Failure - Unrecognized Message Element 21 Failure - Unrecognized Message Element
4.5.34. Returned Message Element 4.6.34. Returned Message Element
The Returned Message Element is sent by the WTP in the Change State The Returned Message Element is sent by the WTP in the Change State
Event Request message to communicate to the AC which message elements Event Request message to communicate to the AC which message elements
in the Configuration Status Response it was unable to apply locally. in the Configuration Status Response it was unable to apply locally.
The Returned Message Element message element contains a result code The Returned Message Element message element contains a result code
indicating the reason that the configuration could not be applied, indicating the reason that the configuration could not be applied,
and encapsulates the failed message element. and encapsulates the failed message element.
0 1 2 0 1 2
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
skipping to change at page 77, line 44 skipping to change at page 74, line 30
2 - Unsupported Message Element 2 - Unsupported Message Element
3 - Unknown Message Element Value 3 - Unknown Message Element Value
4 - Unsupported Message Element Value 4 - Unsupported Message Element Value
Message Element: The Message Element field encapsulates the message Message Element: The Message Element field encapsulates the message
element sent by the AC in the Configuration Status Response element sent by the AC in the Configuration Status Response
message that caused the error. message that caused the error.
4.5.35. Session ID 4.6.35. Session ID
The Session ID message element value contains a randomly generated The Session ID message element value contains a randomly generated
unsigned 32-bit integer. unsigned 32-bit integer.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session ID | | Session ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 35 for Session ID Type: 35 for Session ID
Length: 16 Length: 16
Session ID: A 32-bit unsigned integer used as a random session Session ID: A 32-bit unsigned integer used as a random session
identifier identifier
4.5.36. Statistics Timer 4.6.36. Statistics Timer
The Statistics Timer message element value is used by the AC to The Statistics Timer message element value is used by the AC to
inform the WTP of the frequency with which it expects to receive inform the WTP of the frequency with which it expects to receive
updated statistics. updated statistics.
0 1 0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Statistics Timer | | Statistics Timer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 36 for Statistics Timer Type: 36 for Statistics Timer
Length: 2 Length: 2
Statistics Timer: A 16-bit unsigned integer indicating the time, in Statistics Timer: A 16-bit unsigned integer indicating the time, in
seconds. The default value for this timer is specified in seconds. The default value for this timer is specified in
Section 4.6.13. Section 4.7.12.
4.5.37. Vendor Specific Payload 4.6.37. Vendor Specific Payload
The Vendor Specific Payload message element is used to communicate The Vendor Specific Payload message element is used to communicate
vendor specific information between the WTP and the AC. The message vendor specific information between the WTP and the AC. The message
element uses the following format: element uses the following format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Vendor Identifier | | Vendor Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 79, line 4 skipping to change at page 75, line 38
vendor specific information between the WTP and the AC. The message vendor specific information between the WTP and the AC. The message
element uses the following format: element uses the following format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Vendor Identifier | | Vendor Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Element ID | Value... | | Element ID | Value... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 37 for Vendor Specific Type: 37 for Vendor Specific
Length: >= 7 Length: >= 7
Vendor Identifier: A 32-bit value containing the IANA assigned "SMI Vendor Identifier: A 32-bit value containing the IANA assigned "SMI
Network Management Private Enterprise Codes" [16] Network Management Private Enterprise Codes" [14]
Element ID: A 16-bit Element Identifier which is managed by the Element ID: A 16-bit Element Identifier which is managed by the
vendor. vendor.
Value: The value associated with the vendor specific element. Value: The value associated with the vendor specific element.
4.5.38. WTP Board Data 4.6.38. WTP Board Data
The WTP Board Data message element is sent by the WTP to the AC and The WTP Board Data message element is sent by the WTP to the AC and
contains information about the hardware present. contains information about the hardware present.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Vendor Identifier | | Vendor Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=0 | Length | | Type=0 | Length |
skipping to change at page 80, line 17 skipping to change at page 77, line 5
2 - Board ID: A hardware identifier, which MAY be included in 2 - Board ID: A hardware identifier, which MAY be included in
the WTP Board Data mesage element. the WTP Board Data mesage element.
3 - Board Revision A revision number of the board, which MAY be 3 - Board Revision A revision number of the board, which MAY be
included in the WTP Board Data message element. included in the WTP Board Data message element.
4 - Base MAC Addres The WTP's Base MAC Address, which MAY be 4 - Base MAC Addres The WTP's Base MAC Address, which MAY be
assigned to the primary Ethernet interface. assigned to the primary Ethernet interface.
4.5.39. WTP Descriptor 4.6.39. WTP Descriptor
The WTP Descriptor message element is used by a WTP to communicate The WTP Descriptor message element is used by a WTP to communicate
its current hardware and software (firmware) configuration. The its current hardware and software (firmware) configuration. The
value contains the following fields. value contains the following fields.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max Radios | Radios in use | Encryption Capabilities | | Max Radios | Radios in use | Encryption Capabilities |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 81, line 43 skipping to change at page 78, line 36
2 - Boot Version: The WTP boot loader version number. 2 - Boot Version: The WTP boot loader version number.
3 - Other Software Version: The WTP non-running software 3 - Other Software Version: The WTP non-running software
(firmware) version number. (firmware) version number.
Length: Length of vendor specific encoding of WTP information. Length: Length of vendor specific encoding of WTP information.
Value: Vendor specific data of WTP information encoded in the UTF-8 Value: Vendor specific data of WTP information encoded in the UTF-8
format. format.
4.5.40. WTP Fallback 4.6.40. WTP Fallback
The WTP Fallback message element is sent by the AC to the WTP to The WTP Fallback message element is sent by the AC to the WTP to
enable or disable automatic CAPWAP fallback in the event that a WTP enable or disable automatic CAPWAP fallback in the event that a WTP
detects its preferred AC, and is not currently connected to it. detects its preferred AC, and is not currently connected to it.
0 0
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Mode | | Mode |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
skipping to change at page 82, line 12 skipping to change at page 79, line 4
enable or disable automatic CAPWAP fallback in the event that a WTP enable or disable automatic CAPWAP fallback in the event that a WTP
detects its preferred AC, and is not currently connected to it. detects its preferred AC, and is not currently connected to it.
0 0
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Mode | | Mode |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Type: 40 for WTP Fallback Type: 40 for WTP Fallback
Length: 1 Length: 1
Mode: The 8-bit value indicates the status of automatic CAPWAP Mode: The 8-bit value indicates the status of automatic CAPWAP
fallback on the WTP. When enabled, if the WTP detects that its fallback on the WTP. When enabled, if the WTP detects that its
primary AC is available, and that the WTP is not connected to the primary AC is available, and that the WTP is not connected to the
primary AC, the WTP SHOULD automatically disconnect from its primary AC, the WTP SHOULD automatically disconnect from its
current AC and reconnect to its primary AC. If disabled, the WTP current AC and reconnect to its primary AC. If disabled, the WTP
will only reconnect to its primary AC through manual intervention will only reconnect to its primary AC through manual intervention
(e.g., through the Reset Request message). The default value for (e.g., through the Reset Request message). The default value for
this field is specified in Section 4.7.10. The following values this field is specified in Section 4.8.10. The following values
are supported: are supported:
1 - Enabled 1 - Enabled
2 - Disabled 2 - Disabled
4.5.41. WTP Frame Tunnel Mode 4.6.41. WTP Frame Tunnel Mode
The WTP Frame Tunnel Mode message element allows the WTP to The WTP Frame Tunnel Mode message element allows the WTP to
communicate the tunneling modes of operation which it supports to the communicate the tunneling modes of operation which it supports to the
AC. A WTP that advertises support for all types allows the AC to AC. A WTP that advertises support for all types allows the AC to
select which type will be used, based on its local policy. select which type will be used, based on its local policy.
0 0
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Tunnel Mode | | Tunnel Mode |
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modes for station data that are supported by the WTP. The modes for station data that are supported by the WTP. The
following values are supported: following values are supported:
1 - Local Bridging: When Local Bridging is used, the WTP does 1 - Local Bridging: When Local Bridging is used, the WTP does
not tunnel user traffic to the AC; all user traffic is locally not tunnel user traffic to the AC; all user traffic is locally
bridged. This value MUST NOT be used when the WTP MAC Type is bridged. This value MUST NOT be used when the WTP MAC Type is
set to Split-MAC. set to Split-MAC.
2 - 802.3 Frame Tunnel Mode: The 802.3 Frame Tunnel Mode 2 - 802.3 Frame Tunnel Mode: The 802.3 Frame Tunnel Mode
requires the WTP and AC to encapsulate all user payload as requires the WTP and AC to encapsulate all user payload as
native IEEE 802.3 frames (see Section 4.3). All user traffic native IEEE 802.3 frames (see Section 4.4). All user traffic
is tunneled to the AC. This value MUST NOT be used when the is tunneled to the AC. This value MUST NOT be used when the
WTP MAC Type is set to Split-MAC. WTP MAC Type is set to Split-MAC.
4 - Native Frame Tunnel Mode: Native Frame Tunnel mode requires 4 - Native Frame Tunnel Mode: Native Frame Tunnel mode requires
the WTP and AC to encapsulate all user payloads as native the WTP and AC to encapsulate all user payloads as native
wireless frames, as defined by the wireless binding (see for wireless frames, as defined by the wireless binding (see for
example Section 4.3). example Section 4.4).
7 - All: The WTP is capable of supporting all frame tunnel 7 - All: The WTP is capable of supporting all frame tunnel
modes. modes.
4.5.42. WTP IPv4 IP Address 4.6.42. WTP IPv4 IP Address
The WTP IPv4 address is used to perform NAT detection. The WTP IPv4 address is used to perform NAT detection.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| WTP IPv4 IP Address | | WTP IPv4 IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 42 for WTP IPv4 IP Address Type: 42 for WTP IPv4 IP Address
Length: 4 Length: 4
WTP IPv4 IP Address: The IPv4 address from which the WTP is sending WTP IPv4 IP Address: The IPv4 address from which the WTP is sending
packets. This field is used for NAT detection. packets. This field is used for NAT detection.
4.5.43. WTP MAC Type 4.6.43. WTP IPv6 IP Address
The WTP IPv6 address is used to perform NAT detection (e.g., IPv4 to
IPv6 NAT to help with technology transition).
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| WTP IPv6 IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| WTP IPv6 IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| WTP IPv6 IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| WTP IPv6 IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 43 for WTP IPv6 IP Address
Length: 32
WTP IPv6 IP Address: The IPv6 address from which the WTP is sending
packets. This field is used for NAT detection.
4.6.44. WTP MAC Type
The WTP MAC-Type message element allows the WTP to communicate its The WTP MAC-Type message element allows the WTP to communicate its
mode of operation to the AC. A WTP that advertises support for both mode of operation to the AC. A WTP that advertises support for both
modes allows the AC to select the mode to use, based on local policy. modes allows the AC to select the mode to use, based on local policy.
0 0
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| MAC Type | | MAC Type |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Type: 43 for WTP MAC Type
Type: 44 for WTP MAC Type
Length: 1 Length: 1
MAC Type: The MAC mode of operation supported by the WTP. The MAC Type: The MAC mode of operation supported by the WTP. The
following values are supported following values are supported
0 - Local-MAC: Local-MAC is the default mode that MUST be 0 - Local-MAC: Local-MAC is the default mode that MUST be
supported by all WTPs. supported by all WTPs.
1 - Split-MAC: Split-MAC support is optional, and allows the AC 1 - Split-MAC: Split-MAC support is optional, and allows the AC
to receive and process native wireless frames. to receive and process native wireless frames.
2 - Both: WTP is capable of supporting both Local-MAC and Split- 2 - Both: WTP is capable of supporting both Local-MAC and Split-
MAC. MAC.
4.5.44. WTP Name 4.6.45. WTP Name
The WTP Name message element is a variable length byte UTF-8 encoded The WTP Name message element is a variable length byte UTF-8 encoded
string. The string is not zero terminated. string. The string is not zero terminated.
0 0
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-
| WTP Name ... | WTP Name ...
+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-
Type: 45 for WTP Name
Type: 44 for WTP Name
Length: variable Length: variable
WTP Name: A non-zero terminated UTF-8 encoded string containing the WTP Name: A non-zero terminated UTF-8 encoded string containing the
WTP name. WTP name.
4.5.45. WTP Operational Statistics 4.6.46. WTP Operational Statistics
The WTP Operational Statistics message element is sent by the WTP to The WTP Operational Statistics message element is sent by the WTP to
the AC to provide statistics related to the operation of the WTP. the AC to provide statistics related to the operation of the WTP.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Radio ID | Tx Queue Level | Wireless Link Frames per Sec | | Radio ID | Tx Queue Level | Wireless Link Frames per Sec |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 45 for WTP Operational Statistics
Type: 46 for WTP Operational Statistics
Length: 4 Length: 4
Radio ID: The radio ID of the radio to which the statistics apply. Radio ID: The radio ID of the radio to which the statistics apply.
Wireless Transmit Queue Level: The percentage of Wireless Transmit Wireless Transmit Queue Level: The percentage of Wireless Transmit
queue utilization, calculated as the sum of utilized transmit queue utilization, calculated as the sum of utilized transmit
queue lengths divided by the sum of maximum transmit queue queue lengths divided by the sum of maximum transmit queue
lengths, multiplied by 100. The Wireless Transmit Queue Level is lengths, multiplied by 100. The Wireless Transmit Queue Level is
representative of congestion conditions over wireless interfaces representative of congestion conditions over wireless interfaces
between the WTP and stations. between the WTP and stations.
Wireless Link Frames per Sec: The number of frames transmitted or Wireless Link Frames per Sec: The number of frames transmitted or
received per second by the WTP over the air interface. received per second by the WTP over the air interface.
4.5.46. WTP Radio Statistics 4.6.47. WTP Radio Statistics
The WTP Radio Statistics message element is sent by the WTP to the AC The WTP Radio Statistics message element is sent by the WTP to the AC
to communicate statistics on radio behavior and reasons why the WTP to communicate statistics on radio behavior and reasons why the WTP
radio has been reset. radio has been reset.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Radio ID | Last Fail Type| Reset Count | | Radio ID | Last Fail Type| Reset Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SW Failure Count | HW Failure Count | | SW Failure Count | HW Failure Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Other Failure Count | Unknown Failure Count | | Other Failure Count | Unknown Failure Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Config Update Count | Channel Change Count | | Config Update Count | Channel Change Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Band Change Count | Current Noise Floor | | Band Change Count | Current Noise Floor |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 46 for WTP Radio Statistics Type: 47 for WTP Radio Statistics
Length: 20 Length: 20
Radio ID: The radio ID of the radio to which the statistics apply. Radio ID: The radio ID of the radio to which the statistics apply.
Last Failure Type: The last WTP failure. The following values are Last Failure Type: The last WTP failure. The following values are
supported: supported:
0 - Statistic Not Supported 0 - Statistic Not Supported
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Channel Change Count: The number of times that the radio channel Channel Change Count: The number of times that the radio channel
has been changed. has been changed.
Band Change Count: The number of times that the radio has changed Band Change Count: The number of times that the radio has changed
frequency bands. frequency bands.
Current Noise Floor: A signed integer which indicates the noise Current Noise Floor: A signed integer which indicates the noise
floor of the radio receiver in units of dBm. floor of the radio receiver in units of dBm.
4.5.47. WTP Reboot Statistics 4.6.48. WTP Reboot Statistics
The WTP Reboot Statistics message element is sent by the WTP to the The WTP Reboot Statistics message element is sent by the WTP to the
AC to communicate reasons why WTP reboots have occurred. AC to communicate reasons why WTP reboots have occurred.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reboot Count | AC Initiated Count | | Reboot Count | AC Initiated Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Failure Count | SW Failure Count | | Link Failure Count | SW Failure Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| HW Failure Count | Other Failure Count | | HW Failure Count | Other Failure Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unknown Failure Count |Last Failure Type| | Unknown Failure Count |Last Failure Type|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 47 for WTP Reboot Statistics Type: 48 for WTP Reboot Statistics
Length: 15 Length: 15
Reboot Count: The number of reboots that have occurred due to a WTP Reboot Count: The number of reboots that have occurred due to a WTP
crash. A value of 65535 implies that this information is not crash. A value of 65535 implies that this information is not
available on the WTP. available on the WTP.
AC Initiated Count: The number of reboots that have occurred at the AC Initiated Count: The number of reboots that have occurred at the
request of a CAPWAP protocol message, such as a change in request of a CAPWAP protocol message, such as a change in
configuration that required a reboot or an explicit CAPWAP configuration that required a reboot or an explicit CAPWAP
skipping to change at page 88, line 19 skipping to change at page 85, line 38
2 - Link Failure 2 - Link Failure
3 - Software Failure 3 - Software Failure
4 - Hardware Failure 4 - Hardware Failure
5 - Other Failure 5 - Other Failure
255 - Unknown (e.g., WTP doesn't keep track of info) 255 - Unknown (e.g., WTP doesn't keep track of info)
4.5.48. WTP Static IP Address Information 4.6.49. WTP Static IP Address Information
The WTP Static IP Address Information message element is used by an The WTP Static IP Address Information message element is used by an
AC to configure or clear a previously configured static IP address on AC to configure or clear a previously configured static IP address on
a WTP. a WTP.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address | | IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Netmask | | Netmask |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Gateway | | Gateway |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Static | | Static |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Type: 48 for WTP Static IP Address Information Type: 49 for WTP Static IP Address Information
Length: 13 Length: 13
IP Address: The IP Address to assign to the WTP. This field is IP Address: The IP Address to assign to the WTP. This field is
only valid if the static field is set to one. only valid if the static field is set to one.
Netmask: The IP Netmask. This field is only valid if the static Netmask: The IP Netmask. This field is only valid if the static
field is set to one. field is set to one.
Gateway: The IP address of the gateway. This field is only valid Gateway: The IP address of the gateway. This field is only valid
if the static field is set to one. if the static field is set to one.
Netmask: The IP Netmask. This field is only valid if the static Netmask: The IP Netmask. This field is only valid if the static
field is set to one. field is set to one.
Static: An 8-bit boolean stating whether the WTP should use a Static: An 8-bit boolean stating whether the WTP should use a
static IP address or not. A value of zero disables the static IP static IP address or not. A value of zero disables the static IP
address, while a value of one enables it. address, while a value of one enables it.
4.6. CAPWAP Protocol Timers 4.7. CAPWAP Protocol Timers
This section contains the CAPWAP timers. This section contains the CAPWAP timers.
4.6.1. ChangeStatePendingTimer 4.7.1. ChangeStatePendingTimer
The maximum time, in seconds, the AC will wait for the Change State The maximum time, in seconds, the AC will wait for the Change State
Event Request from the WTP after having transmitted a successful Event Request from the WTP after having transmitted a successful
Configuration Status Response message. The default value is 25 Configuration Status Response message. The default value is 25
seconds. seconds.
4.6.2. DataChannelDeadInterval 4.7.2. DataChannelDeadInterval
The minimum time, in seconds, a WTP MUST wait without having received The minimum time, in seconds, a WTP MUST wait without having received
a Data Channel Keep Alive packet before the destination for the Data a Data Channel Keep Alive packet before the destination for the Data
Channel Keep Alive packets may be considered dead. The value of this Channel Keep Alive packets may be considered dead. The value of this
timer MUST be no less than 2*DataChannelKeepAlive seconds and no timer MUST be no less than 2*DataChannelKeepAlive seconds and no
greater that 240 seconds. greater that 240 seconds.
Default: 5 Default: 5
4.6.3. DiscoveryInterval 4.7.3. DiscoveryInterval
The minimum time, in seconds, that a WTP MUST wait after receiving a The minimum time, in seconds, that a WTP MUST wait after receiving a
Discovery Response message, before initiating a DTLS handshake. Discovery Response message, before initiating a DTLS handshake.
Default: 5 Default: 5
4.6.4. DTLSSessionDelete 4.7.4. DTLSSessionDelete
The minimum time, in seconds, a WTP MUST wait for DTLS session The minimum time, in seconds, a WTP MUST wait for DTLS session
deletion. deletion.
Default: 5 Default: 5
4.6.5. EchoInterval 4.7.5. EchoInterval
The minimum time, in seconds, between sending Echo Request messages The minimum time, in seconds, between sending Echo Request messages
to the AC with which the WTP has joined. to the AC with which the WTP has joined.
Default: 30 Default: 30
4.6.6. KeyLifetime 4.7.6. MaxDiscoveryInterval
The maximum time, in seconds, which a CAPWAP DTLS session key is
valid.
Default: 28800
4.6.7. MaxDiscoveryInterval
The maximum time allowed between sending Discovery Request messages, The maximum time allowed between sending Discovery Request messages,
in seconds. This value MUST be no less than 2 seconds and no greater in seconds. This value MUST be no less than 2 seconds and no greater
than 180 seconds. than 180 seconds.
Default: 20 seconds. Default: 20 seconds.
4.6.8. MaxFailedDTLSSessionRetry 4.7.7. MaxFailedDTLSSessionRetry
The maximum number of failed DTLS session establishment attempts The maximum number of failed DTLS session establishment attempts
before the CAPWAP device enters a silent period. before the CAPWAP device enters a silent period.
Default: 3. Default: 3.
4.6.9. NeighborDeadInterval 4.7.8. NeighborDeadInterval
The minimum time, in seconds, a WTP MUST wait without having received The minimum time, in seconds, a WTP MUST wait without having received
an Echo Response message to its Echo Request message, before the an Echo Response message to its Echo Request message, before the
destination for the Echo Request may be considered dead. This value destination for the Echo Request may be considered dead. This value
MUST be no less than 2*EchoInterval seconds and no greater than 240 MUST be no less than 2*EchoInterval seconds and no greater than 240
seconds. seconds.
Default: 60 Default: 60
4.6.10. ResponseTimeout 4.7.9. ResponseTimeout
The minimum time, in seconds, in which the WTP or AC must respond to The minimum time, in seconds, in which the WTP or AC MUST respond to
a CAPWAP Request message. a CAPWAP Request message.
Default: 1 Default: 1
4.6.11. RetransmitInterval 4.7.10. RetransmitInterval
The minimum time, in seconds, in which a non-acknowledged CAPWAP The minimum time, in seconds, in which a non-acknowledged CAPWAP
packet will be retransmitted. packet will be retransmitted.
Default: 3 Default: 3
4.6.12. SilentInterval 4.7.11. SilentInterval
For a WTP, this is the minimum time, in seconds, a WTP MUST wait For a WTP, this is the minimum time, in seconds, a WTP MUST wait
before it MAY again send Discovery Request messages or attempt to a before it MAY again send Discovery Request messages or attempt to a
establish DTLS session. For an AC, this is the minimum time, in establish DTLS session. For an AC, this is the minimum time, in
seconds, during which the AC SHOULD ignore all CAPWAP and DTLS seconds, during which the AC SHOULD ignore all CAPWAP and DTLS
packets received from the WTP that is in the Sulking state. packets received from the WTP that is in the Sulking state.
Default: 30 Default: 30
4.6.13. StatisticsTimer 4.7.12. StatisticsTimer
The default Statistics Interval is 120 seconds. The default Statistics Interval is 120 seconds.
4.6.14. WaitDTLS 4.7.13. WaitDTLS
The maximum time, in seconds, a WTP MUST wait without having received The maximum time, in seconds, a WTP MUST wait without having received
a DTLS Handshake message from an AC. This timer must be greater than a DTLS Handshake message from an AC. This timer MUST be greater than
30 seconds. 30 seconds.
Default: 60 Default: 60
4.6.15. WaitJoin 4.7.14. WaitJoin
The maximum time, in seconds, after which the DTLS session has been The maximum time, in seconds, after which the DTLS session has been
established that the AC will wait before receiving a Join Request established that the AC will wait before receiving a Join Request
message. This timer must be greater than 30 seconds. message. This timer MUST be greater than 30 seconds.
Default: 60 Default: 60
4.7. CAPWAP Protocol Variables 4.8. CAPWAP Protocol Variables
A WTP or AC that implements the CAPWAP Discovery phase MUST allow for A WTP or AC that implements the CAPWAP Discovery phase MUST allow for
the following variables to be configured by system management; the following variables to be configured by system management;
default values are specified, making explicit configuration default values are specified, making explicit configuration
unnecessary in many cases. If the default values are explicitly unnecessary in many cases. If the default values are explicitly
overriden by the AC, the WTP MUST save the values sent by the AC. overriden by the AC, the WTP MUST save the values sent by the AC.
4.7.1. AdminState 4.8.1. AdminState
The default Administrative State value is enabled (1). The default Administrative State value is enabled (1).
4.7.2. DiscoveryCount 4.8.2. DiscoveryCount
The number of Discovery Request messages transmitted by a WTP to a The number of Discovery Request messages transmitted by a WTP to a
single AC. This is a monotonically increasing counter. single AC. This is a monotonically increasing counter.
4.7.3. FailedDTLSAuthFailCount 4.8.3. FailedDTLSAuthFailCount
The number of failed DTLS session establishment attempts due to The number of failed DTLS session establishment attempts due to
authentication failures. authentication failures.
4.7.4. FailedDTLSSessionCount 4.8.4. FailedDTLSSessionCount
The number of failed DTLS session establishment attempts. The number of failed DTLS session establishment attempts.
4.7.5. IdleTimeout 4.8.5. IdleTimeout
The default Idle Timeout is 300 seconds. The default Idle Timeout is 300 seconds.
4.7.6. MaxDiscoveries 4.8.6. MaxDiscoveries
The maximum number of Discovery Request messages that will be sent The maximum number of Discovery Request messages that will be sent
after a WTP boots. after a WTP boots.
Default: 10 Default: 10
4.7.7. MaxRetransmit 4.8.7. MaxRetransmit
The maximum number of retransmissions for a given CAPWAP packet The maximum number of retransmissions for a given CAPWAP packet
before the link layer considers the peer dead. before the link layer considers the peer dead.
Default: 5 Default: 5
4.7.8. ReportInterval 4.8.8. ReportInterval
The default Report Interval is 120 seconds. The default Report Interval is 120 seconds.
4.7.9. RetransmitCount 4.8.9. RetransmitCount
The number of retransmissions for a given CAPWAP packet. This is a The number of retransmissions for a given CAPWAP packet. This is a
monotonically increasing counter. monotonically increasing counter.
4.7.10. WTPFallBack 4.8.10. WTPFallBack
The default WTP Fallback value is enabled (1). The default WTP Fallback value is enabled (1).
4.8. WTP Saved Variables 4.9. WTP Saved Variables
In addition to the values defined in Section 4.7, the following In addition to the values defined in Section 4.8, the following
values SHOULD be saved on the WTP in non-volatile memory. CAPWAP values SHOULD be saved on the WTP in non-volatile memory. CAPWAP
wireless bindings may define additional values that SHOULD be stored wireless bindings MAY define additional values that SHOULD be stored
on the WTP. on the WTP.
4.8.1. AdminRebootCount 4.9.1. AdminRebootCount
The number of times the WTP has rebooted administratively, defined in The number of times the WTP has rebooted administratively, defined in
Section 4.5.47. Section 4.6.48.
4.8.2. FrameEncapType 4.9.2. FrameEncapType
For WTPs that support multiple Frame Encapsulation Types, it is For WTPs that support multiple Frame Encapsulation Types, it is
useful to save the value configured by the AC. The Frame useful to save the value configured by the AC. The Frame
Encapsulation Type is defined in Section 4.5.41. Encapsulation Type is defined in Section 4.6.41.
4.8.3. LastRebootReason 4.9.3. LastRebootReason
The reason why the WTP last rebooted, defined in Section 4.5.47. The reason why the WTP last rebooted, defined in Section 4.6.48.
4.8.4. MacType 4.9.4. MacType
For WTPs that support multiple MAC Types, it is useful to save the For WTPs that support multiple MAC Types, it is useful to save the
value configured by the AC. The MACType is defined in value configured by the AC. The MACType is defined in
Section 4.5.43. Section 4.6.44.
4.8.5. PreferredACs 4.9.5. PreferredACs
The preferred ACs, with the index, defined in Section 4.5.5. The preferred ACs, with the index, defined in Section 4.6.5.
4.8.6. RebootCount 4.9.6. RebootCount
The number of times the WTP has rebooted, defined in Section 4.5.47. The number of times the WTP has rebooted, defined in Section 4.6.48.
4.8.7. Static ACL Table 4.9.7. Static ACL Table
The static ACL table saved on the WTP, as configured by the Add The static ACL table saved on the WTP, as configured by the Add
Static MAC ACL Entry message element, see Section 4.5.9. Static MAC ACL Entry message element, see Section 4.6.9.
4.8.8. Static IP Address 4.9.8. Static IP Address
The static IP Address assigned to the WTP, as configured by the WTP The static IP Address assigned to the WTP, as configured by the WTP
Static IP Address Information message element (see Section 4.5.48). Static IP Address Information message element (see Section 4.6.49).
4.8.9. WTPLinkFailureCount 4.9.9. WTPLinkFailureCount
The number of times the link to the AC has failed, see The number of times the link to the AC has failed, see
Section 4.5.47. Section 4.6.48.
4.8.10. WTPLocation 4.9.10. WTPLocation
The WTP Location, defined in Section 4.5.28. The WTP Location, defined in Section 4.6.28.
4.8.11. WTPName 4.9.11. WTPName
The WTP Name, defined in Section 4.5.44. The WTP Name, defined in Section 4.6.45.
5. CAPWAP Discovery Operations 5. CAPWAP Discovery Operations
The Discovery messages are used by a WTP to determine which ACs are The Discovery messages are used by a WTP to determine which ACs are
available to provide service, and the capabilities and load of the available to provide service, and the capabilities and load of the
ACs. ACs.
5.1. Discovery Request Message 5.1. Discovery Request Message
The Discovery Request message is used by the WTP to automatically The Discovery Request message is used by the WTP to automatically
skipping to change at page 96, line 18 skipping to change at page 93, line 18
The binding specific WTP Radio Information message element (see The binding specific WTP Radio Information message element (see
Section 2.1) is included in the Discovery Request message to Section 2.1) is included in the Discovery Request message to
advertise WTP support for one or more CAPWAP bindings. advertise WTP support for one or more CAPWAP bindings.
The Discovery Request message is sent by the WTP when in the The Discovery Request message is sent by the WTP when in the
Discovery State. The AC does not transmit this message. Discovery State. The AC does not transmit this message.
The following message elements MUST be included in the Discovery The following message elements MUST be included in the Discovery
Request message: Request message:
o Discovery Type, see Section 4.5.20 o Discovery Type, see Section 4.6.20
o WTP Board Data, see Section 4.5.38 o WTP Board Data, see Section 4.6.38
o WTP Descriptor, see Section 4.5.39 o WTP Descriptor, see Section 4.6.39
o WTP Frame Tunnel Mode, see Section 4.5.41 o WTP Frame Tunnel Mode, see Section 4.6.41
o WTP MAC Type, see Section 4.5.43 o WTP MAC Type, see Section 4.6.44
o WTP Radio Information message element(s)that the WTP supports; o WTP Radio Information message element(s)that the WTP supports;
These are defined by the individual link layer CAPWAP Binding These are defined by the individual link layer CAPWAP Binding
Protocols (see Section 2.1). Protocols (see Section 2.1).
5.2. Discovery Response Message 5.2. Discovery Response Message
The Discovery Response message provides a mechanism for an AC to The Discovery Response message provides a mechanism for an AC to
advertise its services to requesting WTPs. advertise its services to requesting WTPs.
skipping to change at page 97, line 13 skipping to change at page 94, line 13
Note that if the WTP joins an AC that does not support a specific Note that if the WTP joins an AC that does not support a specific
CAPWAP binding, service for that binding MUST NOT be provided by the CAPWAP binding, service for that binding MUST NOT be provided by the
WTP. WTP.
The Discovery Response message is sent by the AC when in the Idle The Discovery Response message is sent by the AC when in the Idle
State. The WTP does not transmit this message. State. The WTP does not transmit this message.
The following message elements MUST be included in the Discovery The following message elements MUST be included in the Discovery
Response Message: Response Message:
o AC Descriptor, see Section 4.5.1 o AC Descriptor, see Section 4.6.1
o AC Name, see Section 4.5.4 o AC Name, see Section 4.6.4
o WTP Radio Information message element(s)that the AC supports; o WTP Radio Information message element(s)that the AC supports;
These are defined by the individual link layer CAPWAP Binding These are defined by the individual link layer CAPWAP Binding
Protocols (see Section 2.1 for more information). Protocols (see Section 2.1 for more information).
o One of the following message elements MUST be included in the o One of the following message elements MUST be included in the
Discovery Response Message: Discovery Response Message:
* CAPWAP Control IPv4 Address, see Section 4.5.10 * CAPWAP Control IPv4 Address, see Section 4.6.10
* CAPWAP Control IPv6 Address, see Section 4.5.11 * CAPWAP Control IPv6 Address, see Section 4.6.11
5.3. Primary Discovery Request Message 5.3. Primary Discovery Request Message
The Primary Discovery Request message is sent by the WTP to determine The Primary Discovery Request message is sent by the WTP to determine
whether its preferred (or primary) AC is available. whether its preferred (or primary) AC is available.
A Primary Discovery Request message is sent by a WTP when it has a A Primary Discovery Request message is sent by a WTP when it has a
primary AC configured, and is connected to another AC. This primary AC configured, and is connected to another AC. This
generally occurs as a result of a failover, and is used by the WTP as generally occurs as a result of a failover, and is used by the WTP as
a means to discover when its primary AC becomes available. Since the a means to discover when its primary AC becomes available. Since the
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The frequency of the Primary Discovery Request messages should be no The frequency of the Primary Discovery Request messages should be no
more often than the sending of the Echo Request message. more often than the sending of the Echo Request message.
Upon receipt of a Primary Discovery Request message, the AC responds Upon receipt of a Primary Discovery Request message, the AC responds
with a Primary Discovery Response message sent to the address in the with a Primary Discovery Response message sent to the address in the
source address of the received Primary Discovery Request message. source address of the received Primary Discovery Request message.
The following message elements MUST be included in the Primary The following message elements MUST be included in the Primary
Discovery Request message. Discovery Request message.
o Discovery Type, see Section 4.5.20 o Discovery Type, see Section 4.6.20
o WTP Board Data, see Section 4.5.38 o WTP Board Data, see Section 4.6.38
o WTP Descriptor, see Section 4.5.39 o WTP Descriptor, see Section 4.6.39
o WTP Frame Tunnel Mode, see Section 4.5.41 o WTP Frame Tunnel Mode, see Section 4.6.41
o WTP MAC Type, see Section 4.5.43 o WTP MAC Type, see Section 4.6.44
o WTP Radio Information message element(s)that the WTP supports; o WTP Radio Information message element(s)that the WTP supports;
These are defined by the individual link layer CAPWAP Binding These are defined by the individual link layer CAPWAP Binding
Protocols (see Section 2.1 for more information). Protocols (see Section 2.1 for more information).
5.4. Primary Discovery Response 5.4. Primary Discovery Response
The Primary Discovery Response message enables an AC to advertise its The Primary Discovery Response message enables an AC to advertise its
availability and services to requesting WTPs that are configured to availability and services to requesting WTPs that are configured to
have the AC as its primary AC. have the AC as its primary AC.
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establish a CAPWAP protocol connection to its primary AC, based on establish a CAPWAP protocol connection to its primary AC, based on
the configuration of the WTP Fallback Status message element on the the configuration of the WTP Fallback Status message element on the
WTP. WTP.
The Primary Discovery Response message is sent by the AC when in the The Primary Discovery Response message is sent by the AC when in the
Idle State. The WTP does not transmit this message. Idle State. The WTP does not transmit this message.
The following message elements MUST be included in the Primary The following message elements MUST be included in the Primary
Discovery Response message. Discovery Response message.
o AC Descriptor, see Section 4.5.1 o AC Descriptor, see Section 4.6.1
o AC Name, see Section 4.5.4 o AC Name, see Section 4.6.4
o WTP Radio Information message element(s)that the AC supports; o WTP Radio Information message element(s)that the AC supports;
These are defined by the individual link layer CAPWAP Binding These are defined by the individual link layer CAPWAP Binding
Protocols (see Section 2.1 for more information). Protocols (see Section 2.1 for more information).
One of the following message elements MUST be included in the One of the following message elements MUST be included in the
Discovery Response Message: Discovery Response Message:
o CAPWAP Control IPv4 Address, see Section 4.5.10 o CAPWAP Control IPv4 Address, see Section 4.6.10
o CAPWAP Control IPv6 Address, see Section 4.5.11 o CAPWAP Control IPv6 Address, see Section 4.6.11
6. CAPWAP Join Operations 6. CAPWAP Join Operations
The Join Request message is used by a WTP to request service from an The Join Request message is used by a WTP to request service from an
AC after a DTLS connection is established to that AC. The Join AC after a DTLS connection is established to that AC. The Join
Response message is used by the the AC to indicate that it will or Response message is used by the the AC to indicate that it will or
will not provide service. will not provide service.
6.1. Join Request 6.1. Join Request
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If an invalid (i.e. malformed) Join Request message is received, the If an invalid (i.e. malformed) Join Request message is received, the
message MUST be silently discarded by the AC. No response is sent to message MUST be silently discarded by the AC. No response is sent to
the WTP. The AC SHOULD log this event. the WTP. The AC SHOULD log this event.
The Join Request is sent by the WTP when in the Join State. The AC The Join Request is sent by the WTP when in the Join State. The AC
does not transmit this message. does not transmit this message.
The following message elements MUST be included in the Join Request The following message elements MUST be included in the Join Request
message. message.
o Location Data, see Section 4.5.28 o Location Data, see Section 4.6.28
o WTP Board Data, see Section 4.5.38
o WTP Descriptor, see Section 4.5.39 o WTP Board Data, see Section 4.6.38
o WTP IPv4 IP Address, see Section 4.5.42
o WTP Name, see Section 4.5.44 o WTP Descriptor, see Section 4.6.39
o WTP Name, see Section 4.6.45
o Session ID, see Section 4.5.35 o Session ID, see Section 4.6.35
o WTP Frame Tunnel Mode, see Section 4.5.41 o WTP Frame Tunnel Mode, see Section 4.6.41
o WTP MAC Type, see Section 4.5.43 o WTP MAC Type, see Section 4.6.44
o WTP Radio Information message element(s)that the WTP supports; o WTP Radio Information message element(s)that the WTP supports;
These are defined by the individual link layer CAPWAP Binding These are defined by the individual link layer CAPWAP Binding
Protocols (see Section 2.1 for more information). Protocols (see Section 2.1 for more information).
At least one of the following message element MUST be included in the
Join Request message.
o WTP IPv4 IP Address, see Section 4.6.42
o WTP IPv6 IP Address, see Section 4.6.43
The following message element MAY be included in the Join Request The following message element MAY be included in the Join Request
message. message.
o Maximum Message Length, see Section 4.5.29 o Maximum Message Length, see Section 4.6.29
o WTP Reboot Statistics, see Section 4.5.47 o WTP Reboot Statistics, see Section 4.6.48
o WTP IPv4 IP Address, see Section 4.6.42
o WTP IPv6 IP Address, see Section 4.6.43
6.2. Join Response 6.2. Join Response
The Join Response message is sent by the AC to indicate to a WTP that The Join Response message is sent by the AC to indicate to a WTP that
it is capable and willing to provide service to the WTP. it is capable and willing to provide service to the WTP.
The WTP, receiving a Join Response message, checks for success or The WTP, receiving a Join Response message, checks for success or
failure. If the message indicates success, the WTP clears the failure. If the message indicates success, the WTP clears the
WaitDTLS timer for the session and proceeds to the Configure state. WaitDTLS timer for the session and proceeds to the Configure state.
If the WaitDTLS Timer expires prior to reception of the Join Response If the WaitDTLS Timer expires prior to reception of the Join Response
message, the WTP MUST terminate the handshake, deallocate session message, the WTP MUST terminate the handshake, deallocate session
state and initiate the DTLSAbort command. state and initiate the DTLSAbort command.
If an invalid (malformed) Join Response message is received, the WTP If an invalid (malformed) Join Response message is received, the WTP
SHOULD log an informative message detailing the error. This error SHOULD log an informative message detailing the error. This error
MUST be treated in the same manner as AC non-responsiveness. The MUST be treated in the same manner as AC non-responsiveness. The
WaitDTLS timer will eventually expire, and the WTP may (if it is so WaitDTLS timer will eventually expire, and the WTP MAY (if it is so
configured) attempts to join a new AC. configured) attempts to join a new AC.
If one of the WTP Radio Information message elements (see If one of the WTP Radio Information message elements (see
Section 2.1) in the Join Request message requested support for a Section 2.1) in the Join Request message requested support for a
CAPWAP binding which the AC does not support, the AC sets the Result CAPWAP binding which the AC does not support, the AC sets the Result
Code message element to "Binding Not Supported". Code message element to "Binding Not Supported".
The AC includes the Image Identifier message element to indicate the The AC includes the Image Identifier message element to indicate the
software version it expects the WTP to run. This information is used software version it expects the WTP to run. This information is used
to determine whether the WTP MUST either change its currently running to determine whether the WTP MUST either change its currently running
firmware image, or download a new version (see Section 9.1.1). firmware image, or download a new version (see Section 9.1.1).
The Join Response message is sent by the AC when in the Join State. The Join Response message is sent by the AC when in the Join State.
The WTP does not transmit this message. The WTP does not transmit this message.
The following message elements MAY be included in the Join Response The following message elements MAY be included in the Join Response
message. message.
o AC IPv4 List, see Section 4.5.2 o AC IPv4 List, see Section 4.6.2
o AC IPv6 List, see Section 4.5.3 o AC IPv6 List, see Section 4.6.3
o Image Identifier, see Section 4.5.25 o Image Identifier, see Section 4.6.25
o Maximum Message Length, see Section 4.5.29 o Maximum Message Length, see Section 4.6.29
The following message elements MUST be included in the Join Response The following message elements MUST be included in the Join Response
message. message.
o Result Code, see Section 4.5.33 o Result Code, see Section 4.6.33
o AC Descriptor, see Section 4.5.1 o AC Descriptor, see Section 4.6.1
o AC Name, see Section 4.5.4 o AC Name, see Section 4.6.4
o WTP Radio Information message element(s)that the AC supports; o WTP Radio Information message element(s)that the AC supports;
These are defined by the individual link layer CAPWAP Binding These are defined by the individual link layer CAPWAP Binding
Protocols (see Section 2.1). Protocols (see Section 2.1).
One of the following message elements MUST be included in the One of the following message elements MUST be included in the
Discovery Response Message: Discovery Response Message:
o CAPWAP Control IPv4 Address, see Section 4.5.10 o CAPWAP Control IPv4 Address, see Section 4.6.10
o CAPWAP Control IPv6 Address, see Section 4.5.11 o CAPWAP Control IPv6 Address, see Section 4.6.11
7. Control Channel Management 7. Control Channel Management
The Control Channel Management messages are used by the WTP and AC to The Control Channel Management messages are used by the WTP and AC to
maintain a control communication channel. CAPWAP control messages, maintain a control communication channel. CAPWAP control messages,
such as the WTP Event Request message sent from the WTP to the AC such as the WTP Event Request message sent from the WTP to the AC
indicate to the AC that the WTP is operational. When such control indicate to the AC that the WTP is operational. When such control
messages are not being sent, the Echo Request and Echo Response messages are not being sent, the Echo Request and Echo Response
messages are used to maintain the control communication channel. messages are used to maintain the control communication channel.
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The Configuration Status message includes multiple Radio The Configuration Status message includes multiple Radio
Administrative State message elements, one for the WTP, and one for Administrative State message elements, one for the WTP, and one for
each radio in the WTP. each radio in the WTP.
The Configuration Status message is sent by the WTP when in the The Configuration Status message is sent by the WTP when in the
Configure State. The AC does not transmit this message. Configure State. The AC does not transmit this message.
The following message elements MUST be included in the Configuration The following message elements MUST be included in the Configuration
Status message. Status message.
o AC Name, see Section 4.5.4 o AC Name, see Section 4.6.4
o AC Name with Index, see Section 4.5.5 o AC Name with Index, see Section 4.6.5
o Radio Administrative State, see Section 4.5.31 o Radio Administrative State, see Section 4.6.31
o Statistics Timer, see Section 4.5.36 o Statistics Timer, see Section 4.6.36
o WTP Reboot Statistics, see Section 4.5.47 o WTP Reboot Statistics, see Section 4.6.48
The following message elements MAY be included in the Configuration The following message elements MAY be included in the Configuration
Status message. Status message.
o WTP Static IP Address Information, see Section 4.5.48 o WTP Static IP Address Information, see Section 4.6.49
8.3. Configuration Status Response 8.3. Configuration Status Response
The Configuration Status Response message is sent by an AC and The Configuration Status Response message is sent by an AC and
provides a mechanism for the AC to override a WTP's requested provides a mechanism for the AC to override a WTP's requested
configuration. configuration.
A Configuration Status Response message is sent by an AC after A Configuration Status Response message is sent by an AC after
receiving a Configuration Request message. receiving a Configuration Request message.
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State message element that causes a change in the operational state State message element that causes a change in the operational state
of one of the radios, the WTP transmits a Change State Event to the of one of the radios, the WTP transmits a Change State Event to the
AC, as an acknowledgement of the change in state. AC, as an acknowledgement of the change in state.
The Configuration Status Response message is sent by the AC when in The Configuration Status Response message is sent by the AC when in
the Configure State. The WTP does not transmit this message. the Configure State. The WTP does not transmit this message.
The following message elements MUST be included in the Configuration The following message elements MUST be included in the Configuration
Status Response message. Status Response message.
o AC IPv4 List, see Section 4.5.2 o AC IPv4 List, see Section 4.6.2
o AC IPv6 List, see Section 4.5.3 o AC IPv6 List, see Section 4.6.3
o CAPWAP Timers, see Section 4.5.12 o CAPWAP Timers, see Section 4.6.12
o Decryption Error Report Period, see Section 4.5.16 o Decryption Error Report Period, see Section 4.6.16
o Idle Timeout, see Section 4.5.23 o Idle Timeout, see Section 4.6.23
o WTP Fallback, see Section 4.5.40 o WTP Fallback, see Section 4.6.40
The following message element MAY be included in the Configuration The following message element MAY be included in the Configuration
Status Response message. Status Response message.
o WTP Static IP Address Information, see Section 4.5.48 o WTP Static IP Address Information, see Section 4.6.49
8.4. Configuration Update Request 8.4. Configuration Update Request
Configuration Update Request messages are sent by the AC to provision Configuration Update Request messages are sent by the AC to provision
the WTP while in the Run state. This is used to modify the the WTP while in the Run state. This is used to modify the
configuration of the WTP while it is operational. configuration of the WTP while it is operational.
When a WTP receives a Configuration Update Request message, it When a WTP receives a Configuration Update Request message, it
responds with a Configuration Update Response message, with a Result responds with a Configuration Update Response message, with a Result
Code message element indicating the result of the configuration Code message element indicating the result of the configuration
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state. The WTP MAY proceed to download the requested firmware if it state. The WTP MAY proceed to download the requested firmware if it
determines the version specified in the Image Identifier message determines the version specified in the Image Identifier message
element is not in its non-volatile storage (see Section 9.1.1). element is not in its non-volatile storage (see Section 9.1.1).
The Configuration Update Request is sent by the AC when in the Run The Configuration Update Request is sent by the AC when in the Run
State. The WTP does not transmit this message. State. The WTP does not transmit this message.
One or more of the following message elements MAY be included in the One or more of the following message elements MAY be included in the
Configuration Update message. Configuration Update message.
o AC Name with Index, see Section 4.5.5 o AC Name with Index, see Section 4.6.5
o AC Timestamp, see Section 4.5.6 o AC Timestamp, see Section 4.6.6
o Add MAC ACL Entry, see Section 4.5.7 o Add MAC ACL Entry, see Section 4.6.7
o Add Static MAC ACL Entry, see Section 4.5.9 o Add Static MAC ACL Entry, see Section 4.6.9
o CAPWAP Timers, see Section 4.5.12 o CAPWAP Timers, see Section 4.6.12
o Decryption Error Report Period, see Section 4.5.16 o Decryption Error Report Period, see Section 4.6.16
o Delete MAC ACL Entry, see Section 4.5.17 o Delete MAC ACL Entry, see Section 4.6.17
o Delete Static MAC ACL Entry, see Section 4.5.19 o Delete Static MAC ACL Entry, see Section 4.6.19
o Idle Timeout, see Section 4.5.23 o Idle Timeout, see Section 4.6.23
o Location Data, see Section 4.5.28 o Location Data, see Section 4.6.28
o Radio Administrative State, see Section 4.5.31 o Radio Administrative State, see Section 4.6.31
o Statistics Timer, see Section 4.5.36 o Statistics Timer, see Section 4.6.36
o WTP Fallback, see Section 4.5.40 o WTP Fallback, see Section 4.6.40
o WTP Name, see Section 4.5.44 o WTP Name, see Section 4.6.45
o WTP Static IP Address Information, see Section 4.5.48 o WTP Static IP Address Information, see Section 4.6.49
o Image Identifier, see Section 4.5.25 o Image Identifier, see Section 4.6.25
o Initiate Download, see Section 4.5.27 o Initiate Download, see Section 4.6.27
8.5. Configuration Update Response 8.5. Configuration Update Response
The Configuration Update Response message is the acknowledgement The Configuration Update Response message is the acknowledgement
message for the Configuration Update Request message. message for the Configuration Update Request message.
The Configuration Update Response message is sent by a WTP after The Configuration Update Response message is sent by a WTP after
receiving a Configuration Update Request message. receiving a Configuration Update Request message.
When an AC receives a Configuration Update Response message the When an AC receives a Configuration Update Response message the
result code indicates if the WTP successfully accepted the result code indicates if the WTP successfully accepted the
configuration. configuration.
The Configuration Update Response message is sent by the WTP when in The Configuration Update Response message is sent by the WTP when in
the Run State. The AC does not transmit this message. the Run State. The AC does not transmit this message.
The following message element MUST be present in the Configuration The following message element MUST be present in the Configuration
Update message. Update message.
Result Code, see Section 4.5.33 Result Code, see Section 4.6.33
The following message elements MAY be present in the Configuration The following message elements MAY be present in the Configuration
Update Response message. Update Response message.
o Radio Operational State, see Section 4.5.32 o Radio Operational State, see Section 4.6.32
8.6. Change State Event Request 8.6. Change State Event Request
The Change State Event Request message is used by the WTP for two The Change State Event Request message is used by the WTP for two
main purposes: main purposes:
o When sent by the WTP following the reception of a Configuration o When sent by the WTP following the reception of a Configuration
Status Response message from the AC, the WTP uses the Change State Status Response message from the AC, the WTP uses the Change State
Event Request message to provide an update on the WTP radio's Event Request message to provide an update on the WTP radio's
operational state and to confirm that the configuration provided operational state and to confirm that the configuration provided
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service to the WTP if it receives an error, based on local policy, service to the WTP if it receives an error, based on local policy,
and to transition to the Reset state. and to transition to the Reset state.
The Change State Event Request message is sent by a WTP to The Change State Event Request message is sent by a WTP to
acknowledge or report an error condition to the AC for a requested acknowledge or report an error condition to the AC for a requested
configuration in the Configuration Status Response message. The configuration in the Configuration Status Response message. The
Change State Event Request message includes the Result Code message Change State Event Request message includes the Result Code message
element, which indicates whether the configuration was successfully element, which indicates whether the configuration was successfully
applied. If the WTP is unable to apply a specfic configuration applied. If the WTP is unable to apply a specfic configuration
request, it indicates the failure by including one or more Returned request, it indicates the failure by including one or more Returned
Message Element message elements (see Section 4.5.34). Message Element message elements (see Section 4.6.34).
The Change State Event Request message is sent by the WTP in the The Change State Event Request message is sent by the WTP in the
Configure or Run State. The AC does not transmit this message. Configure or Run State. The AC does not transmit this message.
The WTP MAY save its configuration to persistent storage prior to The WTP MAY save its configuration to persistent storage prior to
transmitting the response. However, this is implementation specific transmitting the response. However, this is implementation specific
and is not required. and is not required.
The following message elements MUST be present in the Change State The following message elements MUST be present in the Change State
Event Request message. Event Request message.
o Radio Operational State, see Section 4.5.32 o Radio Operational State, see Section 4.6.32
o Result Code, see Section 4.5.33 o Result Code, see Section 4.6.33
One or more of the following message elements MAY be present in the One or more of the following message elements MAY be present in the
Change State Event Request message. Change State Event Request message.
o Returned Message Element(s), see Section 4.5.34 o Returned Message Element(s), see Section 4.6.34
8.7. Change State Event Response 8.7. Change State Event Response
The Change State Event Response message acknowledges the Change State The Change State Event Response message acknowledges the Change State
Event Request message. Event Request message.
A Change State Event Response message is sent by an AC in response to A Change State Event Response message is sent by an AC in response to
a Change State Event Request message. a Change State Event Request message.
The Change State Event Response message is sent by the AC when in the The Change State Event Response message is sent by the AC when in the
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The Clear Configuration Response message is sent by the WTP after The Clear Configuration Response message is sent by the WTP after
receiving a Clear Configuration Request message and resetting its receiving a Clear Configuration Request message and resetting its
configuration parameters to the manufacturing default values. configuration parameters to the manufacturing default values.
The Clear Configuration Response is sent by the WTP when in the Run The Clear Configuration Response is sent by the WTP when in the Run
State. The AC does not transmit this message. State. The AC does not transmit this message.
The Clear Configuration Request message MUST include the following The Clear Configuration Request message MUST include the following
message element. message element.
o Result Code, see Section 4.5.33 o Result Code, see Section 4.6.33
9. Device Management Operations 9. Device Management Operations
This section defines CAPWAP operations responsible for debugging, This section defines CAPWAP operations responsible for debugging,
gathering statistics, logging, and firmware management. gathering statistics, logging, and firmware management.
9.1. Firmware Management 9.1. Firmware Management
This section describes the firmware download procedures used by the This section describes the firmware download procedures used by the
CAPWAP protocol. Firmware download can occur during the Image Data CAPWAP protocol. Firmware download can occur during the Image Data
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it begins the transfer process by transmitting an Image Data Request it begins the transfer process by transmitting an Image Data Request
message that includes the Image Data message element. This continues message that includes the Image Data message element. This continues
until the firmware image has been transfered. until the firmware image has been transfered.
The Image Data Request message is sent by the WTP or the AC when in The Image Data Request message is sent by the WTP or the AC when in
the Image Data or Run State. the Image Data or Run State.
The following message elements MAY be included in the Image Data The following message elements MAY be included in the Image Data
Request message. Request message.
o Image Data, see Section 4.5.24 o Image Data, see Section 4.6.24
o Image Identifier, see Section 4.5.25 o Image Identifier, see Section 4.6.25
9.1.2. Image Data Response 9.1.2. Image Data Response
The Image Data Response message acknowledges the Image Data Request The Image Data Response message acknowledges the Image Data Request
message. message.
An Image Data Response message is sent in response to a received An Image Data Response message is sent in response to a received
Image Data Request message. Its purpose is to acknowledge the Image Data Request message. Its purpose is to acknowledge the
receipt of the Image Data Request message. The Result Code is receipt of the Image Data Request message. The Result Code is
included to indicate whether a previously sent Image Data Request included to indicate whether a previously sent Image Data Request
message was invalid. message was invalid.
The Image Data Response message is sent by the WTP or the AC when in The Image Data Response message is sent by the WTP or the AC when in
the Image Data or Run State. the Image Data or Run State.
The following message element MUST be included in the Image Data The following message element MUST be included in the Image Data
Response message. Response message.
o Result Code, see Section 4.5.33 o Result Code, see Section 4.6.33
The following message elements MAY be included in the Image Data The following message elements MAY be included in the Image Data
Response message. Response message.
o Image Information, see Section 4.5.26 o Image Information, see Section 4.6.26
o Initiate Download, see Section 4.5.27 o Initiate Download, see Section 4.6.27
Upon receiving an Image Data Response message indicating an error, Upon receiving an Image Data Response message indicating an error,
the WTP MAY retransmit a previous Image Data Reqest message, or the WTP MAY retransmit a previous Image Data Reqest message, or
abandon the firmware download to the WTP by transitioning to the abandon the firmware download to the WTP by transitioning to the
Reset state. Reset state.
9.2. Reset Request 9.2. Reset Request
The Reset Request message is used to cause a WTP to reboot. The Reset Request message is used to cause a WTP to reboot.
A Reset Request message is sent by an AC to cause a WTP to A Reset Request message is sent by an AC to cause a WTP to
reinitialize its operation. reinitialize its operation.
The Reset Request is sent by the AC when in the Run State. The WTP The Reset Request is sent by the AC when in the Run State. The WTP
does not transmit this message. does not transmit this message.
The following message elements MUST be included in the Reset Request The following message elements MUST be included in the Reset Request
message. message.
o Image Identifier, see Section 4.5.25 o Image Identifier, see Section 4.6.25
When a WTP receives a Reset Request message, it responds with a Reset When a WTP receives a Reset Request message, it responds with a Reset
Response message indicating success and then reinitialize itself. If Response message indicating success and then reinitialize itself. If
the WTP is unable to write to its non-volatile storage, to ensure the WTP is unable to write to its non-volatile storage, to ensure
that it runs the requested software version indicated in the Image that it runs the requested software version indicated in the Image
Identifier message element, it MAY send the appropriate Result Code Identifier message element, it MAY send the appropriate Result Code
message element, but MUST reboot. If the WTP is unable to reset, message element, but MUST reboot. If the WTP is unable to reset,
including a hardware reset, it sends a Reset Response message to the including a hardware reset, it sends a Reset Response message to the
AC with a Result Code message element indicating failure. The AC no AC with a Result Code message element indicating failure. The AC no
longer provides service to the WTP. longer provides service to the WTP.
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A Reset Response message is sent by the WTP after receiving a Reset A Reset Response message is sent by the WTP after receiving a Reset
Request message. Request message.
The Reset Response is sent by the WTP when in the Run State. The AC The Reset Response is sent by the WTP when in the Run State. The AC
does not transmit this message. does not transmit this message.
The following message element MAY be included in the Image Data The following message element MAY be included in the Image Data
Request message. Request message.
o Result Code, see Section 4.5.33 o Result Code, see Section 4.6.33
When an AC receives a successful Reset Response message, it is When an AC receives a successful Reset Response message, it is
notified that the WTP will reinitialize its operation. An AC that notified that the WTP will reinitialize its operation. An AC that
receives a Reset Response message indicating failure may opt to no receives a Reset Response message indicating failure may opt to no
longer provide service to the WTP. longer provide service to the WTP.
9.4. WTP Event Request 9.4. WTP Event Request
The WTP Event Request message is used by a WTP to send information to The WTP Event Request message is used by a WTP to send information to
its AC. The WTP Event Request message may be sent periodically, or its AC. The WTP Event Request message MAY be sent periodically, or
sent in response to an asynchronous event on the WTP. For example, a sent in response to an asynchronous event on the WTP. For example, a
WTP MAY collect statistics and use the WTP Event Request message to WTP MAY collect statistics and use the WTP Event Request message to
transmit the statistics to the AC. transmit the statistics to the AC.
When an AC receives a WTP Event Request message it will respond with When an AC receives a WTP Event Request message it will respond with
a WTP Event Response message. a WTP Event Response message.
The presence of the Delete Station message element is used by the WTP The presence of the Delete Station message element is used by the WTP
to inform the AC that it is no longer providing service to the to inform the AC that it is no longer providing service to the
station. This could be the result of an Idle Timeout (see station. This could be the result of an Idle Timeout (see
Section 4.5.23), due to to resource shortages, or some other reason. Section 4.6.23), due to to resource shortages, or some other reason.
The WTP Event Request message is sent by the WTP when in the Run The WTP Event Request message is sent by the WTP when in the Run
State. The AC does not transmit this message. State. The AC does not transmit this message.
The WTP Event Request message MUST contain one of the message The WTP Event Request message MUST contain one of the message
elements listed below, or a message element that is defined for a elements listed below, or a message element that is defined for a
specific wireless technology. More than one of each messsage element specific wireless technology. More than one of each messsage element
listed may be included in the WTP Event Request message. listed MAY be included in the WTP Event Request message.
o Decryption Error Report, see Section 4.5.15 o Decryption Error Report, see Section 4.6.15
o Duplicate IPv4 Address, see Section 4.5.21 o Duplicate IPv4 Address, see Section 4.6.21
o Duplicate IPv6 Address, see Section 4.5.22 o Duplicate IPv6 Address, see Section 4.6.22
o WTP Operational Statistics, see Section 4.5.45 o WTP Operational Statistics, see Section 4.6.46
o WTP Radio Statistics, see Section 4.5.46 o WTP Radio Statistics, see Section 4.6.47
o WTP Reboot Statistics, see Section 4.5.47 o WTP Reboot Statistics, see Section 4.6.48
o Delete Station, see Section 4.5.18 o Delete Station, see Section 4.6.18
9.5. WTP Event Response 9.5. WTP Event Response
The WTP Event Response message acknowledges receipt of the WTP Event The WTP Event Response message acknowledges receipt of the WTP Event
Request message. Request message.
A WTP Event Response message is sent by an AC after receiving a WTP A WTP Event Response message is sent by an AC after receiving a WTP
Event Request message. Event Request message.
The WTP Event Response message is sent by the AC when in the Run The WTP Event Response message is sent by the AC when in the Run
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When the AC receives a Data Transfer Request message it responds to When the AC receives a Data Transfer Request message it responds to
the WTP with a Data Transfer Response message. The AC MAY log the the WTP with a Data Transfer Response message. The AC MAY log the
information received. information received.
The Data Transfer Request message is sent by the WTP when in the Run The Data Transfer Request message is sent by the WTP when in the Run
State. The AC does not transmit this message. State. The AC does not transmit this message.
The Data Transfer Request message MUST contain one of the message The Data Transfer Request message MUST contain one of the message
elements listed below. elements listed below.
o Data Transfer Data, see Section 4.5.13 o Data Transfer Data, see Section 4.6.13
o Data Transfer Mode, see Section 4.5.14 o Data Transfer Mode, see Section 4.6.14
9.7. Data Transfer Response 9.7. Data Transfer Response
The Data Transfer Response message acknowledges the Data Transfer The Data Transfer Response message acknowledges the Data Transfer
Request message. Request message.
A Data Transfer Response message is sent in response to a received A Data Transfer Response message is sent in response to a received
Data Transfer Request message. Its purpose is to acknowledge receipt Data Transfer Request message. Its purpose is to acknowledge receipt
of the Data Transfer Request message. of the Data Transfer Request message.
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10. Station Session Management 10. Station Session Management
Messages in this section are used by the AC to create, modify or Messages in this section are used by the AC to create, modify or
delete station session state on the WTPs. delete station session state on the WTPs.
10.1. Station Configuration Request 10.1. Station Configuration Request
The Station Configuration Request message is used to create, modify The Station Configuration Request message is used to create, modify
or delete station session state on a WTP. The message is sent by the or delete station session state on a WTP. The message is sent by the
AC to the WTP, and may contain one or more message elements. The AC to the WTP, and MAY contain one or more message elements. The
message elements for this CAPWAP control message include information message elements for this CAPWAP control message include information
that is generally highly technology specific. Refer to the that is generally highly technology specific. Refer to the
appropriate binding document for definitions of the messages elements appropriate binding document for definitions of the messages elements
that are included in this control message. that are included in this control message.
The Station Configuration Request message is sent by the AC when in The Station Configuration Request message is sent by the AC when in
the Run State. The WTP does not transmit this message. the Run State. The WTP does not transmit this message.
The following CAPWAP Control message elements MAY be included in the The following CAPWAP Control message elements MAY be included in the
Station Configuration Request message. More than one of each message Station Configuration Request message. More than one of each message
element listed may be included in the Station Configuration Request element listed MAY be included in the Station Configuration Request
message. message.
o Add Station, see Section 4.5.8 o Add Station, see Section 4.6.8
o Delete Station, see Section 4.5.18 o Delete Station, see Section 4.6.18
10.2. Station Configuration Response 10.2. Station Configuration Response
The Station Configuration Response message is used to acknowledge a The Station Configuration Response message is used to acknowledge a
previously received Station Configuration Request message. previously received Station Configuration Request message.
The Station Configuration Response message is sent by the WTP when in The Station Configuration Response message is sent by the WTP when in
the Run State. The AC does not transmit this message. the Run State. The AC does not transmit this message.
The following message element MUST be present in the Station The following message element MUST be present in the Station
Configuration Response message. Configuration Response message.
o Result Code, see Section 4.5.33 o Result Code, see Section 4.6.33
The Result Code message element indicates that the requested The Result Code message element indicates that the requested
configuration was successfully applied, or that an error related to configuration was successfully applied, or that an error related to
processing of the Station Configuration Request message occurred on processing of the Station Configuration Request message occurred on
the WTP. the WTP.
11. NAT Considerations 11. NAT Considerations
There are three specific situations in which a NAT deployment may be There are three specific situations in which a NAT deployment may be
used in conjunction with a CAPWAP-enabled deployment. The first used in conjunction with a CAPWAP-enabled deployment. The first
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3. Require that if a WTP determines that the AC List message element 3. Require that if a WTP determines that the AC List message element
contains a set of IP Addresses that are different from the AC IP contains a set of IP Addresses that are different from the AC IP
Address the WTP is currently using, then assume that NAT is Address the WTP is currently using, then assume that NAT is
present, and require that the WTP communicate with the AC IP present, and require that the WTP communicate with the AC IP
Address (and ignore the CAPWAP Control IP (v4/v6) Address message Address (and ignore the CAPWAP Control IP (v4/v6) Address message
element(s)). element(s)).
The CAPWAP protocol allows for all of the AC identities supporting a The CAPWAP protocol allows for all of the AC identities supporting a
group of WTPs to be communicated through the AC List message element. group of WTPs to be communicated through the AC List message element.
This feature must be disabled when the AC is behind a NAT and the IP This feature MUST be disabled when the AC is behind a NAT and the IP
Address that is embedded is invalid. Address that is embedded is invalid.
The CAPWAP protocol allows an AC to configure a static IP address on The CAPWAP protocol allows an AC to configure a static IP address on
a WTP using the WTP Static IP Address Information message element. a WTP using the WTP Static IP Address Information message element.
This message element SHOULD NOT be used in NAT'ed environments, This message element SHOULD NOT be used in NAT'ed environments,
unless the administrator is familiar with the internal IP addressing unless the administrator is familiar with the internal IP addressing
scheme within the WTP's private network, and does not rely on the scheme within the WTP's private network, and does not rely on the
public address seen by the AC. public address seen by the AC.
When a WTP detects the duplicate address condition, it generates a When a WTP detects the duplicate address condition, it generates a
message to the AC, which includes the Duplicate IP Address message message to the AC, which includes the Duplicate IP Address message
element. The IP Address embedded within this message element is element. The IP Address embedded within this message element is
different from the public IP address seen by the AC. different from the public IP address seen by the AC.
When CAPWAP is run over IPv6, NAT support can only be provided if the When CAPWAP is run over IPv6, NAT support can only be provided if the
IPv6 NAT system is capable of performing address translation over the IPv6 NAT system is capable of performing address translation over the
UDP-Lite 3828 protocol [13]. A protocol interoperability issues will UDP-Lite 3828 protocol [11]. A protocol interoperability issues will
exist if the NAT system is being utilized for IPv4/IPv6 address exist if the NAT system is being utilized for IPv4/IPv6 address
translation. translation.
12. Security Considerations 12. Security Considerations
This section describes security considerations for the CAPWAP This section describes security considerations for the CAPWAP
protocol. It also provides security recommendations for protocols protocol. It also provides security recommendations for protocols
used in conjunction with CAPWAP. used in conjunction with CAPWAP.
12.1. CAPWAP Security 12.1. CAPWAP Security
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o When DTLS is used with a preshared-key (PSK) ciphersuite, each WTP o When DTLS is used with a preshared-key (PSK) ciphersuite, each WTP
SHOULD have a unique PSK. Since WTPs will likely be widely SHOULD have a unique PSK. Since WTPs will likely be widely
deployed, their physical security is not guaranteed. If PSKs are deployed, their physical security is not guaranteed. If PSKs are
not unique for each WTP, key reuse would allow the compromise of not unique for each WTP, key reuse would allow the compromise of
one WTP to result in the compromise of others one WTP to result in the compromise of others
o Generating PSKs from low entropy passwords is NOT RECOMMENDED. o Generating PSKs from low entropy passwords is NOT RECOMMENDED.
o It is RECOMMENDED that implementations that allow the o It is RECOMMENDED that implementations that allow the
administrator to manually configure the PSK also provide a administrator to manually configure the PSK also provide a
capability for generation of new random PSKs, taking RFC 1750 [2] capability for generation of new random PSKs, taking RFC 4086 [2]
into account. into account.
o Preshared keys SHOULD be periodically updated. Implementations o Preshared keys SHOULD be periodically updated. Implementations
may facilitate this by providing an administrative interface for MAY facilitate this by providing an administrative interface for
automatic key generation and periodic update, or it may be automatic key generation and periodic update, or it MAY be
accomplished manually instead. accomplished manually instead.
Every pairwise combination of WTP and AC on the network SHOULD have a Every pairwise combination of WTP and AC on the network SHOULD have a
unqiue PSK. This prevents the domino effect (see Guidance for AAA unqiue PSK. This prevents the domino effect (see Guidance for AAA
Key Management [15]). If PSKs are tied to specific WTPs, then Key Management [16]). If PSKs are tied to specific WTPs, then
knowledge of the PSK implies a binding to a specified identity that knowledge of the PSK implies a binding to a specified identity that
can be authorized. can be authorized.
If PSKs are shared, this binding between device and identity is no If PSKs are shared, this binding between device and identity is no
longer possible. Compromise of one WTP can yield compromise of longer possible. Compromise of one WTP can yield compromise of
another WTP, violating the CAPWAP security hierarchy. Consequently, another WTP, violating the CAPWAP security hierarchy. Consequently,
sharing keys between WTPs is NOT RECOMMENDED. sharing keys between WTPs is NOT RECOMMENDED.
12.6. Use of Certificates in CAPWAP 12.6. Use of Certificates in CAPWAP
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protocol MAY be used for the purposes of monitoring the WTP directly, protocol MAY be used for the purposes of monitoring the WTP directly,
configuring the WTP through a separate management interface is not configuring the WTP through a separate management interface is not
recommended. Configuring the WTP through a separate protocol, such recommended. Configuring the WTP through a separate protocol, such
as via a CLI or SNMP, could lead to the AC state being out of sync as via a CLI or SNMP, could lead to the AC state being out of sync
with the WTP. with the WTP.
14. IANA Considerations 14. IANA Considerations
A separate UDP port for data channel communications is (currently) A separate UDP port for data channel communications is (currently)
the selected demultiplexing mechanism, and a port must be assigned the selected demultiplexing mechanism, and a port must be assigned
for this purpose in section Section 3.1. The UDP port numbers are for this purpose in Section 3.1. The UDP port numbers are listed by
listed by IANA at http://www.iana.org/assignments/port-numbers. IANA at http://www.iana.org/assignments/port-numbers.
IANA needs to assign a DHCP code point, currently identified as TBD
in the Section 3.3. DHCP options are defined in RFC 1533 [10], and
are listed by IANA at
http://www.iana.org/assignments/bootp-dhcp-parameters.
IANA needs to assign an organization local multicast address called IANA needs to assign an organization local multicast address called
the "All ACs multicast address" from the IPv6 multicast address the "All ACs multicast address" from the IPv6 multicast address
registry in Section 3.3 registry in Section 3.3
14.1. CAPWAP Message Types 14.1. CAPWAP Message Types
The Message Type field in the CAPWAP header (Section 4.4.1.1) is used The Message Type field in the CAPWAP header (Section 4.5.1.1) is used
to identify the operation performed by the message. There are to identify the operation performed by the message. There are
multiple namespaces, which is identified via the first three octets multiple namespaces, which is identified via the first three octets
of the field containing the IANA Enterprise Number [12]. When the of the field containing the IANA Enterprise Number [10]. When the
Enterprise Number is set to zero, the message types are reserved for Enterprise Number is set to zero, the message types are reserved for
use by the base CAPWAP specification which are controlled and use by the base CAPWAP specification which are controlled and
maintained by IANA. maintained by IANA and requires a Standards Action.
14.2. Wireless Binding Identifiers
The Wireless Binding Identifier (WBID) field in the CAPWAP header
(Section 4.3) is used to identify the wireless technology associated
with the packet. Due to the limited address space available, a new
WBID request requires Standards Action.
15. Acknowledgements 15. Acknowledgements
The following individuals are acknowledged for their contributions to The following individuals are acknowledged for their contributions to
this protocol specification: Puneet Agarwal, Saravanan Govindan, this protocol specification: Puneet Agarwal, Saravanan Govindan,
Peter Nilsson, and David Perkins. Peter Nilsson, and David Perkins.
Michael Vakulenko contributed text to describe how CAPWAP can be used Michael Vakulenko contributed text to describe how CAPWAP can be used
over layer 3 (IP/UDP) networks. over layer 3 (IP/UDP) networks.
16. References 16. References
16.1. Normative References 16.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[2] Eastlake, D., Crocker, S., and J. Schiller, "Randomness [2] Eastlake, D., Schiller, J., and S. Crocker, "Randomness
Recommendations for Security", RFC 1750, December 1994. Requirements for Security", BCP 106, RFC 4086, June 2005.
[3] Mills, D., "Network Time Protocol (Version 3) Specification, [3] Mills, D., "Network Time Protocol (Version 3) Specification,
Implementation", RFC 1305, March 1992. Implementation", RFC 1305, March 1992.
[4] Housley, R., Polk, W., Ford, W., and D. Solo, "Internet X.509 [4] Housley, R., Polk, W., Ford, W., and D. Solo, "Internet X.509
Public Key Infrastructure Certificate and Certificate Public Key Infrastructure Certificate and Certificate
Revocation List (CRL) Profile", RFC 3280, April 2002. Revocation List (CRL) Profile", RFC 3280, April 2002.
[5] Aboba, B. and J. Wood, "Authentication, Authorization and [5] Aboba, B. and J. Wood, "Authentication, Authorization and
Accounting (AAA) Transport Profile", RFC 3539, June 2003. Accounting (AAA) Transport Profile", RFC 3539, June 2003.
[6] Eronen, P. and H. Tschofenig, "Pre-Shared Key Ciphersuites for [6] Eronen, P. and H. Tschofenig, "Pre-Shared Key Ciphersuites for
Transport Layer Security (TLS)", RFC 4279, December 2005. Transport Layer Security (TLS)", RFC 4279, December 2005.
[7] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) [7] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS)
Protocol Version 1.1", RFC 4346, April 2006. Protocol Version 1.1", RFC 4346, April 2006.
[8] Manner, J. and M. Kojo, "Mobility Related Terminology", [8] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
RFC 3753, June 2004.
[9] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security", RFC 4347, April 2006. Security", RFC 4347, April 2006.
[10] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor [9] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
Extensions", RFC 1533, October 1993. Extensions", RFC 2132, March 1997.
[11] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0",
RFC 2246, January 1999.
[12] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA [10] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", BCP 26, RFC 2434, Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998. October 1998.
[13] Larzon, L-A., Degermark, M., Pink, S., Jonsson, L-E., and G. [11] Larzon, L-A., Degermark, M., Pink, S., Jonsson, L-E., and G.
Fairhurst, "The Lightweight User Datagram Protocol (UDP-Lite)", Fairhurst, "The Lightweight User Datagram Protocol (UDP-Lite)",
RFC 3828, July 2004. RFC 3828, July 2004.
16.2. Informational References [12] Calhoun, P., Montemurro, M., Stanley, D., "CAPWAP Protocol
Binding for IEEE 802.11", draft-ietf-capwap-protocol-
[14] "draft-ietf-capwap-protocol-binding-specification-ieee802dot11- binding-ieee80211-04 (work in progress), June 2007.
02".
16.3. Informational References [13] Calhoun, P., "CAPWAP Access Controller DHCP Option",
draft-ietf-capwap-dhc-ac-option-00 (work in progress),
June 2007.
[15] "draft-housley-aaa-key-mgmt-06". 16.2. Informational References
[16] Reynolds, J., "Assigned Numbers: RFC 1700 is Replaced by an On- [14] Reynolds, J., "Assigned Numbers: RFC 1700 is Replaced by an On-
line Database", RFC 3232, January 2002. line Database", RFC 3232, January 2002.
[15] Manner, J. and M. Kojo, "Mobility Related Terminology",
RFC 3753, June 2004.
[16] Housley, R. and B. Aboba, "Guidance for AAA Key Management",
draft-housley-aaa-key-mgmt-09 (work in progress),
February 2007.
[17] Modadugu et al, N., "The Design and Implementation of Datagram [17] Modadugu et al, N., "The Design and Implementation of Datagram
TLS", Feb 2004. TLS", Feb 2004.
[18] IEEE, "Guidelines for use of a 48-bit Extended Unique [18] IEEE, "Guidelines for use of a 48-bit Extended Unique
Identifier", Dec 2005. Identifier", Dec 2005.
[19] IEEE, "GUIDELINES FOR 64-BIT GLOBAL IDENTIFIER (EUI-64) [19] IEEE, "GUIDELINES FOR 64-BIT GLOBAL IDENTIFIER (EUI-64)
REGISTRATION AUTHORITY". REGISTRATION AUTHORITY".
Editors' Addresses Editors' Addresses
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