draft-ietf-capwap-protocol-specification-03.txt   draft-ietf-capwap-protocol-specification-04.txt 
Network Working Group P. Calhoun, Editor Network Working Group P. Calhoun, Editor
Internet-Draft Cisco Systems, Inc. Internet-Draft Cisco Systems, Inc.
Intended status: Informational M. Montemurro, Editor Expires: July 27, 2007 M. Montemurro, Editor
Expires: April 16, 2007 Research In Motion Research In Motion
D. Stanley, Editor D. Stanley, Editor
Aruba Networks Aruba Networks
October 13, 2006 January 23, 2007
CAPWAP Protocol Specification CAPWAP Protocol Specification
draft-ietf-capwap-protocol-specification-03 draft-ietf-capwap-protocol-specification-04
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Copyright (C) The Internet Society (2006). 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 [11]. 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 Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 6 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1. Goals . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.1. Goals . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.2. Conventions used in this document . . . . . . . . . . . . 7 1.2. Conventions used in this document . . . . . . . . . . . . 7
1.3. Contributing Authors . . . . . . . . . . . . . . . . . . 8 1.3. Contributing Authors . . . . . . . . . . . . . . . . . . 8
1.4. Acknowledgements . . . . . . . . . . . . . . . . . . . . 9 1.4. Acknowledgements . . . . . . . . . . . . . . . . . . . . 9
1.5. Terminology . . . . . . . . . . . . . . . . . . . . . . . 9 1.5. Terminology . . . . . . . . . . . . . . . . . . . . . . . 9
2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 10 2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 10
2.1. Wireless Binding Definition . . . . . . . . . . . . . . . 11 2.1. Wireless Binding Definition . . . . . . . . . . . . . . . 11
2.2. CAPWAP Session Establishment Overview . . . . . . . . . . 11 2.2. CAPWAP Session Establishment Overview . . . . . . . . . . 11
2.3. CAPWAP State Machine Definition . . . . . . . . . . . . . 13 2.3. CAPWAP State Machine Definition . . . . . . . . . . . . . 13
2.3.1. CAPWAP Protocol State Transitions . . . . . . . . . . 15 2.3.1. CAPWAP Protocol State Transitions . . . . . . . . . . 15
2.3.2. CAPWAP to DTLS Commands . . . . . . . . . . . . . . . 21 2.3.2. CAPWAP/DTLS Interface . . . . . . . . . . . . . . . . 24
2.3.3. DTLS to CAPWAP Notifications . . . . . . . . . . . . 21 2.4. Use of DTLS in the CAPWAP Protocol . . . . . . . . . . . 26
2.3.4. DTLS State Transitions . . . . . . . . . . . . . . . 22
2.4. Use of DTLS in the CAPWAP Protocol . . . . . . . . . . . 25
2.4.1. DTLS Handshake Processing . . . . . . . . . . . . . . 26 2.4.1. DTLS Handshake Processing . . . . . . . . . . . . . . 26
2.4.2. DTLS Error Handling . . . . . . . . . . . . . . . . . 27 2.4.2. DTLS Session Establishment . . . . . . . . . . . . . 28
2.4.3. DTLS Rehandshake Behavior . . . . . . . . . . . . . . 28 2.4.3. DTLS Error Handling . . . . . . . . . . . . . . . . . 28
2.4.4. DTLS EndPoint Authentication . . . . . . . . . . . . 31 2.4.4. DTLS EndPoint Authentication . . . . . . . . . . . . 29
3. CAPWAP Transport . . . . . . . . . . . . . . . . . . . . . . 34 3. CAPWAP Transport . . . . . . . . . . . . . . . . . . . . . . 33
3.1. UDP Transport . . . . . . . . . . . . . . . . . . . . . . 34 3.1. UDP Transport . . . . . . . . . . . . . . . . . . . . . . 33
3.2. AC Discovery . . . . . . . . . . . . . . . . . . . . . . 34 3.2. AC Discovery . . . . . . . . . . . . . . . . . . . . . . 33
3.3. Fragmentation/Reassembly . . . . . . . . . . . . . . . . 35 3.3. Fragmentation/Reassembly . . . . . . . . . . . . . . . . 34
4. CAPWAP Packet Formats . . . . . . . . . . . . . . . . . . . . 36 4. CAPWAP Packet Formats . . . . . . . . . . . . . . . . . . . . 35
4.1. CAPWAP Header . . . . . . . . . . . . . . . . . . . . . . 37 4.1. CAPWAP preamble . . . . . . . . . . . . . . . . . . . . . 37
4.2. CAPWAP Data Messages . . . . . . . . . . . . . . . . . . 40 4.2. CAPWAP Header . . . . . . . . . . . . . . . . . . . . . . 37
4.3. CAPWAP Control Messages . . . . . . . . . . . . . . . . . 41 4.3. CAPWAP Data Messages . . . . . . . . . . . . . . . . . . 41
4.3.1. Control Message Format . . . . . . . . . . . . . . . 41 4.3.1. CAPWAP Data Keepalive . . . . . . . . . . . . . . . . 41
4.3.2. Control Message Quality of Service . . . . . . . . . 44 4.3.2. Station Data Payloads . . . . . . . . . . . . . . . . 42
4.4. CAPWAP Protocol Message Elements . . . . . . . . . . . . 44 4.4. CAPWAP Control Messages . . . . . . . . . . . . . . . . . 43
4.4.1. AC Descriptor . . . . . . . . . . . . . . . . . . . . 47 4.4.1. Control Message Format . . . . . . . . . . . . . . . 43
4.4.2. AC IPv4 List . . . . . . . . . . . . . . . . . . . . 48 4.4.2. Control Message Quality of Service . . . . . . . . . 46
4.4.3. AC IPv6 List . . . . . . . . . . . . . . . . . . . . 49 4.5. CAPWAP Protocol Message Elements . . . . . . . . . . . . 46
4.4.4. AC Name . . . . . . . . . . . . . . . . . . . . . . . 49 4.5.1. AC Descriptor . . . . . . . . . . . . . . . . . . . . 49
4.4.5. AC Name with Index . . . . . . . . . . . . . . . . . 50 4.5.2. AC IPv4 List . . . . . . . . . . . . . . . . . . . . 50
4.4.6. AC Timestamp . . . . . . . . . . . . . . . . . . . . 50 4.5.3. AC IPv6 List . . . . . . . . . . . . . . . . . . . . 51
4.4.7. Add MAC ACL Entry . . . . . . . . . . . . . . . . . . 50 4.5.4. AC Name . . . . . . . . . . . . . . . . . . . . . . . 51
4.4.8. Add Station . . . . . . . . . . . . . . . . . . . . . 51 4.5.5. AC Name with Index . . . . . . . . . . . . . . . . . 52
4.4.9. Add Static MAC ACL Entry . . . . . . . . . . . . . . 52 4.5.6. AC Timestamp . . . . . . . . . . . . . . . . . . . . 52
4.4.10. CAPWAP Control IPv4 Address . . . . . . . . . . . . . 52 4.5.7. Add MAC ACL Entry . . . . . . . . . . . . . . . . . . 53
4.4.11. CAPWAP Control IPv6 Address . . . . . . . . . . . . . 53 4.5.8. Add Station . . . . . . . . . . . . . . . . . . . . . 53
4.4.12. CAPWAP Timers . . . . . . . . . . . . . . . . . . . . 54 4.5.9. Add Static MAC ACL Entry . . . . . . . . . . . . . . 54
4.4.13. Data Transfer Data . . . . . . . . . . . . . . . . . 54 4.5.10. CAPWAP Control IPv4 Address . . . . . . . . . . . . . 55
4.4.14. Data Transfer Mode . . . . . . . . . . . . . . . . . 55 4.5.11. CAPWAP Control IPv6 Address . . . . . . . . . . . . . 55
4.4.15. Decryption Error Report . . . . . . . . . . . . . . . 55 4.5.12. CAPWAP Timers . . . . . . . . . . . . . . . . . . . . 56
4.4.16. Decryption Error Report Period . . . . . . . . . . . 56 4.5.13. Data Transfer Data . . . . . . . . . . . . . . . . . 56
4.4.17. Delete MAC ACL Entry . . . . . . . . . . . . . . . . 56 4.5.14. Data Transfer Mode . . . . . . . . . . . . . . . . . 57
4.4.18. Delete Station . . . . . . . . . . . . . . . . . . . 57 4.5.15. Decryption Error Report . . . . . . . . . . . . . . . 57
4.4.19. Delete Static MAC ACL Entry . . . . . . . . . . . . . 57 4.5.16. Decryption Error Report Period . . . . . . . . . . . 58
4.4.20. Discovery Type . . . . . . . . . . . . . . . . . . . 58 4.5.17. Delete MAC ACL Entry . . . . . . . . . . . . . . . . 58
4.4.21. Duplicate IPv4 Address . . . . . . . . . . . . . . . 58 4.5.18. Delete Station . . . . . . . . . . . . . . . . . . . 59
4.4.22. Duplicate IPv6 Address . . . . . . . . . . . . . . . 59 4.5.19. Delete Static MAC ACL Entry . . . . . . . . . . . . . 59
4.4.23. Idle Timeout . . . . . . . . . . . . . . . . . . . . 60 4.5.20. Discovery Type . . . . . . . . . . . . . . . . . . . 60
4.4.24. Image Data . . . . . . . . . . . . . . . . . . . . . 60 4.5.21. Duplicate IPv4 Address . . . . . . . . . . . . . . . 61
4.4.25. Image Filename . . . . . . . . . . . . . . . . . . . 61 4.5.22. Duplicate IPv6 Address . . . . . . . . . . . . . . . 61
4.4.26. Initiate Download . . . . . . . . . . . . . . . . . . 61 4.5.23. Idle Timeout . . . . . . . . . . . . . . . . . . . . 62
4.4.27. Location Data . . . . . . . . . . . . . . . . . . . . 62 4.5.24. Image Data . . . . . . . . . . . . . . . . . . . . . 63
4.4.28. MTU Discovery Padding . . . . . . . . . . . . . . . . 62 4.5.25. Image Filename . . . . . . . . . . . . . . . . . . . 63
4.4.29. Radio Administrative State . . . . . . . . . . . . . 62 4.5.26. Initiate Download . . . . . . . . . . . . . . . . . . 64
4.4.30. Radio Operational State . . . . . . . . . . . . . . . 63 4.5.27. Location Data . . . . . . . . . . . . . . . . . . . . 64
4.4.31. Result Code . . . . . . . . . . . . . . . . . . . . . 64 4.5.28. MTU Discovery Padding . . . . . . . . . . . . . . . . 65
4.4.32. Session ID . . . . . . . . . . . . . . . . . . . . . 65 4.5.29. Radio Administrative State . . . . . . . . . . . . . 65
4.4.33. Statistics Timer . . . . . . . . . . . . . . . . . . 65 4.5.30. Radio Operational State . . . . . . . . . . . . . . . 66
4.4.34. Vendor Specific Payload . . . . . . . . . . . . . . . 66 4.5.31. Result Code . . . . . . . . . . . . . . . . . . . . . 67
4.4.35. WTP Board Data . . . . . . . . . . . . . . . . . . . 66 4.5.32. Returned Message Element . . . . . . . . . . . . . . 68
4.4.36. WTP Descriptor . . . . . . . . . . . . . . . . . . . 67 4.5.33. Session ID . . . . . . . . . . . . . . . . . . . . . 69
4.4.37. WTP Fallback . . . . . . . . . . . . . . . . . . . . 69 4.5.34. Statistics Timer . . . . . . . . . . . . . . . . . . 69
4.4.38. WTP Frame Tunnel Mode . . . . . . . . . . . . . . . . 70 4.5.35. Vendor Specific Payload . . . . . . . . . . . . . . . 70
4.4.39. WTP IPv4 IP Address . . . . . . . . . . . . . . . . . 71 4.5.36. WTP Board Data . . . . . . . . . . . . . . . . . . . 70
4.4.40. WTP MAC Type . . . . . . . . . . . . . . . . . . . . 71 4.5.37. WTP Descriptor . . . . . . . . . . . . . . . . . . . 71
4.4.41. WTP Name . . . . . . . . . . . . . . . . . . . . . . 72 4.5.38. WTP Fallback . . . . . . . . . . . . . . . . . . . . 73
4.4.42. WTP Operational Statistics . . . . . . . . . . . . . 72 4.5.39. WTP Frame Tunnel Mode . . . . . . . . . . . . . . . . 73
4.4.43. WTP Radio Statistics . . . . . . . . . . . . . . . . 73 4.5.40. WTP IPv4 IP Address . . . . . . . . . . . . . . . . . 74
4.4.44. WTP Reboot Statistics . . . . . . . . . . . . . . . . 74 4.5.41. WTP MAC Type . . . . . . . . . . . . . . . . . . . . 75
4.4.45. WTP Static IP Address Information . . . . . . . . . . 75 4.5.42. WTP Name . . . . . . . . . . . . . . . . . . . . . . 75
4.5. CAPWAP Protocol Timers . . . . . . . . . . . . . . . . . 76 4.5.43. WTP Operational Statistics . . . . . . . . . . . . . 76
4.5.1. DiscoveryInterval . . . . . . . . . . . . . . . . . . 76 4.5.44. WTP Radio Statistics . . . . . . . . . . . . . . . . 76
4.5.2. DTLSRehandshake . . . . . . . . . . . . . . . . . . . 76 4.5.45. WTP Reboot Statistics . . . . . . . . . . . . . . . . 78
4.5.3. DTLSSessionDelete . . . . . . . . . . . . . . . . . . 77 4.5.46. WTP Static IP Address Information . . . . . . . . . . 79
4.5.4. EchoInterval . . . . . . . . . . . . . . . . . . . . 77 4.6. CAPWAP Protocol Timers . . . . . . . . . . . . . . . . . 80
4.5.5. KeyLifetime . . . . . . . . . . . . . . . . . . . . . 77 4.6.1. DataChannelKeepAlive . . . . . . . . . . . . . . . . 80
4.5.6. MaxDiscoveryInterval . . . . . . . . . . . . . . . . 77 4.6.2. DataChannelDeadInterval . . . . . . . . . . . . . . . 80
4.5.7. NeighborDeadInterval . . . . . . . . . . . . . . . . 77 4.6.3. DiscoveryInterval . . . . . . . . . . . . . . . . . . 81
4.5.8. ResponseTimeout . . . . . . . . . . . . . . . . . . . 77 4.6.4. DTLSRehandshake . . . . . . . . . . . . . . . . . . . 81
4.5.9. RetransmitInterval . . . . . . . . . . . . . . . . . 78 4.6.5. DTLSSessionDelete . . . . . . . . . . . . . . . . . . 81
4.5.10. SilentInterval . . . . . . . . . . . . . . . . . . . 78 4.6.6. EchoInterval . . . . . . . . . . . . . . . . . . . . 81
4.5.11. WaitJoin . . . . . . . . . . . . . . . . . . . . . . 78 4.6.7. KeyLifetime . . . . . . . . . . . . . . . . . . . . . 81
4.6. CAPWAP Protocol Variables . . . . . . . . . . . . . . . . 78 4.6.8. MaxDiscoveryInterval . . . . . . . . . . . . . . . . 81
4.6.1. AdminState . . . . . . . . . . . . . . . . . . . . . 78 4.6.9. MaxFailedDTLSSessionRetry . . . . . . . . . . . . . . 82
4.6.2. DiscoveryCount . . . . . . . . . . . . . . . . . . . 78 4.6.10. NeighborDeadInterval . . . . . . . . . . . . . . . . 82
4.6.3. IdleTimeout . . . . . . . . . . . . . . . . . . . . . 78 4.6.11. ResponseTimeout . . . . . . . . . . . . . . . . . . . 82
4.6.4. MaxDiscoveries . . . . . . . . . . . . . . . . . . . 78 4.6.12. RetransmitInterval . . . . . . . . . . . . . . . . . 82
4.6.5. MaxRetransmit . . . . . . . . . . . . . . . . . . . . 79 4.6.13. SilentInterval . . . . . . . . . . . . . . . . . . . 82
4.6.6. ReportInterval . . . . . . . . . . . . . . . . . . . 79 4.6.14. StatisticsTimer . . . . . . . . . . . . . . . . . . . 82
4.6.7. RetransmitCount . . . . . . . . . . . . . . . . . . . 79 4.6.15. WaitDTLS . . . . . . . . . . . . . . . . . . . . . . 82
4.6.8. StatisticsTimer . . . . . . . . . . . . . . . . . . . 79 4.7. CAPWAP Protocol Variables . . . . . . . . . . . . . . . . 83
4.6.9. WTPFallBack . . . . . . . . . . . . . . . . . . . . . 79 4.7.1. AdminState . . . . . . . . . . . . . . . . . . . . . 83
4.7. WTP Saved Variables . . . . . . . . . . . . . . . . . . . 79 4.7.2. DiscoveryCount . . . . . . . . . . . . . . . . . . . 83
4.7.1. AdminRebootCount . . . . . . . . . . . . . . . . . . 79 4.7.3. FailedDTLSSessionCount . . . . . . . . . . . . . . . 83
4.7.2. FrameEncapType . . . . . . . . . . . . . . . . . . . 79 4.7.4. IdleTimeout . . . . . . . . . . . . . . . . . . . . . 83
4.7.3. LastRebootReason . . . . . . . . . . . . . . . . . . 79 4.7.5. MaxDiscoveries . . . . . . . . . . . . . . . . . . . 83
4.7.4. MacType . . . . . . . . . . . . . . . . . . . . . . . 80 4.7.6. MaxRetransmit . . . . . . . . . . . . . . . . . . . . 83
4.7.5. PreferredACs . . . . . . . . . . . . . . . . . . . . 80 4.7.7. ReportInterval . . . . . . . . . . . . . . . . . . . 83
4.7.6. RebootCount . . . . . . . . . . . . . . . . . . . . . 80 4.7.8. RetransmitCount . . . . . . . . . . . . . . . . . . . 84
4.7.7. Static ACL Table . . . . . . . . . . . . . . . . . . 80 4.7.9. WTPFallBack . . . . . . . . . . . . . . . . . . . . . 84
4.7.8. Static IP Address . . . . . . . . . . . . . . . . . . 80 4.8. WTP Saved Variables . . . . . . . . . . . . . . . . . . . 84
4.7.9. WTPLinkFailureCount . . . . . . . . . . . . . . . . . 80 4.8.1. AdminRebootCount . . . . . . . . . . . . . . . . . . 84
4.7.10. WTPLocation . . . . . . . . . . . . . . . . . . . . . 80 4.8.2. FrameEncapType . . . . . . . . . . . . . . . . . . . 84
4.7.11. WTPName . . . . . . . . . . . . . . . . . . . . . . . 80 4.8.3. LastRebootReason . . . . . . . . . . . . . . . . . . 84
5. CAPWAP Discovery Operations . . . . . . . . . . . . . . . . . 81 4.8.4. MacType . . . . . . . . . . . . . . . . . . . . . . . 84
5.1. Discovery Request Message . . . . . . . . . . . . . . . . 81 4.8.5. PreferredACs . . . . . . . . . . . . . . . . . . . . 84
5.2. Discovery Response Message . . . . . . . . . . . . . . . 82 4.8.6. RebootCount . . . . . . . . . . . . . . . . . . . . . 84
5.3. Primary Discovery Request Message . . . . . . . . . . . . 82 4.8.7. Static ACL Table . . . . . . . . . . . . . . . . . . 85
5.4. Primary Discovery Response . . . . . . . . . . . . . . . 83 4.8.8. Static IP Address . . . . . . . . . . . . . . . . . . 85
6. CAPWAP Join Operations . . . . . . . . . . . . . . . . . . . 84 4.8.9. WTPLinkFailureCount . . . . . . . . . . . . . . . . . 85
6.1. Join Request . . . . . . . . . . . . . . . . . . . . . . 84 4.8.10. WTPLocation . . . . . . . . . . . . . . . . . . . . . 85
6.2. Join Response . . . . . . . . . . . . . . . . . . . . . . 84 4.8.11. WTPName . . . . . . . . . . . . . . . . . . . . . . . 85
7. Control Channel Management . . . . . . . . . . . . . . . . . 86 5. CAPWAP Discovery Operations . . . . . . . . . . . . . . . . . 86
7.1. Echo Request . . . . . . . . . . . . . . . . . . . . . . 86 5.1. Discovery Request Message . . . . . . . . . . . . . . . . 86
7.2. Echo Response . . . . . . . . . . . . . . . . . . . . . . 86 5.2. Discovery Response Message . . . . . . . . . . . . . . . 87
8. WTP Configuration Management . . . . . . . . . . . . . . . . 87 5.3. Primary Discovery Request Message . . . . . . . . . . . . 87
8.1. Configuration Consistency . . . . . . . . . . . . . . . . 87 5.4. Primary Discovery Response . . . . . . . . . . . . . . . 88
8.1.1. Configuration Flexibility . . . . . . . . . . . . . . 88 6. CAPWAP Join Operations . . . . . . . . . . . . . . . . . . . 90
8.2. Configuration Status . . . . . . . . . . . . . . . . . . 88 6.1. Join Request . . . . . . . . . . . . . . . . . . . . . . 90
8.3. Configuration Status Response . . . . . . . . . . . . . . 89 6.2. Join Response . . . . . . . . . . . . . . . . . . . . . . 91
8.4. Configuration Update Request . . . . . . . . . . . . . . 89 7. Control Channel Management . . . . . . . . . . . . . . . . . 92
8.5. Configuration Update Response . . . . . . . . . . . . . . 90 7.1. Echo Request . . . . . . . . . . . . . . . . . . . . . . 92
8.6. Change State Event Request . . . . . . . . . . . . . . . 91 7.2. Echo Response . . . . . . . . . . . . . . . . . . . . . . 92
8.7. Change State Event Response . . . . . . . . . . . . . . . 91 8. WTP Configuration Management . . . . . . . . . . . . . . . . 93
8.8. Clear Configuration Request . . . . . . . . . . . . . . . 91 8.1. Configuration Consistency . . . . . . . . . . . . . . . . 93
8.9. Clear Configuration Response . . . . . . . . . . . . . . 92 8.1.1. Configuration Flexibility . . . . . . . . . . . . . . 94
9. Device Management Operations . . . . . . . . . . . . . . . . 93 8.2. Configuration Status . . . . . . . . . . . . . . . . . . 94
9.1. Image Data Request . . . . . . . . . . . . . . . . . . . 93 8.3. Configuration Status Response . . . . . . . . . . . . . . 95
9.2. Image Data Response . . . . . . . . . . . . . . . . . . . 94 8.4. Configuration Status Acknowledge . . . . . . . . . . . . 96
9.3. Reset Request . . . . . . . . . . . . . . . . . . . . . . 94 8.5. Configuration Update Request . . . . . . . . . . . . . . 96
9.4. Reset Response . . . . . . . . . . . . . . . . . . . . . 94 8.6. Configuration Update Response . . . . . . . . . . . . . . 97
9.5. WTP Event Request . . . . . . . . . . . . . . . . . . . . 95 8.7. Change State Event Request . . . . . . . . . . . . . . . 97
9.6. WTP Event Response . . . . . . . . . . . . . . . . . . . 95 8.8. Change State Event Response . . . . . . . . . . . . . . . 98
9.7. Data Transfer Request . . . . . . . . . . . . . . . . . . 95 8.9. Clear Configuration Request . . . . . . . . . . . . . . . 99
9.8. Data Transfer Response . . . . . . . . . . . . . . . . . 96 8.10. Clear Configuration Response . . . . . . . . . . . . . . 99
10. Station Session Management . . . . . . . . . . . . . . . . . 97 9. Device Management Operations . . . . . . . . . . . . . . . . 100
10.1. Station Configuration Request . . . . . . . . . . . . . . 97 9.1. Image Data Request . . . . . . . . . . . . . . . . . . . 100
10.2. Station Configuration Response . . . . . . . . . . . . . 97 9.2. Image Data Response . . . . . . . . . . . . . . . . . . . 101
11. NAT Considerations . . . . . . . . . . . . . . . . . . . . . 98 9.3. Reset Request . . . . . . . . . . . . . . . . . . . . . . 101
12. Security Considerations . . . . . . . . . . . . . . . . . . . 100 9.4. Reset Response . . . . . . . . . . . . . . . . . . . . . 101
12.1. CAPWAP Security . . . . . . . . . . . . . . . . . . . . . 100 9.5. WTP Event Request . . . . . . . . . . . . . . . . . . . . 102
12.1.1. Converting Protected Data into Unprotected Data . . . 101 9.6. WTP Event Response . . . . . . . . . . . . . . . . . . . 102
9.7. Data Transfer Request . . . . . . . . . . . . . . . . . . 103
9.8. Data Transfer Response . . . . . . . . . . . . . . . . . 103
10. Station Session Management . . . . . . . . . . . . . . . . . 104
10.1. Station Configuration Request . . . . . . . . . . . . . . 104
10.2. Station Configuration Response . . . . . . . . . . . . . 104
11. NAT Considerations . . . . . . . . . . . . . . . . . . . . . 105
12. Security Considerations . . . . . . . . . . . . . . . . . . . 107
12.1. CAPWAP Security . . . . . . . . . . . . . . . . . . . . . 107
12.1.1. Converting Protected Data into Unprotected Data . . . 108
12.1.2. Converting Unprotected Data into Protected Data 12.1.2. Converting Unprotected Data into Protected Data
(Insertion) . . . . . . . . . . . . . . . . . . . . . 101 (Insertion) . . . . . . . . . . . . . . . . . . . . . 108
12.1.3. Deletion of Protected Records . . . . . . . . . . . . 101 12.1.3. Deletion of Protected Records . . . . . . . . . . . . 108
12.1.4. Insertion of Unprotected Records . . . . . . . . . . 101 12.1.4. Insertion of Unprotected Records . . . . . . . . . . 108
12.2. Use of Preshared Keys in CAPWAP . . . . . . . . . . . . . 101 12.2. Use of Preshared Keys in CAPWAP . . . . . . . . . . . . . 108
12.3. Use of Certificates in CAPWAP . . . . . . . . . . . . . . 102 12.3. Use of Certificates in CAPWAP . . . . . . . . . . . . . . 109
12.4. AAA Security . . . . . . . . . . . . . . . . . . . . . . 103 12.4. AAA Security . . . . . . . . . . . . . . . . . . . . . . 110
13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 104 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 111
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 105 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 112
14.1. Normative References . . . . . . . . . . . . . . . . . . 105 14.1. Normative References . . . . . . . . . . . . . . . . . . 112
14.2. Informational References . . . . . . . . . . . . . . . . 105 14.2. Informational References . . . . . . . . . . . . . . . . 112
Editors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 106 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 114
Intellectual Property and Copyright Statements . . . . . . . . . 107 Intellectual Property and Copyright Statements . . . . . . . . . 115
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 [11] 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
skipping to change at page 9, line 21 skipping to change at page 9, line 21
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
1.4. Acknowledgements 1.4. Acknowledgements
The authors thank Michael Vakulenko for contributing text that The authors thank Michael Vakulenko for contributing text that
describes how CAPWAP can be used over a layer 3 (IP/UDP) network. describes how CAPWAP can be used over a layer 3 (IP/UDP) network.
The authors thank Russ Housley and Charles Clancy for their The authors thank Russ Housley and Charles Clancy for their
assistance in provide a security review of the LWAPP specification. assistance in provide a security review of the LWAPP specification.
Charles' review can be found at [9]. Charles' review can be found at [11].
1.5. Terminology 1.5. Terminology
Access Controller (AC): The network entity that provides WTP 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.
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.
skipping to change at page 11, line 34 skipping to change at page 11, line 34
to configure STA information on the WTP, and a WTP Radio Information to configure STA information on the WTP, and a WTP Radio Information
message element carried in the Discovery Request, Primary Discovery message element carried in the Discovery Request, Primary Discovery
Request and and Join Request messages, indicating the binding Request and and Join Request messages, indicating the binding
specific radio types supported at the WTP. If technology specific specific radio types supported at the WTP. If technology specific
message elements are required for any of the existing CAPWAP messages message elements are required for any of the existing CAPWAP messages
defined in this specification, they MUST also be defined in the defined in this specification, they MUST also be defined in the
technology binding document. 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 [11], begins with "IEEE 802.11"." provided in [12], begins with "IEEE 802.11"."
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.
============ ============ ============ ============
skipping to change at page 13, line 22 skipping to change at page 13, line 22
Section 2.3 provides a detailed description of the corresponding Section 2.3 provides a detailed description of the corresponding
state machine. state machine.
2.3. CAPWAP State Machine Definition 2.3. CAPWAP State Machine Definition
The following state diagram represents the lifecycle of a WTP-AC The following state diagram represents the lifecycle of a WTP-AC
session. Use of DTLS by the CAPWAP protocol results in the session. Use of DTLS by the CAPWAP protocol results in the
juxtaposition of two nominally separate yet tightly bound state juxtaposition of two nominally separate yet tightly bound state
machines. The DTLS and CAPWAP state machines are coupled through an machines. The DTLS and CAPWAP state machines are coupled through an
API consisting of commands (from CAPWAP to DTLS) and notifications API consisting of commands (from CAPWAP to DTLS) and notifications
(from (DTLS to CAPWAP). Certain transitions in the DTLS state (from DTLS to CAPWAP). Certain transitions in the DTLS state machine
machine are triggered by commands from the CAPWAP state machine, are triggered by commands from the CAPWAP state machine, while
while certain transitions in the CAPWAP state machine are triggered certain transitions in the CAPWAP state machine are triggered by
by notifications from the DTLS state machine. notifications from the DTLS state machine.
This section defines the CAPWAP Integrated State Machine. In the
figure below, single lines (denoted with '-' and '|') are used to
illustrate state transitions. Double lines (denoted with '=' and
'"') are used to illustrate commands and notifications between DTLS
and CAPWAP. A line composed of '~' characters is used to delineate
the boundary between nominal CAPWAP and DTLS state machine
components.
/-------------<----------------+--------------------\ /-------------------------\
v |d | w| |
+------+ b+-----------+ +----------+ | 5+----------+ x +------------+ |
| Idle |-->| Discovery |--->| Sulking | | | Run |-->| Reset |-\|
+------+ a +-----------+ c +----------+ | +----------+ +------------+ ||
^ |aa ^ |e /----------------------\ | u ^ ^ ^ y||
| V f| v k| | | +------------+--------/ | | ||
h +--------------+ +------------+ i +------------+j | | | Data Check | /-------/ | ||
/--| Join |->| Configure |-->| Image Data | | | +------------+<-------\ | | ||
| +--------------+ g+------------+ +------------+ | | t| s| 4 o| ||
| "c1, ^ ^ ^ m| ^ |l | | +--------+ +-----------+ +------------+ ||
| "c4 " " " | /-------/ | /----/ | | Join |---->| Configure |---->| Image Data | ||
| " " " " V |s v V | +--------+ q +-----------+ r +------------+ ||
| " " " " +------------+ o+------------+ | ^ p| ||
| " " " " | Run |->| Reset |-------/ | \------------------------------------\ ||
| " " " " n+------------+ +------------+ p \---------------------\ | ||
| " " " " "c2 ^ ^ c3" ^ /--------------<----------------+---------------\ | ||
\---"-----"--"---"--------"----"-------/ " " CAPWAP | /------------<-------------\ | | | ||
~~~~~~~"~~~~~"~~"~~~"~~~~~~~~"~~~~"~~~~~~~~~~~~"~~~"~~~~~~~~~~~~ | | m| |n z| v vv
" " " " " " " " DTLS | | +----------------+ +--------------+ +-----------+
v " "n2 \"""""\ " " v "n6,n7 | | | DTLS Setup | | DTLS Connect | | DTLS TD |
/-->+------+ " W+------+ " " " +------------+ | | +----------------+ +--------------+ +-----------+
| /-| Idle | " C| Auth |--"~-"----"----->| Shutdown |-------\P | | g| ^ ^ |h ^ ^
| | +------+ " +------+V " " " /--->| |<----\ | v v | | | | | |
| |X Z| " ^ U| " " n4 " | +------------+ | | | | | | | \-------\ | /-----------/
| | | " | | " " n5," | ^ | | | | | | | | | |
| | v "n1 |Y | n3" v n8" |R |Q | | | | v |e f| 2 v |j |k
| | +--------+ | +------------+ S+------------+ | | | \->+------+ +------+ +-----------+
| | | Init | \->| Run |<--| Rekey | | | | | Idle |-->| Disc | | Authorize |
| | +--------+ | |-->| | | | \--->+------+ a +------+ +-----------+
| | +------------+T +------------+ | | b| ^ |c
| \---------------------------------------------------------/ | | | /----/
\-------------------------------------------------------------/ v d| |
+---------+ |
| Sulking |<-/
3 +---------+
Figure 3: CAPWAP Integrated State Machine Figure 3: CAPWAP Integrated State Machine
The CAPWAP protocol state machine, depicted above, is used by both The CAPWAP protocol state machine, depicted above, is used by both
the AC and the WTP. In cases where states are not shared (i.e. not the AC and the WTP. In cases where states are not shared (i.e. not
implemented in one or the other of the AC or WTP), this is explicitly implemented in one or the other of the AC or WTP), this is explicitly
called out in the transition descriptions below. For every state called out in the transition descriptions below. For every state
defined, only certain messages are permitted to be sent and received. defined, only certain messages are permitted to be sent and received.
The CAPWAP control messages definitions specify the state(s) in which The CAPWAP control messages definitions specify the state(s) in which
each message is valid. each message is valid.
2.3.1. CAPWAP Protocol State Transitions 2.3.1. CAPWAP Protocol State Transitions
The following text discusses the various state transitions, and the The following text discusses the various state transitions, and the
events that cause them. This section does not discuss interactions events that cause them. This section does not discuss interactions
between DTLS- and CAPWAP-specific states. Those interactions, as between DTLS- and CAPWAP-specific states. Those interactions, as
well as DTLS-specific states and transitions, are discussed in well as DTLS-specific states and transitions, are discussed in
subsequent sections. 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 4.5). The WTP resets the DiscoveryCount counter (see Section 4.6). The WTP resets the DiscoveryCount counter
to zero (0) (see Section 4.6). The WTP also clears all to zero (0) (see Section 4.7). 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 Join (aa): This transition occurs when the WTP presents a Idle to Sulking (b): This transition occurs to force the WTP and AC
DTLS ClientHello message containing a valid cookie to the AC. to enter a quiet period to avoid repeatedly attempting to
establish a connection.
WTP: This transition is a no-op for the WTP. WTP: The WTP enters this state when the FailedDTLSSessionCount
counter reaches MaxFailedDTLSSessionRetry variable (see
Section 4.7). Upon entering this state, the WTP shall start
the SilentInterval timer. While in the Sulking state, all
received CAPWAP and DTLS protocol messages received shall be
ignored.
AC: The AC does not maintain state information until the WTP AC: The AC enters this state with the specific WTP when the
presents a DTLS ClientHello message containing a valid cookie. FailedDTLSSessionCount counter reaches
Upon receipt of a DTLS ClientHello message containing a valid MaxFailedDTLSSessionRetry variable (see Section 4.7). Upon
cookie, the AC creates session state and transitions to the entering this state, the AC shall start the SilentInterval
Join state. timer. While in the Sulking state, all received CAPWAP and
DTLS protocol messages received from the WTP shall be ignored.
Discovery to Discovery (b): 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
has not received a Discovery Response message. For every has not received a Discovery Response message. For every
transition to this event, the WTP increments the DiscoveryCount transition to this event, the WTP increments the DiscoveryCount
counter. See Section 5.1 for more information on how the WTP counter. See Section 5.1 for more information on how the WTP
knows the ACs to which it should transmit the Discovery Request knows the ACs to which it should transmit the Discovery Request
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 and the DiscoveryCount variable is equal to the expires or the DiscoveryCount variable is equal to the
MaxDiscoveries variable (see Section 4.6). Upon entering this MaxDiscoveries variable (see Section 4.7). Upon entering this
state, the WTP shall start the SilentInterval timer. While in state, the WTP shall start the SilentInterval timer. While in
the Sulking state, all received CAPWAP protocol messages the Sulking state, all received CAPWAP protocol messages
received shall be ignored. received shall 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 4.5) expires. Section 4.6) expires. The FailedDTLSSessionCount and
DiscoveryCount counters are reset to zero.
AC: This is a no-op. AC: The AC enters this state when the SilentInterval timer (see
Section 4.6) expires. The FailedDTLSSessionCount and
DiscoveryCount counters are reset to zero.
Discovery to Join (e): This transition occurs when the WTP sends a Sulking to Sulking (3): The Sulking state provides the silent
ClientHello message to the AC, confirming that it wishes to be period, minimizing the possibility for Denial of service attacks.
provided services by the AC.
WTP: The WTP selects the best AC based either on information WTP: All packets received from the AC while in the sulking state
it gathered during the Discovery Phase or on its configuration. are ignored.
It then sends a JoinRequest message to its preferred AC, sets
the WaitJoin timer, and awaits the Join Response Message.
AC: This is a no-op for the AC. AC: All packets receive from the WTP while in the sulking state
are ignored.
Join to Discovery (f): This state transition is used to return the Idle to DTLS Setup (e): This transition occurs to establish a secure
WTP to the Discovery state when an unresponsive AC is encountered. DTLS session with the peer.
WTP: The WTP re-enters the Discovery state when the WaitJoin WTP: The WTP initiates this transition by invoking the DTLSStart
timer expires. command, which starts the DTLS session establishment with the
chosen AC. This decision is performed via local configuration
of the AC.
AC: This is a no-op. AC: The AC initiates this transition by invoking the DTLSListen
command, which informs the DTLS stack that it is willing to
listen for an incoming session. The AC MAY provide optional
qualifiers in the DTLSListen to only accept session requests
from specific WTP.
Discovery to DTLS Setup (f): This transition occurs to establish a
secure DTLS session with the peer.
WTP: The WTP initiates this transition by invoking the DTLSStart
command (see Section 2.3.2.1), which starts the DTLS session
establishment with the chosen AC. The decision of which AC to
connect to is the result of the discovery phase, which is
described in Section 3.2.
AC: The AC initiates this transition by invoking the DTLSListen
command (see Section 2.3.2.1), which informs the DTLS stack
that it is willing to listen for an incoming session. The AC
MAY have maintained state information when it received the
Discovery Request in order to provide optional qualifiers in
the DTLSListen command to only accept session requests from
specific WTP. Note that maintaining state information based on
an unsecured discovery request MAY lead to a Denial of Service
attack. Therefore the AC SHOULD ensure that the state
information is freed after a period, which is implementation
specific.
DTLS Setup to Idle (g): This transition occurs when the DTLS Session
failed to be established.
WTP: The WTP initiates this state transition when it receives a
DTLSEstablishFail notification from DTLS (see Section 2.3.2.2).
This error notification aborts the secure DTLS session
establishment. When this transition occurs, the
FailedDTLSSessionCount counter is incremented.
AC: The WTP initiates this state transition when it receives a
DTLSEstablishFail notification from DTLS (see Section 2.3.2.2).
This error notification means a DTLS session was attempted with
a WTP, but failed. The notification should include information
such as the offending WTP, and the reason for the failure.
When this transition occurs, the FailedDTLSSessionCount counter
is incremented.
DTLS Setup to Authorize (h): This transition occurs an incoming DTLS
session is being established, and the DTLS stack needs
authorization to proceed with the session establishment.
WTP: This state transition occurs when the WTP receives the
DTLSPeerAuthorize notification (see Section 2.3.2.2). Upon
entering this state, the WTP MAY perform an authorization check
against the AC's credentials. The method by which this
authorization is performed is outside the scope of the CAPWAP
specification.
AC: This state transition occurs when the AC receives the
DTLSPeerAuthorize notification (see Section 2.3.2.2). Upon
entering this state, the AC MAY perform an authorization check
against the WTP's credentials. The method by which this
authorization is performed is outside the scope of the CAPWAP
specification.
Authorize to DTLS Connect (j): This transition occurs to notify the
DTLS stack that the session should be established.
WTP: This state transition occurs when the WTP has either opted
to forgo the authorization check of the AC's credentials, or
the credentials were successfully authorized. This is done by
invoking the DTLSAccept DTLS command (see Section 2.3.2.1).
AC: This state transition occurs when the AC has either opted to
forgo the authorization check of the WTP's credentials, or the
credentials were successfully authorized. This is done by
invoking the DTLSAccept DTLS command (see Section 2.3.2.1).
Authorize to DTLS Teardown (k): This transition occurs to notify the
DTLS stack that the session should be aborted.
WTP: This state transition occurs when the WTP was unable to
authorize the AC, via its credentials. The WTP then aborts the
DTLS session, which is done by invoking DTLSAbortSession (see
Section 2.3.2.1).
AC: This state transition occurs when the AC was unable to
authorize the WTP, via its credentials. The AC then aborts the
DTLS session, which is done by invoking DTLSAbortSession (see
Section 2.3.2.1).
DTLS Connect to Idle (m): This transition occurs when the DTLS
Session failed to be established.
WTP: This state transition occurs when the WTP receives the
DTLSAborted notification (see Section 2.3.2.2), indicating that
the DTLS session was not successfully established. When this
notification is received, the FailedDTLSSessionCount counter is
incremented.
AC: This state transition occurs when the AC receives the
DTLSAborted notification (see Section 2.3.2.2), indicating that
the DTLS session was not successfully established. When this
notification is received, the FailedDTLSSessionCount counter is
incremented.
DTLS Connect to Join (n): This transition occurs when the DTLS
Session is successfully established.
WTP: This state transition occurs when the WTP receives the
DTLSEstablished notification (see Section 2.3.2.2), indicating
that the DTLS session was successfully established. When this
notification is received, the FailedDTLSSessionCount counter is
set to zero.
AC: This state transition occurs when the AC receives the
DTLSEstablished notification (see Section 2.3.2.2), indicating
that the DTLS session was successfully established. When this
notification is received, the FailedDTLSSessionCount counter is
set to zero.
Join to DTLS Teardown (p): This transition occurs when the join
process failed.
WTP: This state transition occurs when the WTP receives a Join
Response with a Result Code message element containing an
error. This causes the WTP to initiate the DTLSShutdown
command (see Section 2.3.2.1).
AC: This state transition occurs when the AC transmits a Join
Response with a Result Code message element containing an
error. This causes the WTP to initiate the DTLSShutdown
command (see Section 2.3.2.1).
Join to Configure (g): This state transition is used by the WTP and Join to Configure (g): 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 successfully WTP: The WTP enters the Configure state when it successfully
completes the Join operation. If it determines that its completes the Join operation. If it determines that its
version number and the version number advertised by the AC are version number and the version number advertised by the AC are
compatible, the WTP transmits the Configuration Status message compatible, the WTP transmits the Configuration Status message
(see Section 8.2) to the AC with a snapshot of its current (see Section 8.2) to the AC with a snapshot of its current
configuration. The WTP also starts the ResponseTimeout timer configuration. The WTP also starts the ResponseTimeout timer
(see Section 4.5). If the version numbers are not compatible, (see Section 4.6). If the version numbers are not compatible,
the WTP will immediately transition to Image Data state (see the WTP will immediately transition to Image Data state (see
transition (i)). If the AC determines that a new firmware transition (g)). If the AC determines that a new firmware
image should be installed on the WTP, the AC initiates a image should be installed on the WTP, the AC initiates a
firmware download by sending an Image Data Request Message with firmware download by sending an Image Data Request Message with
an Initiate Download message element to the WTP an Initiate Download message element to the WTP
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. If the AC elements to override the WTP's configuration. If the AC
instead receives the Image Data Request from the WTP, it instead receives the Image Data Request from the WTP, it
immediately transitions to the Image Data state (see transition immediately transitions to the Image Data state (see transition
(i)). (g)).
Join to Reset (h): This state transition occurs when the WaitJoin Configure to Reset (s): This state transition is used to reset the
Timer expires. connection either due to an error during the configuration phase,
or when the WTP determines it needs to reset in order for the new
configuration to take effect.
WTP: The state transition occurs when the WTP WaitJoin timer WTP: The WTP enters the Reset state when it receives a
expires, or upon DTLS negotiation failure. Configuration Status Response indicating an error or when it
determines that a reset of the WTP is required, due to the
characteristics of a new configuration.
AC: Thise state transition occurs when the AC WaitJoin timer AC: The AC transitions to the Reset state when it receives a
expires, or or upon DTLS negotiation failure. Change State Event message from the WTP that contains an error
for which the AC's policy does not permit the WTP providing
service.
Configure to Image Data (i): This state transition is used by the Configure to Image Data (r): This state transition is used by the
WTP and the AC to download executable firmware. WTP and the AC to download executable firmware.
WTP: The WTP enters the Image Data state when it successfully WTP: The WTP enters the Image Data state when it successfully
comletes DTLS session establishment, and determines that its comletes DTLS session establishment, and determines that its
version number and the version number advertised by the AC are version number and the version number advertised by the AC are
different. The WTP transmits the Image Data Request (see different. The WTP transmits the Image Data Request (see
Section 9.1) message requesting that a download of the AC's Section 9.1) message requesting that a download of the AC's
latest firmware be initiated. latest firmware be initiated.
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 9.2) to the WTP, which Image Data Response message (see Section 9.2) to the WTP, which
includes a portion of the firmware. includes a portion of the firmware.
Image Data to Image Data (j): The Image Data state is used by WTP Image Data to Image Data (4): The Image Data state is used by WTP
and the AC during the firmware download phase. and the AC during the firmware download phase.
WTP: The WTP enters the Image Data state when it receives an WTP: The WTP enters the Image Data state when it receives an
Image Data Response message indicating that the AC has more Image Data Response message indicating that the AC has more
data to send. data to send.
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 while already in the Image Data Request message from the WTP while already in the Image
Data state, and it detects that the firmware download has not Data state, and it detects that the firmware download has not
completed. completed.
Configure to Reset (k): This state transition is used to reset the Image Data to Reset (o): This state transition is used to reset the
connection to the AC prior to restarting the WTP with a new
configuration.
WTP: The WTP enters the Reset state when it determines that a
reset of the WTP is required, due to the characteristics of a
new configuration.
AC: The AC transitions to the Reset state when it receives the
DTLSPeerDisconnect (n7) notification.
Image Data to Reset (l): This state transition is used to reset the
DTLS connection prior to restarting the WTP after an image DTLS connection prior to restarting the WTP after an image
download. download.
WTP: When an image download completes, the WTP enters the Reset WTP: When an image download completes, the WTP enters the Reset
state, and terminates the DTLS connection, sending a state. The WTP MAY also transition to this state upon
DTLSShutdown command to the DTLS state machine. receiving an Image Data Response from the AC (see Section 9.2)
indicating a failure.
AC: The AC enters the Reset state upon receipt of a DTLSIdle (n6) AC: The AC enters the Reset state when the image download is
notification. complete, or if an error occurs during the image download
process.
Configure to Run (m): This state transition occurs when the WTP and Configure to Data Check (t): This state transition occurs when the
AC enter their normal state of operation. 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 HeartBeat timer (see Section 4.5), and initializes the HeartBeat timer (see Section 4.6), and
transmits the Change State Event Request message (see transmits the Change State Event Request message (see
Section 8.6). Section 8.7).
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 8.7) from the WTP.
The AC responds with a Change State Event Response (see The AC responds with a Change State Event Response (see
Section 8.7) message. The AC must start the Section 8.8) message. The AC must start the
NeighborDeadInterval timer (see Section 4.5). NeighborDeadInterval timer (see Section 4.6).
Run to Run (n): This is the normal state of operation. Data Check to Run (u): This state transition occurs once the linkage
between the control and data channels has occured, which causes
the WTP and AC to enter their normal state of operation.
WTP: The WTP enters this state when it receives a successful
Change State Event Response from the AC. The WTP initiates the
data channel, which MAY require the establishment of a DTLS
session, starts the DataChannelKeepAlive timer (see
Section 4.6) and transmits a Data Channel Keep Alive (see
Section 4.3.1). The WTP then starts the
DataChannelDeadInterval timer (see Section 4.6).
AC: This state transition occurs when the AC receives the Data
Channel Keep Alive (see Section 4.3.1), whose Session ID
message element matches the one included by the WTP in the Join
Request. Note that if the AC's policy is to require the data
channel to be encrypted, this process would also require the
establishment of the data channel's DTLS session. Upon
receiving the Data Channel Keep Alive, the AC transmits its own
Data Channel Keep Alive.
Run to DTLS Teardown (u): This state transition occurs when an error
has occured in the DTLS stack, causing the DTLS session to be
torndown.
WTP: The WTP enters this state when it receives a one of the
following DTLS notifications: DTLSAborted,
DTLSReassemblyFailure, DTLSDecapFailure or DTLSPeerDisconnect
(see Section 2.3.2.2).
AC: The AC enters this state when it receives a one of the
following DTLS notifications: DTLSAborted,
DTLSReassemblyFailure, DTLSDecapFailure or DTLSPeerDisconnect
(see Section 2.3.2.2).
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 8.5). The WTP MUST respond with
a Configuration Update Response message (see Section 8.5). a Configuration Update Response message (see Section 8.6).
Change State Event: The WTP receives a Change State Event Change State Event: The WTP receives a Change State Event
Response message, or determines that it must initiate a Response message, or determines that it must initiate a
Change State Event Request message, as a result of a failure Change State Event Request message, as a result of a failure
or change in the state of a radio. or change in the state of a radio.
Echo Request: The WTP receives an Echo Request message (see Echo Request: The WTP receives an Echo Request message (see
Section 7.1), to which it MUST respond with an Echo Response Section 7.1), to which it MUST respond with an Echo Response
message(see Section 7.2). message(see Section 7.2).
Clear Config Request: The WTP receives a Clear Configuration Clear Config Request: The WTP receives a Clear Configuration
Request message (see Section 8.8). The WTP MUST reset its Request message (see Section 8.9). The WTP MUST reset its
configuration back to manufacturer defaults. configuration back to manufacturer defaults.
WTP Event: The WTP generates a WTP Event Request message to WTP Event: The WTP generates a WTP Event Request message to
send information to the AC (see Section 9.5). The WTP send information to the AC (see Section 9.5). The WTP
receives a WTP Event Response message from the AC (see receives a WTP Event Response message from the AC (see
Section 9.6). Section 9.6).
Data Transfer: The WTP generates a Data Transfer Request Data Transfer: The WTP generates a Data Transfer Request
message to the AC (see Section 9.7). The WTP receives a message to the AC (see Section 9.7). The WTP receives a
Data Transfer Response message from the AC (see Data Transfer Response message from the AC (see
Section 9.8). Section 9.8).
Station Configuration Request: The WTP receives a Station Station Configuration Request: The WTP receives a Station
Config Request message (see Section 10.1), to which it MUST Config Request message (see Section 10.1), to which it MUST
respond with a Station Config Response message (see respond with a Station Config Response message (see
Section 10.2). Section 10.2).
AC: This is the AC's normal state of operation: AC: This is the AC's normal state of operation:
Configuration Update: The AC sends a Configuration Update Configuration Update: The AC sends a Configuration Update
Request message (see Section 8.4) to the WTP to update its Request message (see Section 8.5) to the WTP to update its
configuration. The AC receives a Configuration Update configuration. The AC receives a Configuration Update
Response message (see Section 8.5) from the WTP. Response message (see Section 8.6) from the WTP.
Change State Event: The AC receives a Change State Event Change State Event: The AC receives a Change State Event
Request message (see Section 8.6), to which it MUST respond Request message (see Section 8.7), to which it MUST respond
with the Change State Event Response message (see with the Change State Event Response message (see
Section 8.7). Section 8.8).
Echo: The AC sends an Echo Request message Section 7.1 or Echo: The AC sends an Echo Request message Section 7.1 or
receives the corresponding Echo Response message, see receives the corresponding Echo Response message, see
Section 7.2 from the WTP. Section 7.2 from the WTP.
Clear Config Response: The AC receives a Clear Configuration Clear Config Response: The AC receives a Clear Configuration
Response message (see Section 8.9). Response message (see Section 8.10).
Station Config: The AC sends a Station Configuration Request Station Config: The AC sends a Station Configuration Request
message (see Section 10.1) or receives the corresponding message (see Section 10.1) or receives the corresponding
Station Configuration Response message (see Section 10.2) Station Configuration Response message (see Section 10.2)
from the WTP. from the WTP.
Data Transfer: The AC receives a Data Transfer Request message Data Transfer: The AC receives a Data Transfer Request message
from the AC (see Section 9.7) and MUST generate a from the AC (see Section 9.7) and MUST generate a
corresponding Data Transfer Response message (see corresponding Data Transfer Response message (see
Section 9.8). Section 9.8).
WTP Event: The AC receives a WTP Event Request message from WTP Event: The AC receives a WTP Event Request message from
the AC (see Section 9.5) and MUST generate a corresponding the AC (see Section 9.5) and MUST generate a corresponding
WTP Event Response message (see Section 9.6). WTP Event Response message (see Section 9.6).
Run to Reset(o): This state transition is used when the AC or WTP Run to Reset (x): This state transition is used when the AC or WTP
wish to tear down the connection. This may occur as part of wish to tear down the connection. This may occur as part of
normal operation, or due to error conditions. normal operation, or due to error conditions.
WTP: The WTP enters the Reset state when it initiates orderly WTP: The WTP enters the Reset state when it receives a Reset
termination of the DTLS connection, or when the underlying Request from the AC.
reliable transport is unable to transmit a message within the
RetransmitInterval timer, see Section 4.5. The WTP also enters
the Reset state upon receiving a DTLS session termination
message (DTLS alert) from the AC. The WTP sends a DTLSShutdown
command to the DTLS state machine.
AC: The AC enters the Idle state when it initiates orderly AC: The AC enters the reset state when it transmits a Reset
termination of the DTLS connection, or when the underlying Request to the WTP.
reliable transport is unable to transmit a message within the
RetransmitInterval timer (see Section 4.5), and the maximum
number of RetransmitCount counter has reached the MaxRetransmit
variable (see Section 4.6). The AC also enters the Reset state
upon receiving a DTLS session termination message from the WTP.
Reset to Idle (p): This state transition occurs when the state Reset to DTLS Teardown (y): This transition occurs when the CAPWAP
machine is restarted following a system restart, an unrecoverable reset is complete to terminate the DTLS session.
error on the AC-WTP connection, or orderly session teardown.
WTP: The WTP clears any state associated with any AC and enters WTP: This state transition occurs when the WTP receives a Reset
the Idle state. Response. This causes the WTP to initiate the DTLSShutdown
command (see Section 2.3.2.1).
AC: The AC clears any state associated with the WTP and enters AC: This state transition occurs when the AC transmits a Reset
the idle state. Response. This causes the WTP to initiate the DTLSShutdown
command (see Section 2.3.2.1).
Run to Image Data (s): This state transition occurs when the AC DTLS Teardown to Idle (z): This transition occurs when the DTLS
transmits an Image Data Request to the WTP, with the Initiate session has been shutdown.
Download message element. The means by which the AC decides to
download firmware is undefined, but could occur through an
administrative action.
WTP: The WTP enters this state when it receives an an Image Data WTP: This state transition occurs when the WTP receives a
Request to the WTP, with the Initiate Download message element. DTLSPeerDisconnect notification (see Section 2.3.2.2).
The WTP responds by transmitting an Image Data Request with the
Image Filename message element included..
AC: This state transition occurs when the AC decides that an WTP AC: This state transition occurs when the AC receives a
is to update its firmware by sending an Image Data Request to DTLSPeerDisconnect notification (see Section 2.3.2.2).
the WTP, with the Initiate Download message element.
2.3.2. CAPWAP to DTLS Commands 2.3.2. CAPWAP/DTLS Interface
This section describes the DTLS Commands used by CAPWAP, as well as
the notifications received from DTLS to the CAPWAP protocol stack.
2.3.2.1. CAPWAP to DTLS Commands
Four commands are defined for the CAPWAP to DTLS API. These Four commands are defined for the CAPWAP to DTLS API. These
"commands" are conceptual, and may be implemented as one or more "commands" are conceptual, and may be implemented as one or more
function calls. This API definition is provided to clarify function calls. This API definition is provided to clarify
interactions between the DTLS and CAPWAP components of the integrated interactions between the DTLS and CAPWAP components of the integrated
CAPWAP state machine. CAPWAP state machine.
Below is a list of the minimal command API: Below is a list of the minimal command API:
o c1: DTLSStart is sent to the DTLS module to cause a DTLS session o DTLSStart is sent to the DTLS module to cause a DTLS session to be
to be established. established. Upon invoking the DTLSStart command, the WaitDTLS
timer is started. The WTP is the only CAPWAP device that
initiates this DTLS command, as the AC does not initiate DTLS
sessions.
o c2: DTLSRehandshake is sent to the DTLS module to cause initiation o DTLSListen is sent to the DTLS module to allow the DTLS to listen
of a rehandshake (DTLS rekey). for incoming DTLS session requests.
o c3: DTLSShutdown is sent to the DTLS module to cause session o DTLSAccept is sent to the DTLS module to allow the DTLS session
teardown. establishment to continue successfully.
o c4: DTLSAbort is sent to the DTLS module to cause session teardown o DTLSAbortSession is sent to the DTLS module to cause the session
when the WaitJoin timer expires. that is in the process of being established, to be aborted. This
command is also sent when the WaitDTLS timer expires. When this
command is executed, the FailedDTLSSessionCount counter is
incremented.
2.3.3. DTLS to CAPWAP Notifications o DTLSShutdown is sent to the DTLS module to cause session teardown.
Eight notifications are defined for the DTLS to CAPWAP API. These 2.3.2.2. DTLS to CAPWAP Notifications
DTLS notifications are defined for the DTLS to CAPWAP API. These
"notifications" are conceptual, and may be implemented in numerous "notifications" are conceptual, and may be implemented in numerous
ways (e.g. as function return values). This API definition is ways (e.g. as function return values). This API definition is
provided to clarify interactions between the DTLS and CAPWAP provided to clarify interactions between the DTLS and CAPWAP
components of the integrated CAPWAP state machine. components of the integrated CAPWAP state machine. It is important
to note that the notifications listed below MAY cause the CAPWAP
state machine to jump from one state to another using a state
transition not listed in section Section 2.3.1. When a notification
listed below occurs, the target CAPWAP state shown in Figure 3
becomes the current state.
Below is a list of the API notifications: Below is a list of the API notifications:
o n1: DTLSInitFailure is sent to the CAPWAP module to indicate an o DTLSIncomingSession is sent to the CAPWAP protocol stack during
initialization failure, which may be due to out of memory or other the DTLS session establishment once the peer's identity has been
internal error condition. received. This notification MAY be used by the CAPWAP protocol
stack in order to authorize the session, based on the peer's
o n2: DTLSAuthenticateFail or DTLSAuthorizeFail is sent to the identity. The authorization process will lead to the CAPWAP
CAPWAP module to indicate peer authentication or authorization protocol stack initiating either the DTLSAccept or
failures, respectively. DTLSAbortSession commands.
o n3: DTLSEstablished is sent to the CAPWAP module to indicate that
that a secure channel now exists.
o n4: DTLSEncapFailure may be sent to CAPWAP to indicate an
encapsulation failure. DTLSDecapFailure may be sent to CAPWAP to
indicate an encryption/authentication failure
o n5: DTLSRehandshake is sent to the CAPWAP module to indicate DTLS
rehandshake initiation by peer.
o n6: DTLSIdle is sent to the CAPWAP module to indicate that session
abort (as requested by CAPWAP) is complete; this occurs when the
WaitJoin timer expires, or when CAPWAP is executing an orderly
session shutdown.
o n7: DTLSPeerDisconnect is sent to the CAPWAP module to indicate
DTLS session teardown by peer. Note that the n7 notification, can
be received while in the Join, Configure, Image Data, Run and
Reset states, and always causes a transition to the Reset state.
o n8: DTLSReassemblyFailure may be sent to the CAPWAP module to
indicate DTLS fragment reassembly failure.
2.3.4. DTLS State Transitions
This section describes the transitions in the DTLS-specific portion
of the state machine.
Idle to Init (Z): This transition indicates the begining of a DTLS
session.
WTP: The state ransition is triggered by receipt of the DTLSStart
command from the CAPWAP state machine, and causes the WTP to
send a DTLS ClientHello to the AC.
AC: The state transition is triggered by receipt of the DTLSStart
command from the CAPWAP state machine. The AC starts the
WaitJoin timer and awaits reception of a DTLS ClientHello
message
Init to Authenticate/Authorize (Y) This transition indicates that
the DTLS handshake is in progress.
WTP: The WTP executes this state transition upon receipt of a
valid ServerHello.
AC: The AC executes this transition upon receipt of a certificate
payload (if configured for public key authentication) or upon
receipt of the ClientKeyExchange payload if configured for
preshared keys.
Init to Idle(X) This state transition occurs upon timeout of the
WaitJoin Timer.
WTP: Upon receiving a DTLSAbort command from the CAPWAP state
machine, the WTP DTLS state machine transitions to Idle state.
AC: Upon receiving a DTLSAbort command from the CAPWAP state
machine, the AC DTLS state machine transitions to Idle state.
Authenticate/Authorize to Authenticate/Authorize (W) This state
transition is a Loopback state, representing execution of the TLS
handshake protocol, including authorization callbacks to the
CAPWAP architecture.
WTP: Upon receiving AC credential, attempt to execute associated
validation, authentication, and authorization callbacks. Note
that credentials may span protocol messages, in which case the
WTP will remain in this state pending receipt of all credential
payloads.
AC: Upon receipt of the WTP credential, attempt to execute
associated validation, authentication, and authorization
callbacks. Note that credentials may span protocol messages,
in which case the AC will remain in this state pending receipt
of all credential payloads.
Authenticate/Authorize to Shutdown (V) This state transition
indicates a failure of the DTLS handshake.
WTP: Send a DTLSAuthenticateFail or DTLSAuthorizeFail to the
CAPWAP state machine, depending on the exact cause of the
error. May send a DTLS notification to the AC to indicate
failure.
AC: Send a DTLSAuthenticateFail or DTLSAuthorizeFail to the
CAPWAP state machine, depending on the exact cause of the
error. May send a DTLS Notification to the AC to indicate
failure.
Authenticate/Authorize to Run (U) This state transition occurs upon
successful completion of the DTLS handshake.
WTP: Send a DTLSEstablished notification to the CAPWAP state
machine.
AC: Send a DTLSEstablished notification to the CAPWAP state
machine.
Run to Rekey (T) This state transition occurs when a DTLS
rehandshake is in progress; this is initiated when either (a) the
DTLS state machine receives the DTLSRehandshake command from
CAPWAP, or (b) a DTLS rehandshake message is received from the
peer..
WTP: If CAPWAP issued a DTLSRehandshake command, initiate
rehandshake with the peer; note that control traffic may
continue to flow using existing secure association. If the
rehandshake is initiated by the peer, send a DTLSRehandshake
notification to CAPWAP.
AC: If CAPWAP issued a DTLSRehandshake command, initiate
rehandshake with the peer; note that control traffic may
continue to flow using existing secure association. If the
rehandshake is initiated by the peer, send a DTLSRehandshake
notification to CAPWAP.
Run to Shutdown (S) This state transition indicates a shutdown of
the DTLS channel.
WTP: This state transition occurs when the CAPWAP state machine
sends a DTLSShutdown command, or when the the AC terminates the
DTLS session.
AC: This state transition occurs when CAPWAP state machine sends
a DTLSShutdown command, or when the WTP terminates the DTLS
session.
Rekey to Run (R) This state transition indicates the successful
completion of a DTLS rehandshake.
WTP: This state transition occurs when the WTP receives the DTLS
Finished message from the AC, completing the DTLS re-handshake.
AC: This state transition occurs when the AC sends a DTLS
Finished message to the WTP, completing the DTLS re-handshake.
Rekey to Shutdown (Q) This state transition indicates the failure of o DTLSEstablished is sent to the CAPWAP module to indicate that that
the DTLS rekey operation. a secure channel now exists, using the parameters provided during
the DTLS initialization process. When this notification is
received, the FailedDTLSSessionCount counter is reset to zero.
When this notification is received, the WaitDTLS is stopped.
WTP: This state transition occurs when there is a failure in the o DTLSEstablishFail is sent when the DTLS session establishment has
rehandshake negotiation with the AC. failed, either due to a local error, or due to the peer rejecting
the session establishment. When this notification is received,
the FailedDTLSSessionCount counter is reset to zero. When this
notification is received, the WaitDTLS is stopped.
AC: This state transition occurs when there is a failure in the o DTLSAborted is sent to the CAPWAP module to indicate that session
rehandshake negotiation with the WTP. abort (as requested by CAPWAP) is complete; this occurs to confirm
a DTLS session abort, or when the WaitDTLS timer expires. When
this notification is received, the WaitDTLS is stopped.
Shutdown to Idle (P) This state transition occurs upon transmission o DTLSReassemblyFailure may be sent to the CAPWAP module to indicate
of a DTLS Session termination message, or upon receipt of a DTLS DTLS fragment reassembly failure.
session termination message.
WTP: This state transition occurs after the WTP transmits the o DTLSDecapFailure may be sent to CAPWAP to indicate an
DTLS session termination message. If the WTP receives a DTLS decapsulation failure. DTLSDecapFailure may be sent to CAPWAP to
session termination message, it sends the DTLSPeerDisconnect indicate an encryption/authentication failure.
notification to CAPWAP and moves to the Idle state.
AC: This state transition occurs after the AC transmits the DTLS o DTLSPeerDisconnect is sent to the CAPWAP module to indicate the
session termination message. If the AC receives a DTLS session DTLS session has been torn down. Note that this notification is
termination message, it sends the DTLSPeerDisconnect only received if the DTLS session has been established.
notification to CAPWAP and moves to the Idle state.
2.4. Use of DTLS in the CAPWAP Protocol 2.4. Use of DTLS in the CAPWAP Protocol
DTLS is used as a tightly-integrated, secure wrapper for the CAPWAP DTLS is used as a tightly-integrated, secure wrapper for the CAPWAP
protocol. In this document DTLS and CAPWAP are discussed as protocol. In this document DTLS and CAPWAP are discussed as
nominally distinct entitites; however they are very closely coupled, nominally distinct entitites; however they are very closely coupled,
and may even be implemented inseparably. Since there are DTLS and may even be implemented inseparably. Since there are DTLS
library implementations currently available, and since security library implementations currently available, and since security
protocols (e.g. IPsec, TLS) are often implemented in widely protocols (e.g. IPsec, TLS) are often implemented in widely
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 [DTLS]. This Details of the DTLS handshake process are specified in [9]. This
section describes the interactions between the DTLS session section describes the interactions between the DTLS session
establishment process and the CAPWAP protocol. In the normal case, establishment process and the CAPWAP protocol. Note that the
the DTLS handshake will proceed as follows (NOTE: this example uses conceptual DTLS state is shown below to help understand the point at
which the DTLS states transition. In the normal case, the DTLS
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
============ ============ ============ ============
<DTLS Idle> <DTLS Idle>
ClientHello ------> ClientHello ------>
<------ HelloVerifyRequest <------ HelloVerifyRequest
(with cookie) (with cookie)
<DTLS Setup>
ClientHello ------> ClientHello ------>
(with cookie) (with cookie)
<DTLS Setup>
<------ ServerHello <------ ServerHello
<------ Certificate <------ Certificate
<------ ServerHelloDone <------ ServerHelloDone
(WTP callout for AC authorization) (WTP callout for AC authorization
occurs in CAPWAP Auth state)
<DTLS Run>
Certificate* Certificate*
ClientKeyExchange ClientKeyExchange
CertificateVerify* CertificateVerify*
[ChangeCipherSpec] [ChangeCipherSpec]
Finished ------> Finished ------>
(AC callout for WTP (AC callout for WTP authorization
authorization) occurs in CAPWAP Auth state)
<DTLS Run>
[ChangeCipherSpec] [ChangeCipherSpec]
<------ Finished <------ Finished
DTLS, as specified, provides its own retransmit timers with an DTLS, as specified, provides its own retransmit timers with an
exponential back-off. However, it will never terminate the handshake exponential back-off. However, it will never terminate the handshake
due to non-responsiveness; rather, it will continue to increase its due to non-responsiveness; rather, it will continue to increase its
back-off timer period. Hence, timing out incomplete DTLS handshakes back-off timer period. Hence, timing out incomplete DTLS handshakes
is entirely the responsiblity of the CAPWAP protocol. is entirely the responsiblity of the CAPWAP protocol.
2.4.1.1. Join Operations 2.4.2. DTLS Session Establishment
The WTP, either through the Discovery process, or through pre- The WTP, either through the Discovery process, or through pre-
configuration, determines the AC to connect to. The WTP uses DTLS to configuration, determines the AC to connect to. The WTP uses the
establish a secure connection to the selected AC. Prior to DTLSStart command to request that a secure connection be established
initiation of the DTLS handshake, the WTP sets the WaitJoin timer. to the selected AC. Prior to initiation of the DTLS handshake, the
Upon receipt of a ClientHello message containing a valid cookie, the WTP sets the WaitDTLS timer. Upon receiving the DTLSIncomingSession
AC sets the WaitJoin timer. If the Join operation has not completed DTLS notification, the AC sets the WaitDTLS timer. If the
prior to timer expiration, the Join process is aborted, the WTP DTLSEstablished notification is not received prior to timer
transitions back to Discovery state, and the AC transitions back to expiration, the DTLS session is aborted by issuing the
Idle state. Upon successful completion of the Join process the DTLSAbortSession DTLS command. This notification causes the CAPWAP
WaitJoin timer is deactivated. state to transition back to the Idle state. Upon receiving a
DTLSEstablished notification, the WaitDTLS timer is deactivated.
2.4.2. DTLS Error Handling 2.4.3. DTLS Error Handling
If the AC does not respond to any DTLS messages sent by the WTP, the If the AC does not respond to any DTLS messages sent by the WTP, the
DTLS specification calls for the WTP to retransmit these messages. DTLS specification calls for the WTP to retransmit these messages.
If the WaitJoin timer expires, CAPWAP will issue the DTLSAbort If the WaitDTLS timer expires, CAPWAP will issue the DTLSAbortSession
command, causing DTLS to terminate the handshake and remove any command, causing DTLS to terminate the handshake and remove any
allocated session context. Note that DTLS MAY send a single TLS allocated session context. Note that DTLS MAY send a single TLS
Alert message to the AC to indicate session termination. Alert message to the AC to indicate session termination.
If the WTP does not respond to any DTLS messages sent by the AC, the If the WTP does not respond to any DTLS messages sent by the AC, the
CAPWAP protocol allows for three possiblities, listed below. Note CAPWAP protocol allows for three possiblities, listed below. Note
that DTLS MAY send a single TLS Alert message to the AC to indicate that DTLS MAY send a single TLS Alert message to the AC to indicate
session termination. session termination.
o The message was lost in transit; in this case, the WTP will re- o The message was lost in transit; in this case, the WTP will re-
transmit its last outstanding message, since it did not receive transmit its last outstanding message, since it did not receive
the reply. the reply.
o The WTP sent a DTLS Alert, which was lost in transit; in this o The WTP sent a DTLS Alert, which was lost in transit; in this
case, the AC's WaitJoin timer will expire, and the session will be case, the AC's WaitDTLS timer will expire, and the session will be
terminated. terminated.
o Communication with the WTP has completely failed; in this case, o Communication with the WTP has completely failed; in this case,
the AC's WaitJoin timer will expire, and the session will be the AC's WaitDTLS timer will expire, and the session will be
terminated. terminated.
The DTLS specification provides for retransmission of unacknowledged The DTLS specification provides for retransmission of unacknowledged
requests. If retransmissions remain unacknowledged, the WaitJoin requests. If retransmissions remain unacknowledged, the WaitDTLS
timer will eventually expire, at which time the CAPWAP module will timer will eventually expire, at which time the CAPWAP module will
terminate the session. terminate the session.
If a cookie fails to validate, this could represent a WTP error, or If a cookie fails to validate, this could represent a WTP error, or
it could represent a DoS attack. Hence, AC resource utilization it could represent a DoS attack. Hence, AC resource utilization
SHOULD be minimized. The AC MAY log a message indicating the SHOULD be minimized. The AC MAY log a message indicating the
failure, but SHOULD NOT attempt to reply to the WTP. failure, but SHOULD NOT attempt to reply to the WTP.
Since DTLS handshake messages are potentially larger than the maximum Since DTLS handshake messages are potentially larger than the maximum
record size, DTLS supports fragmenting of handshake messages across record size, DTLS supports fragmenting of handshake messages across
skipping to change at page 28, line 33 skipping to change at page 29, line 38
detected, the packets SHOULD be silently discarded, and the receiver detected, the packets SHOULD be silently discarded, and the receiver
MAY log an error message. MAY log an error message.
There is currently only one encapsulation error defined: MTU There is currently only one encapsulation error defined: MTU
exceeeded. As part of DTLS session establishment, CAPWAP informs exceeeded. As part of DTLS session establishment, CAPWAP informs
DTLS of the MTU size. This may be dynamically modified at any time DTLS of the MTU size. This may be dynamically modified at any time
when CAPWAP sends the DTLSMtuUpdate command to DTLS. DTLS returns when CAPWAP sends the DTLSMtuUpdate command to DTLS. DTLS returns
this notification to CAPWAP whenever a transmission request will this notification to CAPWAP whenever a transmission request will
result in a packet which exceeds the MTU. result in a packet which exceeds the MTU.
2.4.3. DTLS Rehandshake Behavior
DTLS rekeying (known in DTLS as "rehandshake") requires special
attention, as the DTLS specification provides no rehandshake
triggering mechanism. Rather, the application (in this case, CAPWAP)
is expected to manage this for itself. This section addressed
various aspects of rehandshake behavior.
One simple way to think of a DTLS session is as a pair of
unidirectional channels which are tightly bound together. A useful
analogy is the twisted pair used for phone wiring, with one line per
pair. Then, the rehandshake process can be thought of using the call
over the existing pair to establish a call over a new pair - that is,
an entirely new session is negotiated under the protection of the
existing session.
This sounds simple enough, yet there is operational complexity in
changing over to the new session. In particular, how does each end
know when it is safe to delete the "old" session, and switch over to
the new one? If DTLS were not a datagram protocol, this would be
simpler, but the fact that message delivery is unreliable
significantly complicates things: when the AC (the "server")
transmits its Finished message, it cannot be sure that the WTP
received it until the WTP transmits data on the new channel.
This fact constrains the way in which we transition to the new
session, and delete the old one. The WTP, upon receipt of the AC's
Finished message for the new session, immediately makes the new
session active, and transmits no further data (e.g. echo requests,
statistics, etc) on the old channel, and sends a TLS "user_cancelled"
alert message on the old channel, after which the old session is
immediately deleted.
The AC, sets a DTLSSessionDelete timer, (see Section 4.5) and
immediately makes the new session active, and transmits no further
data (e.g. echo requests, statistics, etc) on the old channel.
If a TLS "user_cancelled" alert message is received on the old
channel, the session delete timer is deactivated, and the session is
deleted.
if the dtls-session-delete timer expires, a TLS "user_cancelled"
alert message is transmitted on the old channel, and the session is
deleted.
Note that there is a slight possibility that some packets may be in
flight when the session is deleted. However, since CAPWAP provides
reliable delivery, these packets will be retransmitted over the new
channel.
2.4.3.1. Peer Initiated Rehandshake Triggers
Since key lifetimes are not negotiable in DTLS, it is possible that a
rehandshake from a peer may occur at any time, and implementations
must be prepared for this eventuality. Presumably, communicating
devices will be within the same domain of control. This being the
case, overly-aggressive rekeying may be detected by simply monitoring
logs, assuming such activity is indeed logged. Hence,
implementations MUST log rekey attempts as they occur, reporting the
time and identifying information for the peer.
CAPWAP implementations MUST provide an administrative interface which
permits specification of key lifetimes in seconds. Also,
implementations which wait until this interval has expired to begin
the rehandshake process are liable to encounter temporary service
lapses on heavily loaded networks, so implementations SHOULD begin
the rehandshake before the actual lifetime has elapsed.
Given the relatively low bandwidth we might reasonably expect over a
CAPWAP control channel and the strength of modern cryptographic
algorithms (e.g. AES-128, 3DES, etc), it is reasonable to assume
that lifetimes will typically be more than 8 hours. Given this
assumption, a good rule of thumb for deciding when to rekey is this:
deduct a random number of seconds from the lifetime (say, between 1%
and 5% of the lifetime), and begin the rehandshake process at that
point. Using a random value helps avert collisions, when both sides
initiate a rehandshake at the same time (discussed further below).
2.4.3.2. Time Based Rehandshake Triggers
CAPWAP implementations MUST provide an administrative interface which
permits specification of key lifetimes in seconds. Also,
implementations which wait until this interval has expired to begin
the rehandshake process are liable to encounter temporary service
lapses on heavily loaded networks, so implementations SHOULD begin
the rehandshake before the actual lifetime has elapsed.
Given the relatively low bandwidth we might reasonably expect over a
CAPWAP control channel and the strength of modern cryptographic
algorithms (e.g. AES-128, 3DES, etc), it is reasonable to assume
that key lifetimes will typically be more than 8 hours. Given this
assumption, a good rule of thumb for deciding when to rekey is this:
deduct a random number of seconds from the lifetime (say, between 1%
and 5% of the lifetime), and begin the rehandshake process at that
point. Using a random value helps avert collisions, when both sides
initiate a rehandshake at the same time.
2.4.3.3. Volume Based Rehandshake Triggers
CAPWAP implementations MUST provide an administrative interface which
permits specification of key lifetimes in packet count. Like time-
based, lifetimes, implementations which wait until this interval has
expired to begin the rehandshake process may encounter temporary
service lapses on heavily loaded networks, so implementations SHOULD
begin the rehandshake before the actual lifetime has elapsed.
Volume-based lifetime estimation for purposes of rehandshake
initiation is considerably more complex than time-based lifetime. In
addition to avoiding collisions, the maximum burst rate must be
known, and an extimate made, assuming rehandshake packets are lost,
etc. Hence, we do not specify a one-size-fits-all approach here, and
the specific algorithm used is implementation dependent.
2.4.3.4. Rehandshake Collisions
A collision occurs when both sides initiate a rehandshake
simultaneously. No matter how much care is taken, rehandshake
collisions are a distinct possibility. Hence, a contention
resolution strategy is specified.
A rehandshake collision is detected when a system receives a
rehandshake initiation when it has one outstanding with the same
peer.
When this occurs, each side will compare its own address with that of
its peer (in network byte order).
The one with the lower of the two addresses will ignore the peer's
rehandshake message, and continue with its own rehandshake process.
The one with the higher message will immediately abort its current
rehandshake, and set the DTLSRehandshake timer (see Section 4.5); if
the peer with the lower address does not complete the rehandshake
before the timer expires, the peer with the higher address will re-
initiate.
2.4.4. DTLS EndPoint Authentication 2.4.4. DTLS EndPoint Authentication
DTLS supports endpoint authentication with certificates or preshared DTLS supports endpoint authentication with certificates or preshared
keys. The TLS algorithm suites for each endpoint authentication keys. The TLS algorithm suites for each endpoint authentication
method are described below. method are described below.
2.4.4.1. Authenticating with Certificates 2.4.4.1. Authenticating with Certificates
Note that only block ciphers are currently recommended for use with Note that only block ciphers are currently recommended for use with
DTLS. To understand the reasoning behind this, see [13]. However, DTLS. To understand the reasoning behind this, see [14]. However,
support for AES counter mode encryption is currently progressing in support for AES counter mode encryption is currently progressing in
the TLS working group, and once protocol identifiers are available, the TLS working group, and once protocol identifiers are available,
they will be added below. At present, the following algorithms MUST they will be added below. At present, the following algorithms MUST
be supported when using certificates for CAPWAP authentication: be supported when using certificates for CAPWAP authentication:
o TLS_RSA_WITH_AES_128_CBC_SHA o TLS_RSA_WITH_AES_128_CBC_SHA
o TLS_RSA_WITH_3DES_EDE_CBC_SHA o TLS_RSA_WITH_3DES_EDE_CBC_SHA
The following algorithms SHOULD be supported when using certificates: The following algorithms SHOULD be supported when using certificates:
skipping to change at page 35, line 6 skipping to change at page 34, line 6
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: A comma delimited ASCII encoded list of AC IP addresses is
embedded in the DHCP vendor specific option 43 extension. An embedded in the DHCP code number TBD. An example of the actual
example of the actual format of the vendor specific payload for format of the vendor specific payload for IPv4 is of the form
IPv4 is of the form "10.1.1.1, 10.1.1.2". "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.
3.3. Fragmentation/Reassembly 3.3. 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, Network Address Translation CAPWAP protocol is used involve firewall, Network Address Translation
(NAT) and "middle box" devices, which tend to drop IP fragments in (NAT) and "middle box" devices, which tend to drop IP fragments in
skipping to change at page 36, line 13 skipping to change at page 35, line 13
configurations. configurations.
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 a CAPWAP Transport Layer packet header
followed by a CAPWAP message. The CAPWAP message can be either of followed by a CAPWAP message. The CAPWAP message can be either of
type Control or Data, where Control packets carry signaling, and Data type Control or Data, where Control packets carry signaling, and Data
packets carry user payloads. The CAPWAP frame formats for CAPWAP packets carry user payloads. The CAPWAP frame formats for CAPWAP
Data packets, and for DTLS encapsulated CAPWAP Data and Control Data packets, and for DTLS encapsulated CAPWAP Data and Control
packets. are as shown below: packets. See section Section 3.1 for more information on the use of
UDP.
CAPWAP Data Packet : The CAPWAP Control protocol includes two messages that are never
+--------------------------------+ protected by DTLS. These messages, called the Discovery Request and
| IP |UDP | CAPWAP | Wireless | Discovery Response, need to be in the clear in order for the CAPWAP
| Hdr |Hdr | Header | Payload | protocol to properly identify and process them. The format of these
+--------------------------------+ packets are as follows:
CAPWAP + Optional DTLS Data Packet Security: CAPWAP Control Packet (Discovery Request/Response):
+------------------------------------------------+ +---------------------------------------------------+
| IP |UDP | DTLS | CAPWAP | Wireless | DTLS | | IP | UDP | CAPWAP |CAPWAP | Control | Message |
| Hdr |Hdr | Hdr | Hdr | Payload | Trailer| | Hdr | Hdr | p-amble|Header | Header | Element(s) |
+------------------------------------------------+ +---------------------------------------------------+
\--authenticated-----------/
\--- encrypted-----------/ All other CAPWAP control protocol messages MUST be protected via the
DTLS protocol, which ensures that the packets are both authenticated
and encrypted. The format of these packets are as follows:
CAPWAP Control Packet (DTLS Security Required): CAPWAP Control Packet (DTLS Security Required):
+-----------------------------------------------------------+ +------------------------------------------------------------------+
| IP |UDP | DTLS | CAPWAP | Control | Message | DTLS | | IP | UDP | CAPWAP | DTLS | CAPWAP | Control | Message | DTLS |
| Hdr |Hdr | Hdr | Header | Header | Element(s) | Trailer | | Hdr | Hdr | p-amble| Hdr | Header | Header | Element(s) | Trlr |
+-----------------------------------------------------------+ +------------------------------------------------------------------+
\-------authenticated-----------------/ \----------- authenticated ------------/
\------------encrypted-------------------/ \------------- encrypted -------------/
The CAPWAP protocol allows optional encryption of the data frames,
once again using the DTLS protocol. Whether or not the data frames
are encrypted is a matter of policy, which is described in a later
section of this specification. The format of these packets is as
follows:
CAPWAP Plain Text Data Packet :
+-----------------------------------------+
| IP | UDP | CAPWAP | CAPWAP | Wireless |
| Hdr | Hdr | p-amble| Header | Payload |
+-----------------------------------------+
DTLS Secured CAPWAP Data Packet:
+------------------------------------------------------+
| IP | UDP | CAPWAP | DTLS | CAPWAP | Wireless | DTLS |
| Hdr | Hdr | p-amble| Hdr | Hdr | Payload | Trlr |
+------------------------------------------------------+
\----- authenticated -----/
\------- encrypted --------/
UDP: All CAPWAP packets are encapsulated within UDP. Section UDP: All CAPWAP packets are encapsulated within UDP. Section
Section 3.1 defines the specific UDP usage. Section 3.1 defines the specific UDP usage.
CAPWAP preamble: All CAPWAP protocol packets are prefixed with the
preable header, which is used to identify the frame type that
follows. This header, is defined in Section 4.1.
DTLS Header: The DTLS header provides authentication and encrytion
services to the CAPWAP payload it encapsulates. This protocol is
defined in RFC 4347 [9].
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 UDP header. This header, is defined in immediately follows the UDP header. This header, is defined in
Section 4.1. Section 4.2.
Wireless Payload: A CAPWAP protocol packet that contains a wireless Wireless Payload: A CAPWAP protocol packet that contains a wireless
payload is known as a data frame. The CAPWAP protocol does not payload is known as a data frame. The CAPWAP protocol does not
dictate the format of the wireless payload, which is defined by dictate 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 4.2. Section 4.3.
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 4.3.1. include a Control Header, which is defined in Section 4.4.1.
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 4.4. style header, defined in Section 4.5.
4.1. CAPWAP Header 4.1. CAPWAP preamble
The CAPWAP preamble header is used to help identify the payload type
that immediately follows. The reason for this header to is avoid
needing the perform byte comparisons in order to guess whether the
frame is DTLS encrypted or not. The format of the frame 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Version: A 4 bit field which contains the version of CAPWAP used in
this packet. The value for this draft is zero (0).
Payload Type: A 4 bit field which specifies the payload type that
follows the preamble header. The following values are supported:
0 - Clear text. If the packet is received on the data UDP port,
the CAPWAP stack MUST treat this as a clear text CAPWAP data
packet. If received on the control UDP port, the CAPWAP stack
MUST treat this as a clear text CAPWAP control packet. If the
control packet is not a Discovery Request or Response packet,
it is illegal and MUST be dropped.
1 - DTLS Payload. The packet is either a DTLS packet and MAY be
a data or control packet, based on the UDP port it was received
on (see section Section 3.1).
Reserved: The 24-bit field is reserved for future use. All
implementations complying with this protocol MUST set to zero any
bits that are reserved in the version of the protocol supported by
that implementation. Receivers MUST ignore all bits not defined
for the version of the protocol they support.
4.2. 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.
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| Flags | |Version| RID | HLEN | 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 CAPWAP used in Version: A 4 bit field which contains the version of CAPWAP used in
this packet. The value for this draft is 0. this packet. The value of this field MUST match the version field
set in the CAPWAP preamble header (see Section 4.1). The reason
for this duplicate field is to avoid any possible tampering of the
version field in the preamble header which is not encrypted or
authenticated.
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. WTPs with multiple radios but a single MAC Address range packet. WTPs with multiple radios but a single MAC Address range
use this field to indicate which radio is associated with the use this field to indicate which radio is associated with the
packet. packet.
HLEN: A 5 bit field containing the length of the CAPWAP transport HLEN: A 5 bit field containing the length of the CAPWAP transport
header in 4 byte words (Similar to IP header length). This length header in 4 byte words (Similar to IP header length). This length
includes the optional headers. includes the optional headers.
skipping to change at page 38, line 41 skipping to change at page 39, line 26
W: The Wireless 'W' bit is used to specify whether the optional W: The Wireless 'W' bit is used to specify whether the optional
wireless specific information field is present in the header. A wireless specific information field is present in the header. A
value of one (1) is used to represent the fact that the optional value of one (1) is used to represent the fact that the optional
header is present. header is present.
M: The M bit is used to indicate that the Radio MAC Address optional M: The M bit is used to indicate that the Radio MAC Address optional
header is present. This is used to communicate the MAC address of header is present. This is used to communicate the MAC address of
the receiving radio when the native wireless packet. This field the receiving radio when the native wireless packet. This field
MUST NOT be set to one in packets sent by the AC to the WTP. MUST NOT be set to one in packets sent by the AC to the WTP.
K: The 'Keep-alive' K bit indicates the packet is a data channel
keep-alive packet. This packet is used to map the data channel to
the control channel for the specified Session ID and to maintain
freshness of the Data Channel. The K bit MUST NOT be set for data
packets containing user data.
Flags: A set of reserved bits for future flags in the CAPWAP header. Flags: A set of reserved bits for future flags in the CAPWAP header.
All implementations complying with this protocol MUST set to zero All implementations complying with this protocol MUST set to zero
any bits that are reserved in the version of the protocol any bits that are reserved in the version of the protocol
supported by that implementation. Receivers MUST ignore all bits supported by that implementation. Receivers MUST ignore all bits
not defined for the version of the protocol they support. not defined for the version of the protocol they support.
Fragment ID: An 16 bit field whose value is assigned to each group Fragment ID: An 16 bit field whose value is assigned to each group
of fragments making up a complete set. The fragment ID space is of fragments making up a complete set. The fragment ID space is
managed individually for every WTP/AC pair. The value of Fragment managed individually for every WTP/AC pair. The value of Fragment
ID is incremented with each new set of fragments. The Fragment ID ID is incremented with each new set of fragments. The Fragment ID
skipping to change at page 40, line 14 skipping to change at page 41, line 5
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Wireless ID | Length | Data | Wireless ID | Length | Data
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Wireless ID: The wireless binding identifier. The following Wireless ID: The wireless binding identifier. The following
values are defined: values are defined:
1 - IEEE 802.11 1 - : IEEE 802.11
2 - IEEE 802.16 IEEE 802.16
3 - EPCGlobal EPCGlobal
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 associated with that CAPWAP Control Message, followed by the data associated with that
message. message.
4.2. CAPWAP Data Messages 4.3. CAPWAP Data Messages
There are two different types of CAPWAP data messages; keepalive and
user payload. The first is used by the WTP to synchronize the
control and data channels, as well as to maintain freshness of the
data channel. The second is used to transmit user payloads between
the AC and WTP. This section will detail both types of CAPWAP data
messages.
Both CAPWAP data messages are transmitted on the data channel UDP
port.
4.3.1. CAPWAP Data Keepalive
The CAPWAP data keepalive is used to bind the CAPWAP control channel
with the data channel. The keep alive is also used to maintain
freshness of the data channel, meaning ensuring the channel is still
in functioning. The CAPWAP Data Keepalive is transmitted by the WTP
when the DataChannelKeepAlive timer expires. When the CAPWAP Data
Keepalive is transmitted, the WTP sets the DataChannelDeadInterval
timer.
All of the fields in the CAPWAP header, other than the HLEN and K
bit, are set to zero upon transmission. Upon receiving a CAPWAP Data
Keepalive, the AC transmits a CAPWAP Data Keepalive message back to
the WTP. The contents of the CAPWAP message is assumed to be
identical to the one received.
Upon receiving a CAPWAP Data Keepalive, the WTP cancels the
DataChannelDeadInterval timer and resets the DataChannelKeepAlive
timer. The CAPWAP Data Keepalive is retranmitted by the WTP in the
same manner as the CAPWAP control messages. If the
DataChannelDeadInterval timer expires the WTP tears down the control
DTLS session, as well as the data DTLS session if one existed.
The CAPWAP Data Keepalive contains the following payload immediately
following the CAPWAP Header (see Section 4.2)
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Msg Element Length | Msg Element [0..N] ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message Element Length: The Length field indicates the number of
bytes following the CAPWAP Header.
Message Element[0..N]: The message element(s) carry the information
pertinent to each of the CAPWAP Data Keepalive message. The
following message elements MUST be present in this CAPWAP message:
Session ID, see Section 4.5.33
4.3.2. Station Data Payloads
A CAPWAP protocol data message encapsulates a forwarded wireless A CAPWAP protocol data message encapsulates a forwarded wireless
frame. The CAPWAP protocol defines two different modes of 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 41, line 5 skipping to change at page 43, line 5
subject to the rules defined under the specific wireless technology subject to the rules defined under the specific wireless technology
binding. As a consequence, each wireless technology binding MUST binding. As a consequence, each wireless technology binding MUST
define a section entitled "Payload encapsulation", which defines the define a section entitled "Payload encapsulation", which defines the
format of the wireless payload that is encapsulated within the CAPWAP format of the wireless payload that is encapsulated within the CAPWAP
Data messages. Data messages.
In the event that the encapsulated frame would exceed the transport In the event that the encapsulated frame would exceed the transport
layer's MTU, the sender is responsible for the fragmentation of the layer's MTU, the sender is responsible for the fragmentation of the
frame, as specified in Section 3.3. frame, as specified in Section 3.3.
4.3. CAPWAP Control Messages 4.4. 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
distinct message types: distinct 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 to for a WTP to request service Join: CAPWAP Join messages are used to for a WTP to request service
from an AC, and for the AC to respond to the WTP. from an AC, and for the AC to respond to the WTP.
skipping to change at page 41, line 47 skipping to change at page 43, line 47
Management and Station Session Management CAPWAP control messages Management and Station Session Management CAPWAP control messages
MUST be implemented. Device Operations Management messages MAY be MUST be implemented. Device Operations Management 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.
4.3.1. Control Message Format 4.4.1. 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 4.1). Immediately following the CAPWAP header, header (see Section 4.2). 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Time Stamp |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Msg Element [0..N] ... | Msg Element [0..N] ...
+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+
4.3.1.1. Message Type 4.4.1.1. 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 is the enterprise number in network byte order, with three octets is the enterprise number in network byte order, with
zero being used for CAPWAP generic message types and the IEEE 802.11 zero being used for CAPWAP generic message types and the IEEE 802.11
IANA assigned enterprise number 13277 being used for IEEE 802.11 IANA assigned enterprise number 13277 being 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. The specific message type number, which has a range from 0 to 255. The
message type field can be expressed as: message type field can be expressed as:
skipping to change at page 43, line 13 skipping to change at page 45, line 13
below: below:
CAPWAP Control Message Message Type CAPWAP Control Message Message Type
Value Value
Discovery Request 1 Discovery Request 1
Discovery Response 2 Discovery Response 2
Join Request 3 Join Request 3
Join Response 4 Join Response 4
Configuration Status 5 Configuration Status 5
Configuration Status Response 6 Configuration Status Response 6
Configuration Update Request 7 Configuration Status Acknowledge ???
Configuration Update Response 8
WTP Event Request 9
WTP Event Response 10
Change State Event Request 11
Change State Event Response 12
Echo Request 13
Echo Response 14
Image Data Request 15
Image Data Response 16
Reset Request 17
Reset Response 18
Primary Discovery Request 19
Primary Discovery Response 20
Data Transfer Request 21
Data Transfer Response 22
Clear Configuration Request 23
Clear Configuration Response 24
Station Configuration Request 25
Station Configuration Response 26
4.3.1.2. Sequence Number CAPWAP Control Message Message Type
Value
Discovery Request 1
Discovery Response 2
Join Request 3
Join Response 4
Configuration Status 5
Configuration Status Response 6
Configuration Status Acknowledge ???
4.4.1.2. Sequence Number
The Sequence Number Field is an identifier value to match request and The Sequence Number Field is an identifier value to match request and
response packet exchanges. When a CAPWAP packet with a request response packet exchanges. When a CAPWAP packet with a request
message type is received, the value of the sequence number field is message type is received, the value of the sequence number field is
copied into the corresponding response packet. copied into the corresponding response packet.
When a CAPWAP control message is sent, its internal sequence number When a CAPWAP control message is sent, its internal sequence number
counter is monotonically incremented, ensuring that no two requests counter is monotonically incremented, ensuring that no two requests
pending have the same sequence number. This field will wrap back to pending have the same sequence number. This field will wrap back to
zero. zero.
4.3.1.3. Message Element Length 4.4.1.3. 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
Num field. Number field.
4.3.1.4. Flags 4.4.1.4. Flags
The Flags field MUST be set to zero. The Flags field MUST be set to zero.
4.3.1.5. Time Stamp 4.4.1.5. Message Element[0..N]
The Timestamp contains the timestamp. PRC-TODO: Details need to be
added here, and I am waiting for info from Dave Perkins.
4.3.1.6. 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.
4.3.2. Control Message Quality of Service 4.4.2. 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. CAPWAP Protocol Message Elements 4.5. 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 field, messages. Every message element is identified by the Type field,
whose numbering space is defined below. The total length of the whose numbering space is defined below. The total length of the
message elements is indicated in the Message Element Length field. message elements is 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
skipping to change at page 46, line 38 skipping to change at page 48, line 38
Duplicate IPv6 Address 22 Duplicate IPv6 Address 22
Idle Timeout 23 Idle Timeout 23
Image Data 24 Image Data 24
Image Filename 25 Image Filename 25
Initiate Download 26 Initiate Download 26
Location Data 27 Location Data 27
MTU Discovery Padding 28 MTU Discovery Padding 28
Radio Administrative State 29 Radio Administrative State 29
Radio Operational State 30 Radio Operational State 30
Result Code 31 Result Code 31
Returned Message Element 46
Session ID 32 Session ID 32
Statistics Timer 33 Statistics Timer 33
Vendor Specific Payload 34 Vendor Specific Payload 34
WTP Board Data 35 WTP Board Data 35
WTP Descriptor 36 WTP Descriptor 36
WTP Fallback 37 WTP Fallback 37
WTP Frame Tunnel Mode 38 WTP Frame Tunnel Mode 38
WTP IPv4 IP Address 39 WTP IPv4 IP Address 39
WTP MAC Type 40 WTP MAC Type 40
WTP Name 41 WTP Name 41
WTP Operational Statistics 42 WTP Operational Statistics 42
WTP Radio Statistics 43 WTP Radio Statistics 43
WTP Reboot Statistics 44 WTP Reboot Statistics 44
WTP Static IP Address Information 45 WTP Static IP Address Information 45
4.4.1. AC Descriptor 4.5.1. AC Descriptor
The AC payload message element is used by the AC to communicate it's The AC payload message element is used by the AC to communicate it's
current state. The value contains the following fields. 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Security | R-MAC Field |Wireless Field | Reserved | | Security | R-MAC Field |Wireless Field | DTLS Policy |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Vendor Identifier | | Vendor Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=4 | Length | | Type=4 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value... | Value...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Vendor Identifier | | Vendor Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=5 | Length | | Type=5 | Length |
skipping to change at page 48, line 7 skipping to change at page 50, line 7
Max WTPs: The maximum number of WTPs supported by the AC Max WTPs: The maximum number of WTPs supported by the AC
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 4.1). in the CAPWAP transport Header (see Section 4.2).
Wireless Field: The AC supports the optional Wireless Specific Wireless Field: The AC supports the optional Wireless Specific
Information field in the CAPWAP Header (see Section 4.1). Information field in the CAPWAP Header (see Section 4.2).
Reserved: All implementations complying with this protocol MUST set DTLS Policy: The AC communicates its policy on the use of DTLS for
to zero any bits that are reserved in the version of the protocol the CAPWAP data channel. The AC MAY communicate more than one
supported by that implementation. Receivers MUST ignore all bits supported option, represented by the bit field below. The WTP
not defined for the version of the protocol they support. MUST abide by one of the options communicated by AC. The
following bit field values are supported:
1 - Clear Text Data Channel Supported
2 - DTLS Enabled Data Channel Supported
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" Network Management Private Enterprise Codes"
Type: Vendor specific encoding of AC information. The following Type: Vendor specific encoding of AC information. The following
values are supported. The Hardware and Software Version values values are supported. The Hardware and Software Version values
MUST be included. MUST be included.
4 - Hardware Version: The AC's hardware version number. 4 - Hardware Version: The AC's hardware version number.
5 - Software Version: The AC's Firmware version number. 5 - Software Version: The AC's Firmware version 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.
4.4.2. AC IPv4 List 4.5.2. 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 List Type: 2 for AC List
Length: 4 Length: 4
The AC IP Address: An array of 32-bit integers containing an AC's The AC IP Address: An array of 32-bit integers containing an AC's
IPv4 Address. IPv4 Address.
4.4.3. AC IPv6 List 4.5.3. 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 49, line 29 skipping to change at page 51, 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 32-bit integers containing an AC's The AC IP Address: An array of 32-bit integers containing an AC's
IPv6 Address. IPv6 Address.
4.4.4. AC Name 4.5.4. 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's identity. The value is a variable length byte string. The AC's identity. The value is a variable length byte string. 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
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Name ... | Name ...
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
skipping to change at page 49, line 40 skipping to change at page 52, line 4
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's identity. The value is a variable length byte string. The AC's identity. The value is a variable length byte string. 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
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| 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
4.4.5. AC Name with Index 4.5.5. 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 where this to configure preferred ACs. The number of instances where this
message element would be present is equal to the number of ACs message element would be present is equal to the number of ACs
configured on the WTP. 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...
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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 (e.g., 1=primary, Index: The index of the preferred server (e.g., 1=primary,
2=secondary). 2=secondary).
AC Name: A variable length UTF-8 encoded string containing the AC's AC Name: A variable length UTF-8 encoded string containing the AC's
name. name.
4.4.6. AC Timestamp 4.5.6. 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's clock. WTP's 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 50, line 42 skipping to change at page 53, line 4
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].
4.4.7. Add MAC ACL Entry 4.5.7. 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 any service to the MAC addresses provided in the no longer provides any 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 51, line 22 skipping to change at page 53, line 32
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 7 for Add MAC ACL Entry Type: 7 for Add MAC ACL Entry
Length: >= 7 Length: >= 7
Num of Entries: The number of MAC Addresses in the array. Num of Entries: The number of MAC Addresses in the array.
MAC Address: An array of MAC Addresses to add to the ACL. MAC Address: An array of MAC Addresses to add to the ACL.
4.4.8. Add Station 4.5.8. 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 particular station. The Add that it should forward traffic for a particular station. The Add
Station message element will be accompanied by technology specific Station message element will be accompanied by technology specific
binding information element which may include security parameters. binding information element 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 particular station. the particular station.
Once a station's policy has been pushed to the WTP through this Once a station's policy has been pushed to the WTP through this
message element, an AC may change any policies by simply sending a message element, an AC may change any policies by simply sending a
skipping to change at page 52, line 15 skipping to change at page 54, line 26
Radio ID: An 8-bit value representing the radio Radio ID: An 8-bit value representing the radio
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.
4.4.9. Add Static MAC ACL Entry 4.5.9. 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 52, line 39 skipping to change at page 55, line 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 9 for Add Static MAC ACL Entry Type: 9 for Add Static MAC ACL Entry
Length: >= 7 Length: >= 7
Num of Entries: The number of MAC Addresses in the array. Num of Entries: The number of MAC Addresses in the array.
MAC Address: An array of MAC Addresses to add to the permanent ACL. MAC Address: An array of MAC Addresses to add to the permanent ACL.
4.4.10. CAPWAP Control IPv4 Address 4.5.10. 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. In the event that multiple CAPWAP Control IPV4 Address connected. In the event that multiple CAPWAP Control IPV4 Address
message elements are returned, the WTP is expected to perform load message elements are returned, the WTP is expected to perform load
balancing across the multiple interfaces. balancing across 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 53, line 21 skipping to change at page 55, line 30
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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.
4.4.11. CAPWAP Control IPv6 Address 4.5.11. 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 53, line 42 skipping to change at page 56, line 4
| IP Address | | IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address | | IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address | | IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address | | IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| WTP Count | | WTP Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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.
4.4.12. CAPWAP Timers 4.5.12. 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 packets, Discovery: The number of seconds between CAPWAP Discovery packets,
when the WTP is in the discovery mode. when the WTP is in the discovery mode.
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 can be found messages. The default value for this message element can be found
in Section 4.5.4. in Section 4.6.6.
4.4.13. Data Transfer Data 4.5.13. 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 54, line 41 skipping to change at page 57, line 4
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 ....
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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.
4.4.14. Data Transfer Mode 4.5.14. 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 55, line 31 skipping to change at page 57, line 38
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
4.4.15. Decryption Error Report 4.5.15. 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 via the AC. encryption and decryption services are provided via 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 | Station MAC Address | | Radio ID |Num Of Entries | Station MAC Address |
skipping to change at page 55, line 45 skipping to change at page 58, line 4
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 via the AC. encryption and decryption services are provided via 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 | Station MAC Address | | Radio ID |Num Of Entries | Station MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Station MAC Address[] | | Station MAC Address[] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 15 for Decryption Error Report Type: 15 for Decryption Error Report
Length: >= 8 Length: >= 8
Radio ID: The Radio Identifier, which typically refers to an Radio ID: The Radio Identifier, which typically refers to an
interface index on the WTP interface index on the WTP
Num Of Entries: An 8-bit unsigned integer indicating the number of Num Of Entries: An 8-bit unsigned integer indicating the number of
station MAC addresses. station MAC addresses.
Station MAC Address: An array of station MAC addresses that have Station MAC Address: An array of station MAC addresses that have
caused decryption errors. caused decryption errors.
4.4.16. Decryption Error Report Period 4.5.16. 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. error report messages.
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 | Report Interval | | Radio ID | Report Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 16 for Decryption Error Report Period Type: 16 for Decryption Error Report Period
Length: 3 Length: 3
Radio ID: The Radio Identifier, typically refers to some interface Radio ID: The Radio Identifier, typically refers to some interface
index on the WTP index on the 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 4.6.6. in Section 4.7.7.
4.4.17. Delete MAC ACL Entry 4.5.17. 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| MAC Address[] | | Num of Entries| MAC Address[] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 57, line 4 skipping to change at page 59, line 5
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| MAC Address[] | | Num of Entries| MAC Address[] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC Address[] | | MAC Address[] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 17 for Delete MAC ACL Entry Type: 17 for Delete MAC ACL Entry
Length: >= 7 Length: >= 7
Num of Entries: The number of MAC Addresses in the array. Num of Entries: The number of MAC Addresses in the array.
MAC Address: An array of MAC Addresses to delete from the ACL. MAC Address: An array of MAC Addresses to delete from the ACL.
4.4.18. Delete Station 4.5.18. Delete Station
The Delete Station message element is used by the AC to inform an WTP The Delete Station message element is used by the AC to inform an 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 immediately upon receiving this The WTP must terminate service immediately upon receiving this
message element. 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, as a result of various reasons, including for administrative reasons, as a result of
the fact that the station has roamed to another WTP, etc. the fact that the station has roamed to another WTP, etc.
The Delete Station message element MAY be sent by the WTP, through
the WTP Event Request, to inform the AC that a particular station is
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
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 | MAC Address | | Radio ID | MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC Address | | MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 18 for Delete Station Type: 18 for Delete Station
Length: 7 Length: 7
Radio ID: An 8-bit value representing the radio Radio ID: An 8-bit value representing the radio
MAC Address: The station's MAC Address MAC Address: The station's MAC Address
4.4.19. Delete Static MAC ACL Entry 4.5.19. 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| MAC Address[] | | Num of Entries| MAC Address[] |
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Type: 19 for Delete Static MAC ACL Entry Type: 19 for Delete Static MAC ACL Entry
Length: >= 7 Length: >= 7
Num of Entries: The number of MAC Addresses in the array. Num of Entries: The number of MAC Addresses in the array.
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.
4.4.20. Discovery Type 4.5.20. 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 58, line 41 skipping to change at page 61, line 4
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 4 - AC Referral
4.4.21. Duplicate IPv4 Address 4.5.21. 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 it is currently using. address it is currently using.
The WTP shall transmit this message element after it has detected a
duplicate IP address. The WTP will consider the condition cleared
once it has successfully received a frame from the AC.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC Address | | MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC Address | | MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 21 for Duplicate IPv4 Address Type: 21 for Duplicate IPv4 Address
Length: 10 Length: 10
IP Address: The IP Address currently used by the WTP. IP Address: The IP Address currently used by the WTP.
MAC Address: The MAC Address of the offending device. MAC Address: The MAC Address of the offending device.
4.4.22. Duplicate IPv6 Address 4.5.22. 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 it an AC that it has detected another host using the same IP address it
is currently using. is currently using.
The WTP shall transmit this message element after it has detected a
duplicate IP address. The WTP will consider the condition cleared
once it has successfully received a frame from the AC.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address | | IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address | | IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address | | IP Address |
skipping to change at page 60, line 7 skipping to change at page 62, line 29
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 22 for Duplicate IPv6 Address Type: 22 for Duplicate IPv6 Address
Length: 22 Length: 22
IP Address: The IP Address currently used by the WTP. IP Address: The IP Address currently used by the WTP.
MAC Address: The MAC Address of the offending device. MAC Address: The MAC Address of the offending device.
4.4.23. Idle Timeout 4.5.23. 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 it with the idle timeout that it should enforce on its active provide it with the idle timeout that it should enforce on its active
station entries. The value applies for all radios on the WTP. station entries. The value applies for 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 can be found in default value for this message element can be found in
Section 4.6.3. Section 4.7.4.
4.4.24. Image Data 4.5.24. 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 | Checksum | Image Data | | Opcode | Checksum | Image Data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Image Data ... | | Image Data ... |
skipping to change at page 61, line 4 skipping to change at page 63, line 27
Type: 24 for Image Data Type: 24 for Image Data
Length: >= 4 (allows 0 length element if last data unit is 1024 Length: >= 4 (allows 0 length element if last data unit is 1024
bytes) bytes)
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:
3 - Image data is included 3 - Image data is included
5 - An error occurred. Transfer is aborted 5 - An error occurred. Transfer is aborted
Checksum: A 16-bit value containing a checksum of the image data Checksum: A 16-bit value containing a checksum of the image data
that follows that follows. The checksum field is the 16 bit one's complement
of the one's complement sum of all 16 bit words in the header.
For purposes of computing the checksum, the value of the checksum
field is zero.
Image Data: The Image Data field contains 1024 characters, unless Image Data: The Image Data field contains 1024 characters, unless
the payload being sent is the last one (end of file). If the last the payload being sent is the last one (end of file). If the last
block was 1024 in length, an Image Data with a zero length payload block was 1024 in length, an Image Data with a zero length payload
is sent. is sent.
4.4.25. Image Filename 4.5.25. Image Filename
The image filename message element is sent by the WTP to the AC and The image filename message element is sent by the WTP to the AC and
is used to initiate the firmware download process. This message is used to initiate the firmware download process. This message
element contains the image filename, which the AC subsequently element contains the image filename, which the AC subsequently
transfers to the WTP via the Image Data message element. The value transfers to the WTP via the Image Data message element. The value
is a variable length UTF-8 encoded string, which is NOT zero is a variable length UTF-8 encoded string, which is NOT zero
terminated. 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
skipping to change at page 61, line 36 skipping to change at page 64, line 18
| Filename ... | | Filename ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 25 for Image Filename Type: 25 for Image Filename
Length: >= 1 Length: >= 1
Filename: A variable length UTF-8 encoded string containing the Filename: A variable length UTF-8 encoded string containing the
filename to download. filename to download.
4.4.26. Initiate Download 4.5.26. 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 it should initiate a firmware upgrade. This is performed by WTP that it should initiate a firmware upgrade. This is performed by
having the WTP initiate its own Image Data Request, with the Image having the WTP initiate its own Image Data Request, with the Image
Download message element. This message element does not contain any Download message element. This message element does not contain any
data. data.
Type: 24 for Initiate Download Type: 24 for Initiate Download
Length: 0 Length: 0
4.4.27. Location Data 4.5.27. 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 for the WTP location to be determined administrator, and allows for the WTP location to be determined
through this field. The string is not zero terminated. through this field. The 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: 27 for Location Data Type: 27 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.
4.4.28. MTU Discovery Padding 4.5.28. 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...
+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-
Type: 28 for MTU Discovery Padding Type: 28 for MTU Discovery Padding
Length: variable Length: variable
Pad: A variable length pad. Pad: A variable length pad.
4.4.29. Radio Administrative State 4.5.29. 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 configuration of the Radio the state of a particular radio. The configuration of the Radio
Administrative State is sent by the AC to change the state of the Administrative State is sent by the AC to change the state of the
WTP, which saves the value to ensure its effect remains across WTP WTP, which saves the value to ensure its effect remains across WTP
resets. The WTP communicates this message element during the resets. The WTP communicates this message element during the
configuration phase to ensure that AC has the WTP radio's current configuration phase to ensure that AC has the WTP radio's current
administrative state settings. The value contains the following administrative state settings. The value contains the following
fields. fields.
skipping to change at page 63, line 25 skipping to change at page 66, line 7
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 itself. Therefore, if an AC wishes to change to identify the WTP itself. Therefore, if an AC wishes to change
the administrative state of a WTP, it would include 0xff in the the administrative state of a WTP, it would include 0xff in the
Radio ID field. 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 Section 4.6.1. The following values are listed in section Section 4.7.1. The following values are
supported: supported:
1 - Enabled 1 - Enabled
2 - Disabled 2 - Disabled
Cause: In the event of a radio being inoperable, the cause field Cause: In the event of a radio being inoperable, the cause field
would contain the reason the radio is out of service. The would contain the reason the radio is out of service. The
following values are supported: following values are supported:
0 - Normal 0 - Normal
1 - Radio Failure 1 - Radio Failure
2 - Software Failure 2 - Software Failure
3 - Radar Detection 3 - Radar Detection
4.4.30. Radio Operational State 4.5.30. 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 change in the operational state of a radio. For AC to communicate a change in the operational state of a radio. For
instance, if the WTP were to detect that a hardware failure existed instance, if the WTP were to detect that a hardware failure existed
with a radio, which caused the radio to be taken offline, the WTP with a radio, which caused the radio to be taken offline, the WTP
would indicate this event to the AC via the message element. The AC would indicate this event to the AC via the message element. The AC
MAY also send this message element to change the operational state of MAY also send this message element to change the operational state of
a specific radio. Note that the operational state setting is not a specific radio. Note that the operational state setting is not
saved on the WTP, and therefore does not remain across WTP resets. saved on the WTP, and therefore does not remain across WTP resets.
The value contains two fields, as shown. The value contains two fields, as shown.
skipping to change at page 64, line 38 skipping to change at page 67, line 21
following values are supported: following values are supported:
0 - Normal 0 - Normal
1 - Radio Failure 1 - Radio Failure
2 - Software Failure 2 - Software Failure
3 - Administratively Set 3 - Administratively Set
4.4.31. Result Code 4.5.31. 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 operation corresponding to the indicating the result of the request operation corresponding to the
sequence number in the message. sequence number 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Result Code | | Result Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 65, line 21 skipping to change at page 68, line 4
1 Failure (AC List message element MUST be present) 1 Failure (AC List message element MUST be present)
2 Success (NAT detected) 2 Success (NAT detected)
3 Failure (unspecified) 3 Failure (unspecified)
4 Failure (Join Failure, Resource Depletion) 4 Failure (Join Failure, Resource Depletion)
5 Failure (Join Failure, Unknown Source) 5 Failure (Join Failure, Unknown Source)
6 Failure (Join Failure, Incorrect Data) 6 Failure (Join Failure, Incorrect Data)
7 Failure (Join Failure, Session ID already in use) 7 Failure (Join Failure, Session ID already in use)
8 Failure (Join Failure, WTP Hardware not supported) 8 Failure (Join Failure, WTP Hardware not supported)
9 Failure (Unable to Reset) 9 Failure (Unable to Reset)
4.4.32. Session ID 10 Failure (Unable to Apply Requested Configuration - Service
Provided Anyhow)
11 Failure (Unable to Apply Requested Configuration - Service Not
Provided)
12 Image Data Error (Invalid Checksum)
13 Image Data Error (Invalid Data Length)
14 Image Data Error (Other Error)
4.5.32. Returned Message Element
The Returned Message Element is sent by the WTP within the Change
State Event Request in order to communicate to the AC which message
elements in the Configuration Status Response it was unable to apply
locally. The Returned Message Element contains a result code that is
used to indicate the reason why the configuration could not be
applied, and encapsulates the offending message element.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reason | Message Element...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Reason: The reason why the configuration in the offending message
element could not be applied by the WTP
1 - Unknown Message Element
2 - Unsupported Message Element
3 - Unknown Message Element Value
4 - Unsupported Message Element Value
Message Element: The Message Element field encapsulates the message
element sent by the AC in the Configuration Status Response
message that caused the error.
4.5.33. 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 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 4 5 6 7 8 9 0 1 2
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session ID | | Session ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 32 for Session ID Type: 32 for Session ID
Length: 4 Length: 16
Session ID: A 32-bit random session identifier Session ID: A 16 octet random session identifier
4.4.33. Statistics Timer 4.5.34. 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 which it expects to receive updated inform the WTP of the frequency which it expects to receive updated
statistics. 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: 33 for Statistics Timer Type: 33 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 can be found in section seconds. The default value for this timer can be found in section
Section 4.6.8. Section 4.6.14.
4.4.34. Vendor Specific Payload 4.5.35. Vendor Specific Payload
The Vendor Specific Payload is used to communicate vendor specific The Vendor Specific Payload is used to communicate vendor specific
information between the WTP and the AC. The value contains the information between the WTP and the AC. The value contains the
following format: 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: 34 for Vendor Specific Type: 34 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" [12] Network Management Private Enterprise Codes" [13]
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.
4.4.35. WTP Board Data 4.5.36. 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 67, line 41 skipping to change at page 71, line 25
1 - WTP Serial Number: The WTP Serial Number MUST be included in 1 - WTP Serial Number: The WTP Serial Number MUST be included in
the WTP Board Data message element. the WTP Board Data message element.
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.
4.4.36. WTP Descriptor 4.5.37. 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
it's current hardware/firmware configuration. The value contains the it's current hardware/firmware configuration. The value contains the
following fields. 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 68, line 24 skipping to change at page 72, line 24
| Value... | Value...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Vendor Identifier | | Vendor Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=1 | Length | | Type=1 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value... | Value...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Vendor Identifier | | Vendor Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=0 | Length | | Type=2 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value... | Value...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 36 for WTP Descriptor Type: 36 for WTP Descriptor
Length: >= 31 Length: >= 31
Max Radios: An 8-bit value representing the number of radios (where Max Radios: An 8-bit value representing the number of radios (where
each radio is identified via the Radio ID, or RID, field) each radio is identified via the Radio ID, or RID, field)
skipping to change at page 69, line 7 skipping to change at page 73, line 7
communicate it's capabilities to the AC. A WTP that does not have communicate it's capabilities to the AC. A WTP that does not have
any encryption capabilities sets this field to zero (0). Refer to any encryption capabilities sets this field to zero (0). Refer to
the specific wireless binding for further specification of the the specific wireless binding for further specification of the
Encryption Capabilities field. Encryption Capabilities field.
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" Network Management Private Enterprise Codes"
Type: The following values are supported. The Hardware Version, Type: The following values are supported. The Hardware Version,
Software Version, and Boot Version values MUST be included. Software Version, and Boot Version values MUST be included.
0 - WTP Model Number: The WTP Model Number MUST be included in 0 - Hardware Version: The WTP's hardware version number.
the WTP Board Data message element.
1 - WTP Serial Number: The WTP Serial Number MUST be included in
the WTP Board Data message element.
2 - Board ID: A hardware identifier, which MAY be included in
the WTP Board Data mesage element.
3 - Board Revision A revision number of the board, which MAY be
included in the WTP Board Data message element.
4 - Hardware Version: The WTP's hardware version number.
5 - Software Version: The WTP's Firmware version number. 1 - Software Version: The WTP's Firmware version number.
6 - Boot Version: The WTP's boot loader's version number. 2 - Boot Version: The WTP's boot loader's 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.
4.4.37. WTP Fallback 4.5.38. 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 70, line 5 skipping to change at page 73, line 41
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 it is not connected to it, it SHOULD primary AC is available, and it is not connected to it, it SHOULD
automatically disconnect from its current AC and reconnect to its automatically disconnect from its current AC and reconnect to its
primary. If disabled, the WTP will only reconnect to its primary primary. If disabled, the WTP will only reconnect to its primary
through manual intervention (e.g., through the Reset Request through manual intervention (e.g., through the Reset Request
command). The default value for this field can be found in command). The default value for this field can be found in
section Section 4.6.9. The following values are supported: section Section 4.7.9. The following values are supported:
1 - Enabled 1 - Enabled
2 - Disabled 2 - Disabled
4.4.38. WTP Frame Tunnel Mode 4.5.39. 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 |
skipping to change at page 70, line 39 skipping to change at page 74, line 27
modes for station data which are supported by the WTP. The modes for station data which 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 4.2). All user traffic native IEEE 802.3 frames (see Section 4.3). 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 4.2). example Section 4.3).
7 - All: The WTP is capable of supporting all frame tunnel 7 - All: The WTP is capable of supporting all frame tunnel
modes. modes.
4.4.39. WTP IPv4 IP Address 4.5.40. 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: 39 for WTP IPv4 IP Address Type: 39 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.
4.4.40. WTP MAC Type 4.5.41. 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 |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
skipping to change at page 72, line 5 skipping to change at page 75, line 39
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.
4.4.41. WTP Name 4.5.42. 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: 41 for WTP Name Type: 41 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.
4.4.42. WTP Operational Statistics 4.5.43. 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 73, line 5 skipping to change at page 76, line 38
Wireless Transmit Queue Level: The percentage of Wireless Transmit Wireless Transmit Queue Level: The percentage of Wireless Transmit
queue utilization, calaculated as the sum of utilized transmit queue utilization, calaculated 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 wireless terminals. between the WTP and wireless terminals.
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.
4.4.43. WTP Radio Statistics 4.5.44. 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 74, line 26 skipping to change at page 78, line 20
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.
4.4.44. WTP Reboot Statistics 4.5.45. 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 |
skipping to change at page 75, line 44 skipping to change at page 79, 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)
4.4.45. WTP Static IP Address Information 4.5.46. 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 76, line 37 skipping to change at page 80, line 37
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.
4.5. CAPWAP Protocol Timers 4.6. CAPWAP Protocol Timers
A WTP or AC that implements CAPWAP discovery MUST implement the A WTP or AC that implements CAPWAP discovery MUST implement the
following timers. following timers.
4.5.1. DiscoveryInterval 4.6.1. DataChannelKeepAlive
The minimum time, in seconds, between sending data channel keep-alive
packets to the AC with which the WTP has joined. The default value
is 30 seconds.
4.6.2. DataChannelDeadInterval
The minimum time, in seconds, a WTP MUST wait without having received
data channel keep-alive packets before the destination for the data
channel keep-alive packets may be considered dead. Must be no less
than 2*DataChannelKeepAlive seconds and no greater that 240 seconds.
Default: 5
4.6.3. 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, before initiating a DTLS handshake. Discovery Response, before initiating a DTLS handshake.
Default: 5 Default: 5
4.5.2. DTLSRehandshake 4.6.4. DTLSRehandshake
The minimum time, in seconds, a WTP MUST wait for DTLS rehandshake to The minimum time, in seconds, a WTP MUST wait for DTLS rehandshake to
complete. complete.
Default: 10 Default: 10
4.5.3. DTLSSessionDelete 4.6.5. 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
4.5.4. EchoInterval 4.6.6. EchoInterval
The minimum time, in seconds, between sending echo requests to the AC The minimum time, in seconds, between sending echo requests to the AC
with which the WTP has joined. with which the WTP has joined.
Default: 30 Default: 30
4.5.5. KeyLifetime 4.6.7. KeyLifetime
The maximum time, in seconds, which a CAPWAP DTLS session key is The maximum time, in seconds, which a CAPWAP DTLS session key is
valid. valid.
Default: 28800 Default: 28800
4.5.6. MaxDiscoveryInterval 4.6.8. MaxDiscoveryInterval
The maximum time allowed between sending discovery requests from the The maximum time allowed between sending discovery requests from the
interface, in seconds. Must be no less than 2 seconds and no greater interface, in seconds. Must be no less than 2 seconds and no greater
than 180 seconds. than 180 seconds.
Default: 20 seconds. Default: 20 seconds.
4.5.7. NeighborDeadInterval 4.6.9. MaxFailedDTLSSessionRetry
The maximum number of failed DTLS session establishment attempts
before the CAPWAP device enters a silent period.
Default: 3.
4.6.10. 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
Echo Responses to its Echo Requests, before the destination for the Echo Responses to its Echo Requests, before the destination for the
Echo Request may be considered dead. Must be no less than Echo Request may be considered dead. Must be no less than
2*EchoInterval seconds and no greater than 240 seconds. 2*EchoInterval seconds and no greater than 240 seconds.
Default: 60 Default: 60
4.5.8. ResponseTimeout 4.6.11. ResponseTimeout
The minimum time, in seconds, which the WTP or AC must respond to a The minimum time, in seconds, which the WTP or AC must respond to a
CAPWAP Request message. CAPWAP Request message.
Default: 1 Default: 1
4.5.9. RetransmitInterval 4.6.12. RetransmitInterval
The minimum time, in seconds, which a non-acknowledged CAPWAP packet The minimum time, in seconds, which a non-acknowledged CAPWAP packet
will be retransmitted. will be retransmitted.
Default: 3 Default: 3
4.5.10. SilentInterval 4.6.13. SilentInterval
The minimum time, in seconds, a WTP MUST wait after failing to For a WTP, this is the minimum time, in seconds, a WTP MUST wait
receive any responses to its discovery requests, before it MAY again before it MAY again send discovery requests or attempt to a establish
send discovery requests. DTLS session. For an AC, this is the minimum time, in seconds, which
the AC should ignore all CAPWAP and DTLS packets received from the
WTP that is in the sulking state.
Default: 30 Default: 30
4.5.11. WaitJoin 4.6.14. StatisticsTimer
The default Statistics Interval is 120 seconds.
4.6.15. 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. CAPWAP Protocol Variables 4.7. CAPWAP Protocol Variables
A WTP or AC that implements CAPWAP discovery MUST allow for the A WTP or AC that implements CAPWAP discovery MUST allow for the
following variables to be configured by system management; default following variables to be configured by system management; default
values are specified, making explicit configuration unnecessary in values are specified, making explicit configuration unnecessary in
many cases. If the default values are explicitly overriden by the many cases. If the default values are explicitly overriden by the
AC, the WTP MUST save the values sent by the AC. AC, the WTP MUST save the values sent by the AC.
4.6.1. AdminState 4.7.1. AdminState
The default Administrative State value is enabled (1). The default Administrative State value is enabled (1).
4.6.2. DiscoveryCount 4.7.2. DiscoveryCount
The number of discoveries transmitted by a WTP to a single AC. This The number of discoveries transmitted by a WTP to a single AC. This
is a monotonically increasing counter. is a monotonically increasing counter.
4.6.3. IdleTimeout 4.7.3. FailedDTLSSessionCount
The number of failed DTLS session establishment attempts.
4.7.4. IdleTimeout
The default Idle Timeout is 300 seconds. The default Idle Timeout is 300 seconds.
4.6.4. MaxDiscoveries 4.7.5. MaxDiscoveries
The maximum number of discovery requests that will be sent after a The maximum number of discovery requests that will be sent after a
WTP boots. WTP boots.
Default: 10 Default: 10
4.6.5. MaxRetransmit 4.7.6. 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
4.6.6. ReportInterval 4.7.7. ReportInterval
The default Report Interval is 120 seconds. The default Report Interval is 120 seconds..
4.6.7. RetransmitCount 4.7.8. 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.
4.6.8. StatisticsTimer 4.7.9. WTPFallBack
The default Statistics Interval is 120 seconds.
4.6.9. WTPFallBack
The default WTP Fallback value is enabled (1). The default WTP Fallback value is enabled (1).
4.7. WTP Saved Variables 4.8. WTP Saved Variables
In addition to the values defined in Section 4.6, the following In addition to the values defined in Section 4.7, 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.
4.7.1. AdminRebootCount 4.8.1. AdminRebootCount
The number of times the WTP has rebooted administratively, defined in The number of times the WTP has rebooted administratively, defined in
Section 4.4.44. Section 4.5.45.
4.7.2. FrameEncapType 4.8.2. 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 4.4.38. Encapsulation Type is defined in Section 4.5.39.
4.7.3. LastRebootReason 4.8.3. LastRebootReason
The reason why the WTP last rebooted, defined in Section 4.4.44. The reason why the WTP last rebooted, defined in Section 4.5.45.
4.7.4. MacType 4.8.4. MacType
For WTPs that support multiple MAC Types, it is usefule to save the For WTPs that support multiple MAC Types, it is usefule to save the
value configured by the AC. The MAC Type is defined in value configured by the AC. The MAC Type is defined in
Section 4.4.40. Section 4.5.41.
4.7.5. PreferredACs 4.8.5. PreferredACs
The preferred ACs, with the index, defined in Section 4.4.5. The preferred ACs, with the index, defined in Section 4.5.5.
4.7.6. RebootCount 4.8.6. RebootCount
The number of times the WTP has rebooted, defined in Section 4.4.44. The number of times the WTP has rebooted, defined in Section 4.5.45.
4.7.7. Static ACL Table 4.8.7. 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 4.4.9. Static MAC ACL Entry message element, see Section 4.5.9.
4.7.8. Static IP Address 4.8.8. Static IP Address
The static IP Address assigned to the WTP, as configured by the The static IP Address assigned to the WTP, as configured by the
message element, see Section 4.4.45. message element, see Section 4.5.46.
4.7.9. WTPLinkFailureCount 4.8.9. 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 4.4.44. Section 4.5.45.
4.7.10. WTPLocation 4.8.10. WTPLocation
The WTP Location, defined in Section 4.4.27. The WTP Location, defined in Section 4.5.27.
4.7.11. WTPName 4.8.11. WTPName
The WTP Name, defined in Section 4.4.41. The WTP Name, defined in Section 4.5.42.
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
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NeighborDeadInterval. They MUST be sent after waiting for a random NeighborDeadInterval. They MUST be sent after waiting for a random
delay less than MaxDiscoveryInterval. A WTP MAY send up to a maximum delay less than MaxDiscoveryInterval. A WTP MAY send up to a maximum
of MaxDiscoveries Discovery Request messages, waiting for a random of MaxDiscoveries Discovery Request messages, waiting for a random
delay less than MaxDiscoveryInterval between each successive message. delay less than MaxDiscoveryInterval between each successive message.
If a Discovery Response message is not received after sending the If a Discovery Response message is not received after sending the
maximum number of Discovery Request messages, the WTP enters the maximum number of Discovery Request messages, the WTP enters the
Sulking state and MUST wait for an interval equal to SilentInterval Sulking state and MUST wait for an interval equal to SilentInterval
before sending further Discovery Request messages. before sending further Discovery Request messages.
The Discovery Request message may be sent as a unicast, broadcast or
multicast message.
Upon receiving a Discovery Request message, the AC will respond with Upon receiving a Discovery Request message, the AC will respond with
a Discovery Response message sent to the address in the source a Discovery Response message sent to the address in the source
address of the received discovery request message. address of the received discovery request 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 4.4.20 o Discovery Type, see Section 4.5.20
o WTP Descriptor, see Section 4.4.36 o WTP Board Data, see Section 4.5.36
o WTP Frame Tunnel Mode, see Section 4.4.38 o WTP Descriptor, see Section 4.5.37
o WTP MAC Type, see Section 4.4.40 o WTP Frame Tunnel Mode, see Section 4.5.39
o WTP MAC Type, see Section 4.5.41
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.
The Discovery Response message is sent by an AC after receiving a The Discovery Response message is sent by an AC after receiving a
Discovery Request message from a WTP. Discovery Request message from a WTP. As with the Discovery Request,
the Session ID field in the CAPWAP header MUST be set to zero.
When a WTP receives a Discovery Response message, it MUST wait for an When a WTP receives a Discovery Response message, it MUST wait for an
interval not less than DiscoveryInterval for receipt of additional interval not less than DiscoveryInterval for receipt of additional
Discovery Response messages. After the DiscoveryInterval elapses, Discovery Response messages. After the DiscoveryInterval elapses,
the WTP enters the DTLS-Init state and selects one of the ACs that the WTP enters the DTLS-Init state and selects one of the ACs that
sent a Discovery Response message and send a DTLS Handshake to that sent a Discovery Response message and send a DTLS Handshake to that
AC. AC.
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 4.4.1 o AC Descriptor, see Section 4.5.1
o AC Name, see Section 4.4.4 o AC Name, see Section 4.5.4
o CAPWAP Control IPv4 Address, see Section 4.4.10 o CAPWAP Control IPv4 Address, see Section 4.5.10
o CAPWAP Control IPv6 Address, see Section 4.4.11 o CAPWAP Control IPv6 Address, see Section 4.5.11
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. As a a means to discover when its primary AC becomes available. As a
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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 Discovery Request message, the AC responds with a Upon receipt of a Discovery Request message, the AC responds with a
Primary Discovery Response message sent to the address in the source Primary Discovery Response message sent to the address in the source
address of the received Primary Discovery Request message. 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 4.4.20 o Discovery Type, see Section 4.5.20
o WTP Descriptor, see Section 4.4.36 o WTP Board Data, see Section 4.5.36
o WTP Frame Tunnel Mode, see Section 4.4.38 o WTP Descriptor, see Section 4.5.37
o WTP MAC Type, see Section 4.4.40 o WTP Frame Tunnel Mode, see Section 4.5.39
o WTP MAC Type, see Section 4.5.41
o WTP Radio Information Element(s)that the AC supports; These are
defined by the individual link layer CAPWAP Binding Protocols.
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.
The Primary Discovery Response message is sent by an AC after The Primary Discovery Response message is sent by an AC after
receiving a Primary Discovery Request message. receiving a Primary Discovery Request message.
When a WTP receives a Primary Discovery Response message, it may When a WTP receives a Primary Discovery Response message, it may
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 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 4.4.1 o AC Descriptor, see Section 4.5.1
o AC Name, see Section 4.4.4 o AC Name, see Section 4.5.4
o CAPWAP Control IPv4 Address, see Section 4.4.10 o CAPWAP Control IPv4 Address, see Section 4.5.10
o CAPWAP Control IPv6 Address, see Section 4.4.11 o CAPWAP Control IPv6 Address, see Section 4.5.11
o WTP Radio Information Element(s)that the AC supports; These are
defined by the individual link layer CAPWAP Binding Protocols.
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
The Join Request message is used by a WTP to inform an AC that it The Join Request message is used by a WTP to inform an AC that it
wishes to provide services through the AC. A Join Request message is wishes to provide services through the AC. A Join Request message is
sent by a WTP after (optionally) receiving one or more Discovery sent by a WTP after (optionally) receiving one or more Discovery
Responses, and completion of DTLS session establishment. When an AC Responses, and completion of DTLS session establishment. When an AC
receives a Join Request message it responds with a Join Response receives a Join Request message it responds with a Join Response
message. message.
Upon completion of the DTLS handshake (synonymous with DTLS "session Upon completion of the DTLS handshake, which the WTP is notified via
establishment"), the WTP sends the Join Request message to the AC. the DTLSEstablished notification, sends the Join Request message to
Upon receipt of the Join Request Message, the AC generates a Join the AC. When the AC is notified of the DTLS session establishment,
Response message and sends it to the WTP, indicating success or it does not clear the WaitDTLS timer until it has received the Join
failure. Request message, at which time it generates a Join Response message
and sends it to the WTP, indicating success or failure.
If the AC rejects the Join Request, it sends a Join Response message If the AC rejects the Join Request, it sends a Join Response message
with a failure indication then enters the CAPWAP reset state, with a failure indication and initiates an abort of the DTLS session
resulting in shutdown of the DTLS session. via the DTLSAbort command.
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 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 4.4.27 o Location Data, see Section 4.5.27
o Session ID, see Section 4.4.32 o WTP Board Data, see Section 4.5.36
o WTP Descriptor, see Section 4.4.36 o WTP Descriptor, see Section 4.5.37
o WTP IPv4 IP Address, see Section 4.4.39 o WTP IPv4 IP Address, see Section 4.5.40
o WTP Name, see Section 4.4.41 o WTP Name, see Section 4.5.42
o Session ID, see Section 4.5.33
The following message element MAY be included in the Join Request
message.
o WTP Reboot Statistics, see Section 4.5.45
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 it. it is capable and willing to provide service to it.
Upon receipt of the DTLSClientHello, the AC creates session state The WTP, receiving a Join Response message, checks for success or
containing the WTP address, port and session ID, sets the WaitJoin
timer for the session, sends the Join Response message to the WTP.
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
WaitJoin timer for the session and proceeds to the Configure state. WaitDTLS timer for the session and proceeds to the Configure state.
Otherwise, the WTP enters the CAPWAP reset state, resulting in
shutdown of the DTLS session.
If the WaitJoin 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 associated message, the WTP MUST terminate the handshake, deallocate associated
session state and transition to the Discover state. session 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. In this MUST be treated in the same manner as AC non-responsiveness. In this
way, the WaitJoin timer will eventually expire, in which case the WTP way, the WaitDTLS timer will eventually expire, in which case the WTP
may (if it is so configured) attempt to join with an alternative AC. may (if it is so configured) attempt to join with an alternative AC.
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 4.4.2 o AC IPv4 List, see Section 4.5.2
o AC IPv6 List, see Section 4.4.3 o AC IPv6 List, see Section 4.5.3
o Result Code, see Section 4.4.31 o Result Code, see Section 4.5.31
o Session ID, see Section 4.4.32 o WTP Radio Information Element(s)that the AC supports; These are
defined by the individual link layer CAPWAP Binding Protocols.
The following message element MUST be included in the Join Response The following message element MUST be included in the Join Response
message. message.
o AC Descriptor, see Section 4.4.1 o AC Descriptor, see Section 4.5.1
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 content of the packet and respond to the WTP with a Configuration the content of the packet and respond to the WTP with a Configuration
Status Response message. Status Response message.
The Configuration Status message includes multiple Radio The Configuration Status message includes multiple Radio
Administrative State message Elements. There is one such message Administrative State message Elements. There is one such message
element for the WTP, and one message element per radio in the WTP. element for the WTP, and one message element per radio in the WTP.
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 4.4.4 o AC Name, see Section 4.5.4
o AC Name with Index, see Section 4.4.5 o AC Name with Index, see Section 4.5.5
o Radio Administrative State, see Section 4.4.29 o Radio Administrative State, see Section 4.5.29
o Statistics Timer, see Section 4.4.33 o Statistics Timer, see Section 4.5.34
o WTP Board Data, see Section 4.4.35 o WTP Reboot Statistics, see Section 4.5.45
o WTP Reboot Statistics, see Section 4.4.44
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 4.4.45 o WTP Static IP Address Information, see Section 4.5.46
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.
Configuration Status Response messages are sent by an AC after Configuration Status Response messages are sent by an AC after
receiving a Configure Request message. receiving a Configure Request message.
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When a WTP receives a Configuration Status Response message it acts When a WTP receives a Configuration Status Response message it acts
upon the content of the message, as appropriate. If the upon the content of the message, as appropriate. If the
Configuration Status Response message includes a Radio Operational Configuration Status Response message includes a Radio Operational
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 Radio, the WTP will transmit a Change State Event to of one of the Radio, the WTP will transmit a Change State Event to
the AC, as an acknowledgement of the change in state. the AC, as an acknowledgement of the change in state.
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 4.4.2 o AC IPv4 List, see Section 4.5.2
o AC IPv6 List, see Section 4.4.3 o AC IPv6 List, see Section 4.5.3
o CAPWAP Timers, see Section 4.4.12 o CAPWAP Timers, see Section 4.5.12
o Radio Operational Event, see Section 4.4.30 o Radio Operational Event, see Section 4.5.30
o Decryption Error Report Period, see Section 4.4.16 o Decryption Error Report Period, see Section 4.5.16
o Idle Timeout, see Section 4.4.23 o Idle Timeout, see Section 4.5.23
o WTP Fallback, see Section 4.4.37 o WTP Fallback, see Section 4.5.38
8.4. Configuration Update Request The following message element MAY be included in the Configuration
Status Response message.
o WTP Static IP Address Information, see Section 4.5.46
8.4. Configuration Status Acknowledge
The Configuration Status Acknowledge message is sent by a WTP and
provides a mechanism for the WTP to acknowledge or report an error
condition to the AC for a requested configuration.
Configuration Status Acknowledge messages are sent by a WTP after
receiving a Configure Response message.
The Configuration Status Acknowledge message carries a status code
and may contain any specific binding message elements that could not
be set as requested by the AC. If the WTP successfully applies the
configuration, it shall set the return code value to "Success". If
the WTP is unable to apply any part of the configuration, it shall
set the return code value to "Unable to Apply Requested
Configuration" Refer to the appropriate binding for the definition of
this structure.
When a AC receives a Configuration Status Acknowledge message it acts
upon the content of the message, as appropriate. If the
Configuration Status Response message includes a Radio Operational
State message element that causes a change in the operational state
of one of the Radio, the WTP will transmit a Change State Event to
the AC, as an acknowledgement of the change in state.
The following message elements MUST be included in the Configuration
Status Acknowledge message.
o Result Code, see Section 4.5.31
8.5. 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 an AC receives a Configuration Update Request message it will When an AC receives a Configuration Update Request message it will
respond with a Configuration Update Response message, with the respond with a Configuration Update Response message, with the
appropriate Result Code. appropriate Result Code.
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 4.4.5 o AC Name with Index, see Section 4.5.5
o AC Timestamp, see Section 4.4.6 o AC Timestamp, see Section 4.5.6
o Add MAC ACL Entry, see Section 4.5.7
o Add MAC ACL Entry, see Section 4.4.7 o Add Static MAC ACL Entry, see Section 4.5.9
o Add Static MAC ACL Entry, see Section 4.4.9 o CAPWAP Timers, see Section 4.5.12
o CAPWAP Timers, see Section 4.4.12 o Decryption Error Report Period, see Section 4.5.16
o Decryption Error Report Period, see Section 4.4.16 o Delete MAC ACL Entry, see Section 4.5.17
o Delete MAC ACL Entry, see Section 4.4.17 o Delete Static MAC ACL Entry, see Section 4.5.19
o Delete Static MAC ACL Entry, see Section 4.4.19 o Idle Timeout, see Section 4.5.23
o Idle Timeout, see Section 4.4.23 o Location Data, see Section 4.5.27
o Location Data, see Section 4.4.27 o Radio Operational State, see Section 4.5.30
o Radio Operational State, see Section 4.4.30 o Statistics Timer, see Section 4.5.34
o Statistics Timer, see Section 4.4.33 o WTP Fallback, see Section 4.5.38
o WTP Fallback, see Section 4.4.37 o WTP Name, see Section 4.5.42
o WTP Name, see Section 4.4.41 o WTP Static IP Address Information, see Section 4.5.46
8.5. Configuration Update Response 8.6. 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 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 4.4.31 Result Code, see Section 4.5.31
8.6. Change State Event Request 8.7. Change State Event Request
The Change State Event Request message is used by the WTP to inform The Change State Event Request message is used by the WTP for two
the AC of a change in the one of the WTP radio's operational state. main purposes:
The Change State Event Request message MUST sent by the WTP when it o When sent by the WTP following the reception Configuration Status
receives a Configuration Response message that includes a Radio Response from the AC, the WTP uses the Change State Event to
Operational State message element. It is also sent when the WTP provide an update on the WTP radio's operational state as well as
detects an operational failure with a radio. The Change State Event to confirm that the configuration provided by the AC was
Request message may be sent in either the Configure or Run state (see successfully applied.
Section 2.3.
o When sent during the Run state, the WTP uses the Change State
Event to notify the AC of an unexpected change in the WTP's radio
operational state.
When an AC receives a Change State Event Request message it will When an AC receives a Change State Event Request message it will
respond with a Change State Event Response message and make any respond with a Change State Event Response message and make any
necessary modifications to internal WTP data structures. necessary modifications to internal WTP data structures. The AC MAY
decide not to provide service to the WTP if it receives an error,
based on local policy, which is done by transitioning to the CAPWAP
Reset state.
The Change State Event Request is sent by a WTP to acknowledge or
report an error condition to the AC for a requested configuration
through the Configuration Status Response. The Change State Event
Request includes the Result Code message element, which indicates
whether the configuration was successfully applied. If the WTP is
unable to apply a specfic configuration request, it indicates the
failure by including one or more Returned Message Element message
elements (see Section 4.5.32).
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 message element, see Section 4.4.30 o Radio Operational State, see Section 4.5.30
8.7. Change State Event Response o Result Code, see Section 4.5.31
One or more of the following message elements MAY be present in the
Change State Event Request message.
o Returned Message Element, see Section 4.5.32
8.8. 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 carries no message elements. The Change State Event Response message carries no message elements.
Its purpose is to acknowledge the receipt of the Change State Event Its purpose is to acknowledge the receipt of the Change State Event
Request message. Request message.
The WTP does not need to perform any special processing of the Change The WTP does not need to perform any special processing of the Change
State Event Response message. State Event Response message.
8.8. Clear Configuration Request 8.9. Clear Configuration Request
The Clear Configuration Request message is used to reset a WTP's The Clear Configuration Request message is used to reset a WTP's
configuration. configuration.
The Clear Configuration Request message is sent by an AC to request The Clear Configuration Request message is sent by an AC to request
that a WTP reset its configuration to the manufacturing default that a WTP reset its configuration to the manufacturing default
configuration. The Clear Config Request message is sent while in the configuration. The Clear Config Request message is sent while in the
Run CAPWAP state. Run CAPWAP state.
The Clear Configuration Request message carries no message elements. The Clear Configuration Request message carries no message elements.
When a WTP receives a Clear Configuration Request message it resets When a WTP receives a Clear Configuration Request message it resets
its configuration to the manufacturing default configuration. its configuration to the manufacturing default configuration.
8.9. Clear Configuration Response 8.10. Clear Configuration Response
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 back to the manufacturing default values. configuration parameters back to the manufacturing default values.
The Clear Configuration Request message carries the message elements. The Clear Configuration Request message carries the message elements.
o Result Code, see Section 4.4.31 o Result Code, see Section 4.5.31
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. Image Data Request 9.1. Image Data Request
The Image Data Request message is used to update firmware on the WTP. The Image Data Request message is used to update firmware on the WTP.
This message and its companion response message are used by the AC to This message and its companion response message are used by the AC to
ensure that the image being run on each WTP is appropriate. ensure that the image being run on each WTP is appropriate.
Image Data Request messages are exchanged between the WTP and the AC Image Data Request messages are exchanged between the WTP and the AC
to download a new firmware image to the WTP. When a WTP or AC to download a new firmware image to the WTP. When a WTP or AC
receives an Image Data Request message it will respond with an Image receives an Image Data Request message it will respond with an Image
Data Response message. The message elements contained within the Data Response message. The message elements contained within the
Image Data Request is required in order to determine the intent of Image Data Request message are required to determine the intent of
the request. Note that only one message element may be present in the request.
any given Image Data Request message.
The decision that new firmware is to downloaded to the WTP can occur The decision that new firmware is to be downloaded to the WTP can
in one of two methods: occur in one of two methods:
When the WTP joins the AC, and each exchange their software When the WTP joins the AC, and each exchange their software
revision, the WTP may opt to initiate a firmware download by revision, the WTP may opt to initiate a firmware download by
sending an Image Data Request, which contains an Image Filename sending an Image Data Request, which contains an Image Filename
message element. message element.
Once the WTP is in the CAPWAP state, it is possible for the AC to Once the WTP is in the Configure state, it is possible for the AC
cause the WTP to initiate a firmware download by initiating an to cause the WTP to initiate a firmware download by sending an
Image Data Request, with the Initiate Download message element. Image Data Request message, with the Initiate Download and and
The WTP would then transmit the Image Filename message element to Image Filename message elements. The WTP then transmits the Image
start the download process. Data Request message,which includes the Image Filename message
element to start the download process.
Regardless of how the download was initiated, once the AC receives an Regardless of how the download was initiated, once the AC receives an
Image Data Request with the Image Filename message element, it begins Image Data Request with the Image Filename message element, it begins
the transfer process by transmitting its own request with the Image the transfer process by transmitting its own request with the Image
Data message element. This continues until the whole firmware image Data message element. This continues until the firmware image has
has been transfered. been transfered.
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 4.4.24 o Image Data, see Section 4.5.24
o Image Filename, see Section 4.4.25 o Image Filename, see Section 4.5.25
o Initiate Download, see Section 4.4.26 o Initiate Download, see Section 4.5.26
9.2. Image Data Response 9.2. 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. receipt of the Image Data Request message. The Result Code is
included to indicate whether a previously sent Image Data Request
message was invalid.
The Image Data Response message carries no message elements. The following message elements MUST be included in the Image Data
Response message.
No action is necessary on receipt. o Result Code, see Section 4.5.31
Upon receiving an error, the WTP MAY decide to retransmit a previous
Image Data Reqest, or abandon the firmware download to the WTP by
transitioning to the Reset state machine.
9.3. Reset Request 9.3. 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 carries no message elements. The Reset Request carries no message elements.
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9.4. Reset Response 9.4. Reset Response
The Reset Response message acknowledges the Reset Request message. The Reset Response message acknowledges the Reset Request message.
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 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 Result Code, see Section 4.4.31 o Result Code, see Section 4.5.31
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 indicating failure may opt to no longer receives a Reset Response indicating failure may opt to no longer
provide service to the WTP in question. provide service to the WTP in question.
9.5. WTP Event Request 9.5. WTP Event Request
WTP Event Request message is used by a WTP to send information to its 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 sent AC. The WTP Event Request message may be sent periodically, or sent
in response to an asynchronous event on the WTP. For example, a WTP in response to an asynchronous event on the WTP. For example, a WTP
MAY collect statistics and use the WTP Event Request message to 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
to inform the AC that it is no longer providing service to the
station. This could be the result of an Idle Timeout (see
Section 4.5.23), due to to resource shortages, or some other reason.
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. specific wireless technology.
o Decryption Error Report, see Section 4.4.15 o Decryption Error Report, see Section 4.5.15
o Duplicate IPv4 Address, see Section 4.4.21 o Duplicate IPv4 Address, see Section 4.5.21
o Duplicate IPv6 Address, see Section 4.4.22 o Duplicate IPv6 Address, see Section 4.5.22
o WTP Operational Statistics, see Section 4.4.42 o WTP Operational Statistics, see Section 4.5.43
o WTP Radio Statistics, see Section 4.4.43 o WTP Radio Statistics, see Section 4.5.44
o WTP Reboot Statistics, see Section 4.4.44 o WTP Reboot Statistics, see Section 4.5.45
o Delete Station, see Section 4.5.18
9.6. WTP Event Response 9.6. 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 issent by an AC after receiving a WTP A WTP Event Response message issent by an AC after receiving a WTP
Event Request message. Event Request message.
The WTP Event Response message carries no message elements. The WTP Event Response message carries no message elements.
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debugger function in the WTP also uses the Data Transfer Request debugger function in the WTP also uses the Data Transfer Request
message to send console output to the AC for debugging purposes. message to send console output to the AC for debugging purposes.
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 ith a Data Transfer Response message. The AC MAY log the the WTP ith a Data Transfer Response message. The AC MAY log the
information received. information received.
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 4.4.13 o Data Transfer Data, see Section 4.5.13
o Data Transfer Mode, see Section 4.4.14 o Data Transfer Mode, see Section 4.5.14
9.8. Data Transfer Response 9.8. 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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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 section or document for the definitions of the appropriate binding section or document for the definitions of the
messages elements that may be used in this control message. messages elements that may be used in this control 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. Station Configuration Request message.
o Add Station, see Section 4.4.8 o Add Station, see Section 4.5.8
o Delete Station, see Section 4.4.18 o Delete Station, see Section 4.5.18
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. The previously received Station Configuration Request message. The
following message element MUST be present in the Station following message element MUST be present in the Station
Configuration Response message. Configuration Response message.
o Result Code, see Section 4.4.31 o Result Code, see Section 4.5.31
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 two specific situations in which a NAT system may be used There are two specific situations in which a NAT system may be used
in conjunction with a CAPWAP-enabled system. The first consists of a in conjunction with a CAPWAP-enabled system. The first consists of a
configuration where the WTP is behind a NAT system. Given that all configuration where the WTP is behind a NAT system. Given that all
communication is initiated by the WTP, and all communication is communication is initiated by the WTP, and all communication is
performed over IP using two UDP ports, the protocol easily traverses performed over IP using two UDP ports, the protocol easily traverses
NAT systems in this configuration. NAT systems in this configuration.
It is, however, possible for two or more WTPs to reside behind the
same NAT system. In this instance, the AC would receive multiple
connection requests from the same IP address, and could end up
thinking all of the connection requests come from the same WTP. It
is important that the AC not disconnect another WTP's session as a
result of this situation occuring. Therefore, the AC should consider
the WTP's identity, which is communicated within the DTLS exchange
used to secure the CAPWAP control channel. The CAPWAP header
includes a Session Identifier field, which is used to match the
control and data plane. This allows the AC to match the control and
data plane flows from multiple WTPs behind the same NAT system
(therefore all sharing the same IP address).
The second configuration is one where the AC sits behind a NAT. Two The second configuration is one where the AC sits behind a NAT. Two
issues exist in this situation. First, an AC communicates its issues exist in this situation. First, an AC communicates its
interfaces, and associated WTP load on these interfaces, through the interfaces, and associated WTP load on these interfaces, through the
WTP Manager Control IP Address. This message element is currently WTP Manager Control IP Address. This message element is currently
mandatory, and if NAT compliance became an issue, it would be mandatory, and if NAT compliance became an issue, it would be
possible to either: possible to either:
1. Make the WTP Manager Control IP Address optional, allowing the WTP 1. Make the WTP Manager Control IP Address optional, allowing the WTP
to simply use the known IP Address. However, note that this to simply use the known IP Address. However, note that this
approach would eliminate the ability to perform load balancing of approach would eliminate the ability to perform load balancing of
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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
As it is currently specified, the CAPWAP protocol sits between the As it is currently specified, the CAPWAP protocol sits between the
security mechanisms specified by the wireless link layer protocol security mechanisms specified by the wireless link layer protocol
(e.g.IEEE 802.11) and AAA. One goal of CAPWAP is to bootstrap trust (e.g.IEEE 802.11i) and AAA. One goal of CAPWAP is to bootstrap trust
between the STA and WTP using a series of preestablished trust between the STA and WTP using a series of preestablished trust
relationships: relationships:
STA WTP AC AAA STA WTP AC AAA
============================================== ==============================================
DTLS Cred AAA Cred DTLS Cred AAA Cred
<------------><-------------> <------------><------------->
EAP Credential EAP Credential
<------------------------------------------> <------------------------------------------>
wireless link layer wireless link layer
(e.g. IEEE 802.11 PTK) (e.g.802.11 PTK)
<--------------> or <--------------> or
<---------------------------> <--------------------------->
(derived) (derived)
Within CAPWAP, DTLS is used to secure the link between the WTP and Within CAPWAP, DTLS is used to secure the link between the WTP and
AC. In addition to securing control messages, it's also a link in AC. In addition to securing control messages, it's also a link in
this chain of trust for establishing link layer keys. Consequently, this chain of trust for establishing link layer keys. Consequently,
much rests on the security of DTLS. much rests on the security of DTLS.
In some CAPWAP deployment scenarios, there are two channels between In some CAPWAP deployment scenarios, there are two channels between
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time clock, they SHOULD verify the certificate validity dates. If no time clock, they SHOULD verify the certificate validity dates. If no
real-time clock is available, the device SHOULD make a best-effort real-time clock is available, the device SHOULD make a best-effort
attempt to validate the certificate validity dates through other attempt to validate the certificate validity dates through other
means. Failure to check a certificate's temporal validity can make a means. Failure to check a certificate's temporal validity can make a
device vulnerable to man-in-the-middle attacks launched using device vulnerable to man-in-the-middle attacks launched using
compromised, expired certificates, and therefore devices should make compromised, expired certificates, and therefore devices should make
every effort to perform this validation. every effort to perform this validation.
Another important part of certificate authentication is binding a Another important part of certificate authentication is binding a
certificate to a particular device. There are many ways to certificate to a particular device. There are many ways to
accomplish this. Specificaiton of the certificate common name (CN) accomplish this. Specification of the certificate common name (CN)
as the WTP or AC MAC address formatted as ASCII HEX, for example, 01: as the WTP or AC MAC address formatted as ASCII HEX, for example, 01:
23:45:67:89:ab is REQUIRED for use with the CAPWAP protocol. During 23:45:67:89:ab is REQUIRED for use with the CAPWAP protocol. During
authentication, devices SHOULD ensure that the MAC address matches authentication, devices SHOULD ensure that the MAC address matches
the MAC address specified in the CAPWAP header. If this mechanism is the MAC address specified in the CAPWAP header. If this mechanism is
used, the ACs SHOULD maintain list of all authorized WTP MAC used, the ACs SHOULD maintain list of all authorized WTP MAC
addresses and the WTP SHOULD save the AC credential or credential addresses and the WTP SHOULD save the AC credential or credential
identifier. identifier.
12.4. AAA Security 12.4. AAA Security
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secret authentication as it is often vulnerable to dictionary secret authentication as it is often vulnerable to dictionary
attacks, but rather SHOULD use stronger underlying security attacks, but rather SHOULD use stronger underlying security
mechanisms. mechanisms.
13. IANA Considerations 13. 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. for this purpose.
IANA needs to assign a DHCP code point, currently identified as TBD
in the section Section 3.2. DHCP options are defined in RFC 1533
[10], and are listed by IANA at
http://www.iana.org/assignments/bootp-dhcp-parameters.
14. References 14. References
14.1. Normative References 14.1. 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., Crocker, S., and J. Schiller, "Randomness
Recommendations for Security", RFC 1750, December 1994. Recommendations for Security", RFC 1750, December 1994.
skipping to change at page 105, line 34 skipping to change at page 112, line 34
[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] Manner, J. and M. Kojo, "Mobility Related Terminology",
RFC 3753, June 2004. RFC 3753, June 2004.
[9] Clancy, C., "Security Review of the Light Weight Access Point [9] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security", RFC 4347, April 2006.
[10] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
Extensions", RFC 1533, October 1993.
[11] Clancy, C., "Security Review of the Light Weight Access Point
Protocol", May 2005, Protocol", May 2005,
<http://www.cs.umd.edu/~clancy/docs/lwapp-review.pdf>. <http://www.cs.umd.edu/~clancy/docs/lwapp-review.pdf>.
[10] Rescorla et al, E., "Datagram Transport Layer Security",
June 2004.
14.2. Informational References 14.2. Informational References
[11] "draft-ietf-capwap-protocol-binding-specification-ieee802dot11- [12] "draft-ietf-capwap-protocol-binding-specification-ieee802dot11-
00". 00".
[12] Reynolds, J., "Assigned Numbers: RFC 1700 is Replaced by an On- [13] Reynolds, J., "Assigned Numbers: RFC 1700 is Replaced by an On-
line Database", RFC 3232, January 2002. line Database", RFC 3232, January 2002.
[13] Modadugu et al, N., "The Design and Implementation of Datagram [14] Modadugu et al, N., "The Design and Implementation of Datagram
TLS", Feb 2004. TLS", Feb 2004.
Editors' Addresses Authors' Addresses
Pat R. Calhoun Pat R. Calhoun
Cisco Systems, Inc. Cisco Systems, Inc.
170 West Tasman Drive 170 West Tasman Drive
San Jose, CA 95134 San Jose, CA 95134
Phone: +1 408-853-5269 Phone: +1 408-853-5269
Email: pcalhoun@cisco.com Email: pcalhoun@cisco.com
Michael P. Montemurro Michael P. Montemurro
skipping to change at page 107, line 7 skipping to change at page 115, line 7
Dorothy Stanley Dorothy Stanley
Aruba Networks Aruba Networks
1322 Crossman Ave 1322 Crossman Ave
Sunnyvale, CA 94089 Sunnyvale, CA 94089
Phone: +1 630-363-1389 Phone: +1 630-363-1389
Email: dstanley@arubanetworks.com Email: dstanley@arubanetworks.com
Full Copyright Statement Full Copyright Statement
Copyright (C) The Internet Society (2006). Copyright (C) The IETF Trust (2007).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property Intellectual Property
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information made any independent effort to identify any such rights. Information
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