Control And Provisioning of Wireless Access Points (CAPWAP) Protocol Specification
RFC 5415

Network Working Group                                    P. Calhoun, Ed.
Request for Comments: 5415                           Cisco Systems, Inc.
Category: Standards Track                             M. Montemurro, Ed.
                                                      Research In Motion
                                                         D. Stanley, Ed.
                                                          Aruba Networks
                                                              March 2009

      Control And Provisioning of Wireless Access Points (CAPWAP)
                         Protocol Specification

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

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Calhoun, et al.             Standards Track                     [Page 1]
RFC 5415             CAPWAP Protocol Specification            March 2009

Abstract

   This specification defines the Control And Provisioning of Wireless
   Access Points (CAPWAP) Protocol, meeting the objectives defined by
   the CAPWAP Working Group in RFC 4564.  The CAPWAP protocol is
   designed to be flexible, allowing it to be used for a variety of
   wireless technologies.  This document describes the base CAPWAP
   protocol, while separate binding extensions will enable its use with
   additional wireless technologies.

Table of Contents

   1. Introduction ....................................................7
      1.1. Goals ......................................................8
      1.2. Conventions Used in This Document ..........................9
      1.3. Contributing Authors .......................................9
      1.4. Terminology ...............................................10
   2. Protocol Overview ..............................................11
      2.1. Wireless Binding Definition ...............................12
      2.2. CAPWAP Session Establishment Overview .....................13
      2.3. CAPWAP State Machine Definition ...........................15
           2.3.1. CAPWAP Protocol State Transitions ..................17
           2.3.2. CAPWAP/DTLS Interface ..............................31
      2.4. Use of DTLS in the CAPWAP Protocol ........................33
           2.4.1. DTLS Handshake Processing ..........................33
           2.4.2. DTLS Session Establishment .........................35
           2.4.3. DTLS Error Handling ................................35
           2.4.4. DTLS Endpoint Authentication and Authorization .....36
   3. CAPWAP Transport ...............................................40
      3.1. UDP Transport .............................................40
      3.2. UDP-Lite Transport ........................................41
      3.3. AC Discovery ..............................................41
      3.4. Fragmentation/Reassembly ..................................42
      3.5. MTU Discovery .............................................43
   4. CAPWAP Packet Formats ..........................................43
      4.1. CAPWAP Preamble ...........................................46
      4.2. CAPWAP DTLS Header ........................................46
      4.3. CAPWAP Header .............................................47
      4.4. CAPWAP Data Messages ......................................50
           4.4.1. CAPWAP Data Channel Keep-Alive .....................51